Electronic Surveillance in a Digital Age

ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

July 1995

Recommended Citation:
U.S. Congress,
Office of Technology Assessment,
Electronic Surveillance in a Digital Age,
OTA-BP-ITC-149
(Washington, DC: U.S. Government Printing Office, July 1995).

Foreword

Lawlessness and terrorism present new challenges to our society as the 21st Century approaches. Electronic surveillance is an invaluable tool in America's arsenal to fight crime in this era of high-speed, global communications.

Digital communications technology has recently outpaced the ability of the law enforcement agencies to implement court authorized wiretaps easily and effectively. To address this problem, the 103d Congress enacted the Communications Assistance for Law Enforcement Act (P.L. 103-414). This Act invokes the assistance of the telecommunications industry to provide technological solutions for accessing call information and call content for law enforcement agencies when legally authorized to do so.

The law enforcement community and the telecommunications industry are currently working collaboratively on solutions to implement the requirement of the Act. On September 27, 1994, Congressman Michael G. Oxley, a member or OTA's Technology Assessment Board, requested that OTA consider the technical aspects of implementing the law that will affect the ultimate cost to the government, the industry, and the rate payers.

This background paper reviews the progress of the industry and the law enforcement agencies in implementing the Act since its approval in October 1994. OTA extends its thanks to the Alliance for Telecommunications Industry Solutions (ATIS) that sponsors the Electronic Communications Service Providers (ECSP) committee, which is the forum for the collaborative efforts of the industry and law enforcement in seeking solutions for complying with the requirements of the Act. Without the willful cooperation of the ECSP, OTA would likely not have been able to accurately compile the information contained in this background paper.

Special acknowledgment is also given to the law enforcement community for its assistance that was extended through the Telecommunications Industry Liaison Unit (TILU) of the Federal Bureau of Investigation.

ROGER C. HERDMAN Director

Contents July 1995

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ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

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CONTENTS

1 Summary and Discussion

Congressional Request and Scope of the Study

The Communications Assistance for Law Enforcement Act (P.L. 103-414)

Principal Features of the Act

Law Enforcement's Requirements for Electronic Surveillance

Findings and Observations

2 Technical Aspects of Electronic Surveillance

Technologies

Switch-Base Solutions

Wireless Technologies

APPENDICES

A Section-by-Section Summary of the Communications

Assistance for Law Enforcement Act Public Law 103-414

B Electronic Surveillance Requirements Keyed to P.L. 103-414

C Related OTA Reports for Further Reading

Glossary

Chapter 1: Summary and Discussion

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ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

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SUMMARY AND DISCUSSION

The law enforcement community considers electronic surveillance (see footnote 1) to be an invaluable tool for fighting crime. Officials cite many instances where criminal activities were either subverted, or if crimes were perpetrated, those responsible were apprehended as a result of court-approved electronic surveillance by law enforcement agencies.

The use of court-authorized electronic surveillance became increasingly more important as the telephone system became a part of everyday life. For many years the law enforcement community successfully matched its ability to perform electronic surveillance with the development of telephone Technologies. The telephone industry worked cooperatively with law enforcement agencies to ensure that access to specific communications was available when the courts authorized such access.

When the telephone system was largely a network that connected handsets like the plain old black rotary dial telephones, wiretapping was largely a simple procedure of physically connecting a listening or monitoring device to a circuit associated with a telephone number. It was simple and inexpensive. But times have changed. Technology has raced ahead, the structure of the industry has changed, the number of carriers and services has multiplied; dependence on communications for business and personal life has increased, computers and data are becoming more important than voice traffic for business, and the nation has become enthralled with mobile communication.

In 1984, AT&T was divested of its regional operating companies that made up the Bell System in an antitrust settlement. Before then the American telephone system operated on standards and procedures set by AT&T, with equipment that was either built by its manufacturing affiliate or approved for use by the company. The system worked uniformly and predictably throughout the United States.

Prior to divestiture, the telephone system was largely based on analog technology, with calls originated and terminated over copper wires or cables, which were directed to the receiver by electrical contact switches. Microwave, and later satellite, communications spanned distances that copper did not cover through the 1960s. Those days are gone.

Analog technology is being replaced by digital technology, optical fiber is rapidly replacing copper cable, and computers are replacing electrical switches for directing and processing calls.

Computers are increasingly used to communicate with other computers that transmit and receive digital data and messages. Facsimile, still an analog- based technology, has grown remarkably as a preferred means of communication. Wireless technologies, like cellular telephones, have loosed the caller from the restraints of the telephone line, and has allowed freedom to communicate from autos, trains, boats, airplanes, and on foot. In the future it is expected that personal communications systems will allow anyone, anywhere, to place phone calls via satellite linked to the ground communication system. These developments have been precipitated by letting the innovative zeal of private entrepreneurs seek their own visions of what the technology should be after the divestiture or AT&T and the deregulation of the telephone industry. Many of the new developments have been made possible through the application of digital technology.

Transition from an AT&T-regulated monopoly to the telecommunications system of the future--i.e., a digitally based National Information Infrastructure (NII)--has been a process of chaotic development. No longer do proprietary standards and operating protocols of a monopoly provider determine the architecture, functions, and procedures of the national telecommunications system. Neither is it a certainty that one telecommunication device, standard, or transmission protocol will work with another. Nor is there uniform delivery of compatible and interoperable services, e.g., Integrated Systems Digital Network (ISDN), to all quarters of the country. Each of the Regional Bell Operating Companies (RBOCs), the independent telephone companies, the interexchange (long-distance) carriers, and the private competitive-access providers each have their own business plans and schedules for deploying technologies. The United States has traded the comfort of uniformity and predictability in its communication system for creative innovation and vigorous competition. The technological payoff for divestiture and deregulation has been large, but progress has not been without a price to the law enforcement community.

Access to electronic communications (both wire other electronic communications) for law enforcement, i.e., court-approved wiretaps, pen registers, and traps and traces, are not simple or routine procedures--neither technically, nor legally. (See box 1-A.)

Recent and continuing advances in electronic communications technology and services challenge, and at times erode, the ability of law enforcement agencies to fully implement lawful orders to intercept communications. These advances also challenge the ability of telecommunications carriers to meet their assistance responsibilities. Thus, law enforcement agencies are finding it increasingly difficult to deal with intercepted digital communication, which might now be voice, data, images, or video, or a mixture of all of them.

Even the concept of the "telephone number," which at one time identified the target subject of the court-ordered wiretap and was tied to a physical location, may now only be a number that begins the communication, then loses its identity with an individual or location as the call may be routed to others by the caller. Subscribers at fixed locations can program the central office to forward their incoming calls to other numbers during certain times of the day or days of the week or to forward or block calls originating from specific telephone numbers. Cellular telephones and the next generation of mobile communication, Personal Communication Services (PCS), enable the caller to travel over great distances while maintaining communications that are handed off to other service providers. Modern communication systems are no longer wires connected to a switch, but are digital lines linked to routing tables and computer databases that set up calls with other computers almost instantaneously. It is an era of intelligent networks, switch systems that do not require physical connections, a digital environment that allows sophisticated encryption, and a choice of communication modes from voice through video. Persons might not communicate verbally, but may instead use computers as intermediaries. Communication need no longer be immediate, such as a conversation among individuals, but instead may be a computer message or a voice message addressed to a "mailbox" that may be stored, which can be accessed by another party at a future time.

Law enforcement surveillance has become more difficult and more expensive as a consequence of these new technological innovations. What was once a simple matter of initiating a court-approved wiretap by attaching wires to terminal posts now requires the expert assistance of the communication service provider. Even the once specific, but routine, requirements of the courts to authorize a wiretap are today more complex because of modern communication technology.

There has been a sea change in communication technology, and the law enforcement agencies find it difficult to maintain electronic surveillance as new services and features are added to the nation's communication networks. During the late 1980s and early 1990s, the Federal Bureau of Investigation (FBI) and other law enforcement agencies began to take steps to address the challenges posed by advanced telecommunications technologies and services. By 1992, it was evident that legislation would be necessary to ensure a level playing field and offer measures to address compliance, security, and cost recovery. During the 103d Congress, the Clinton Administration proposed legislation to clarify the technical assistance provisions of existing electronic surveillance statutes; and in October 1994, Congress passed and the President approved the Communications Assistance for Law Enforcement Act (P.L. 103-414).

The Act requires the telecommunication industry to assist the law enforcement agencies in matching intercept needs with the demands placed on them by modern communication technology. The Act does not change the authority of the courts to approve pen registers and traps and traces (see footnote 2) as well as wiretaps, or for law enforcement agencies to execute them under court order. (see footnote 3)

Recognizing that existing equipment, facilities, or services

may have to be retrofitted to meet the assistance capability

requirements, the law provides that the Attorney General may

agree to pay telecommunications carriers for all reasonable

costs directly associated with the modifications to those

deployed systems. Accordingly, the Act authorizes the

appropriation of $500 million over four fiscal years to

reimburse telecommunications service providers for the

direct costs of retrofitting those systems installed or

deployed as of January 1, 1995. Generally speaking, costs

for achieving compliance for equipment installed after

January 1, 1995, are to be borne by the telecommunications

carrier for compliance determined to be "reasonably

achievable." The Act also allows for cost recovery for

reasonable costs expended for making modifications to

equipment, facilities, or services pursuant to the

assistance requirements through adjustments by the Federal

Communications Commission (FCC) to charges, practices,

classifications, and regulations in response to a carrier's

petition.

The combined cost to the telecommunication industry and to

the law enforcement agencies is likely to be significant.

However, supporters of the bill during the congressional

debate over the Act in the 103d Congress cited the

offsetting costs to society caused by crimes that might

result in the absence of improving law enforcement's

capabilities to conduct electronic surveillance. Congress

considered the balance of costs and benefits and determined

that the benefits from crime prevention outweighed the costs

of compliance.

Law enforcement believes that these costs will not have a

significant impact on either the shareholders or the

customers of the telecommunications industry. They contend

that costs not compensated under the Act will be spread

among customers, and that the impact on the average

telephone bill will be insignificant. While this may or may

not be true, the exact financial impact on the government,

companies, and their customers will not be known until

planning and implementation process as set forth in the Act.

At the time of this report those costs are unknown. (see

footnote 4)

At a time when federal budgets are being trimmed, the cost

of electronic surveillance is likely to increase sharply.

Much of the cost of new technology installed after January

1, 1995, will be borne by the service providers and their

subscribers. But there also will be a substantial financial

burden placed on state, federal, and local law enforcement

agencies to conduct and maintain surveillance after the new

technology is in place. The Act does not address these

costs.

CONGRESSIONAL REQUEST AND SCOPE OF THE STUDY

On September 27, 1994, Congressman Michael G. Oxley, a

member of OTA's Technology Assessment Board, requested that

OTA consider the cost factors of implementing the

Communications Assistance for Law Enforcement Act (P.L. 103-

414). In his letter requesting the study, Mr. Oxley observed

that during the debate preceding enactment, the costs of the

legislation and who should bear those costs were highly

controversial issues.

Congress finally agreed to authorize $500 million over

fiscal years 1995-98 for retrofitting the service provider's

pre-1995 services, largely based on its already installed

switches (the Attorney General may cover costs for new

equipment based on technology that is not "reasonably

achievable" as determined by the FCC). The $500 million was

a compromise among widely ranging estimates from the

telecommunication industry and the law enforcement agencies.

Both the industry and law enforcement's estimates were based

on assumptions about costs for modifying existing equipment

and deploying the technology, but the estimates were

generally not based on formal engineering cost analysis. OTA

further found that, for practical purposes, it is not

possible to develop reliable cost figures without knowing

what specific capacities for electronic surveillance the law

enforcement agencies will place on the service providers to

meet their surveillance needs. (see footnote 5)

The Act provides a process to obtain this information

through the collaboration of the law enforcement agencies

and the industry, but in the meantime, the clock is running

on the compliance deadline, while the Attorney General's

capabilities and capacity notification to the industry that

will scope the requirements (and upon which costs to the

carriers will be determined) is not due until October 1995.

Priorities and capability statements that must be prepared

by the industry in response to the Attorney General's

notification will follow within 180 days. After this process

is completed, it will be possible to estimate the immediate

costs of complying with the Act.

This collaborative process involves two different types of

organizations with differing goals. Law enforcement agencies

would like to be able to execute authorized electronic

surveillance without either technological impediments or

delay. Telecommunications carriers, on the other hand, are

reluctant to plan for modifications of their equipment and

facilities without an expectation that they will be

compensated for their costs. Consequently, in order to

facilitate the collaborative process, both parties consider

the appropriations authorized by the Act to be an important

factor in its success.

This study considers the technical factors that will affect

the rate of compliance with the requirements of the Act by

the industry, and will provide insights into the technical

components that will determine cost. OTA did not, and could

not during the period of this study, develop an aggregate

cost estimate for implementation of the Act. Only after the

Attorney General provides the notification of law

enforcement's capacity needs to the service providers and

equipment manufacturers, and engineering cost analyses are

done, will reliable and meaningful cost estimates be

available. It is doubtful that such estimates will be

available before the second quarter of 1996, given the time

schedule under the act. However, the description of the

technology and modifications required by the act as

summarized in this background paper indicate the scope and

complexity, and hence the likely subjective magnitude of the

costs involved.

During the debate preceding enactment, considerable

attention was given to sensitive issues of privacy and

personal rights and protections. This report does not

address these issues. OTA's commission to undertake this

study considers only those technical factors that enter into

the cost and deployment of the technologies required of the

telecommunications industry by the Act and the operation of

the National Information Infrastructure (NII) of the future

as it may affect the surveillance missions of law

enforcement agencies.

THE COMMUNICATIONS ASSISTANCE FOR LAW ENFORCEMENT ACT (P.L.

103-414)

An affirmative obligation for telecommunication service

providers to assist the law enforcement community in

authorized electronic intercepts has existed since Congress

amended Title III of the 1968 Omnibus Crime and Safe Streets

Act in 1970. (see footnote 6) This amendment clarified an

ambiguity in the 1968 law about the specific responsibility

of telecommunications carriers for assisting law enforcement

agencies in authorized wiretaps. (see footnote 7) The

Supreme Court in United States v. New York Telephone, 434

U.S. 159, 177 (1977) found that 18 U.S.C. 2518(4) required

the federal courts to compel telecommunication providers to

provide "any assistance necessary to accomplish an

electronic interception." The question of whether a carrier

has any obligation to design its equipment to facilitate an

authorized electronic surveillance under 18 U.S.C 2518(4)

was never litigated.

It was not until the technology explosion in the

communication industry in the 1980s made it more difficult

for law enforcement agencies to conduct authorized wiretaps

that the issue of design requirements arose. The

Communications Assistance For Law Enforcement Act makes it

clear that the service providers must now consider equipment

and system design as well as the capability to provide the

call content and call identification information needed by

law enforcement agencies, and the capacity that the law

enforcement agencies need to simultaneously intercept a

specified number of wiretaps. The Act also establishes a

process for reimbursing the service providers for their

expenses in meeting law enforcement's needs. (See appendix

A, Section-by- Section Summary)

PRINCIPAL FEATURES OF THE ACT

Coverage and Exclusions

All "telecommunications carriers" that are considered common

carriers must comply with the requirements of the Act. (see

footnote 8) This includes local exchange carriers,

competitive access providers (CAPs), interexchange carriers,

cellular carriers, providers of personal communication

services (PCS), and other mobile radio services. Cable

companies and electric utilities companies would be covered

if they provide telecommunications services for hire to the

public.

Companies providing "information services" are excluded from

the Act's requirements. Such services include electronic

messaging services, e.g., electronic mail, electronic forms

transfer, electronic document interchange (EDI), information

and databanks available for downloading by a subscriber, and

Internet service providers.

Capabilities Required

A telecommunications carrier must have the capability to

selectively isolate and intercept real-time electronic

traffic and call identification information and deliver it

in the appropriate format to law enforcement personnel off

the carrier's premises. The service provider may not reveal

the physical location of an intercept subject, other than

that information available from a telephone directory

number, unless so authorized by court order. A carrier must

be able to notify a law enforcement agency, during or

immediately after the transfer of control of the

communication to another carrier. Carriers are not

responsible for decryption unless they have provided that

encryption service to the intercept target. (See figures 1-

1A, 1-1B.)

Capacity Requirements

By October 25, 1995, the Attorney General must notify the

carriers of the law enforcement agencies' specific capacity

needs, i.e., the number of simultaneous interceptions that

must be planned for within each service provider's system.

This is expected to vary among the service providers, with

higher capacities required in larger urban areas, such as

the New York Metropolitan area, Miami, Los Angeles, etc.,

while few or no requirements may be placed on those carriers

serving some rural areas. On the other hand, cellular and

other mobile communication carriers may be required to equip a large proportio

n of their switches with wiretap

capabilities so that taps on intercept parties may be linked

as they roam among service areas.

The Attorney General must provide the carriers with two

estimates of needed capacity:

a. an actual capacity that covers the period through

October 25, 1998, and

b. an estimate of maximum capacity that would be

required on October 25, 1998 and beyond.

The Attorney General is to periodically review law

enforcement's needs and notify the industry of any changes

in maximum capacity.

Within 180 days after the Attorney General publishes the

capacity notifications, service providers must provide

statements that identify those areas where the carrier does

not have the capacity to simultaneously accommodate the

types of surveillance required. (See figure 1-2.)

Time for Performance

Within three years after the Attorney General notifies the

carrier of the initial capacity needed by the law

enforcement agencies, a carrier must be able to provide the

number of simultaneous interceptions specified (this date

will likely be in late 1998). After that time, service

providers must be capable of increasing the number of

simultaneous interceptions up to the maximum number

determined by the Attorney General. A carrier may petition

the Federal Communication Commission (FCC) for an extension

of the compliance deadline if meeting the capability

requirements is not reasonably achievable by the 1998

deadline. If the FCC agrees that compliance is not

reasonably achievable within that time span, the FCC may

grant an extension of up to two years (circa 2000). (See

figure 1-3.)

Collaboration

Carriers, manufacturers, and vendors are encouraged to

collaborate among themselves and with the law enforcement

agencies in developing and modifying technology and

equipment to meet law enforcement's needs. The Attorney

General represents the federal and state law enforcement

agencies in the collaborative process. As the representative

of law enforcement, the Attorney General must consult with

industry associations, standards-setting organizations,

telecommunication users, and state regulatory commissions to

facilitate implementation of the Act. The Federal Bureau of

Investigation (FBI) has been given the authority for

implementing the Act.

Carriers and manufacturers are protected from the risk of

being judged in noncompliance of the capability requirements

if they adopt an accepted technical standard, or an agreed

upon industry-government technical solution. However, the

absence of such standards or technical solutions does not

relieve the industry of its obligations under the Act.

If voluntary standards or technical solutions are not

available, or if an adopted standard or solution is judged

by anyone to be deficient, the FCC may be petitioned (by any

person or entity) to establish the necessary technical

requirements or standards to allow compliance with the Act.

Cost Reimbursement

The Attorney General is authorized to pay the direct costs

for modification of equipment, facilities, or services

necessary to meet the requirements of the Act for equipment

deployed prior to January 1, 1995, and for costs of

modifications after that date if they are determined to be

not "reasonably achievable." Five hundred million dollars

($500 million) is authorized to be appropriated over four

fiscal years, 1995 through 1998. (see footnote 9)

If the Attorney General does not agree to reimburse a

carrier that requests compensation, the carrier is

considered to be in compliance with the Act until that

equipment is replaced or significantly upgraded, or

otherwise undergoes major modification.

For equipment deployed after January 1, 1995, a carrier must

assume the expense of complying with the Act unless to do so

is not reasonably achievable, i.e., that compliance would

impose "significant difficulty or expense" on the carrier or

users. (see footnote 10) The FCC would determine whether

compliance would be reasonably achievable or not.

If compliance is deemed by the FCC not to be reasonably

achievable, the Attorney General may agree to pay the

carrier for costs of developing the capability to comply

with the Act. If the Attorney General does not agree to pay

such costs, the carrier is considered to be in compliance

with the Act. (see footnote 11)

The Act (through an amendment to the Communications Act of

1934) allows for cost recovery for continued compliance with

the Act to be built into the rate structure for interstate

and foreign communications under the jurisdiction of the

FCC. (Sec. 229(e)) Tolls and rates for intrastate

communications are largely determined by the states, and the

Act does not directly address cost recovery through

intrastate rate adjustment. (see footnote 12)

Implementation of the Act

Since January 1992, when President Bush authorized the

Department of Justice to proceed with legislation that led

to the enactment of P.L. 103-414, law enforcement officials

have been working with the telecommunication industry to

solve the problems associated with electronic surveillance

in a digital, high- speed communication environment. (see

footnote 13) In July 1992, the FBI, as spokesman for all

federal, state, and local law enforcement agencies,

published a document entitled Law Enforcement Requirements

for the Surveillance of Electronic Communication. The

document outlined law enforcement's requirements for the

surveillance of electronic communications and still

continues to guide the framework for government/industry

collaboration, though updated several times since then.

(see footnote 14) (See appendix B.)

In general, the telecommunication industry has been

compliant with regard to law enforcement's concerns for

maintaining wiretap capabilities in the face of

technological development. The major initial sticking point

in complying with the need of the law enforcement community

concerned who would be financially liable for meeting law

enforcement's needs. The companies would not unilaterally

invest money or technical resources to seek solutions to the

problems in the absence of a legal mandate that would ensure

that competing companies would be held to the same

requirements. Many, but not all, of the industries' concern

about reimbursement and fairness were dealt with in the

legislation. Recently, however, the industry has been more

concerned with how law enforcement's capacity requirements

will impact costs, and hence their future financial

liability.

The 1994 Act authorizes the appropriation of money for cost

reimbursement to meet law enforcement's requirements, and

contains a fail-safe provision that relieves a carrier of

its obligations under the Act if money is not provided to

offset the cost of compliance. Furthermore, a "safe harbor"

provision holds a carrier blameless if it deploys a

technical solution to meet law enforcement's requirements

that has been approved by a government-industry group, an

industry trade group, or a standard setting authority

capable of meeting law enforcement's capability requirements

under Section 103 of the Act.

The Attorney General has delegated much of the

responsibility for implementing the Act to the FBI. To

facilitate implementation, the Director of the FBI has

created the Telecommunication Industry Liaison Unit (TILU)

made up of 70 to 80 persons and specialists to coordinate

the efforts of the federal, state, and local law enforcement

agencies in collaborating with the industry. TILU is

intended to be a one-stop point of contact for all matters

dealing with compliance with the Act. Technical matters,

cost reimbursement, compliance with capabilities and

capacity, liaison with service providers and switch

manufacturers/vendors, etc., are to be coordinated through

this unit.

Even before the Act was passed, the law enforcement agencies

and the industry had begun a collaborative effort to

confront the problems of electronic surveillance. Building

on earlier consultation with the industry through an

informal industry technical working group that was convened

more than two years before passage of the Act, a more formal

arrangement was struck, which currently serves as the

primary focus of government/industry collaboration.

In March 1993, the Electronic Communications Service

Provider (ECSP) Committee was formed under the aegis of the

Alliance for Telecommunications Industry Solutions (ATIS),

an industry group aimed at resolving issues involving

telecommunications standards and the development of

operational guidelines. (see footnote 15) The ECSP committee

is co-chaired by an industry official and a representative

of the Attorney General who represents the collective views

of federal, state, and local law enforcement agencies.

ECSP is an open forum with over 200 individual participants

(however, only 40 to 60 persons have consistently

participated in the action teams), consisting of

representatives of local exchange carriers, interexchange

carriers, trade associations, industry consultants,

equipment manufacturers, and law enforcement officials,

among others. (see footnote 16) Each participant must sign

a nondisclosure agreement that is intended to both guard

information that might be useful to the criminal element and

to reduce the risk of divulging proprietary information,

while ensuring a free and open forum for discussing mutual

problems.

ECSP has created six action teams, each co-chaired by a

representative of the industry and a representative of the

law enforcement agencies:

o Advanced Intelligent Networks (AIN): Addresses solutions

to problems related to the next-generation telephone network

now in the initial stages of deployment. AIN involves the

deployment of software-controlled devices, including

signaling systems, switches, computer processors, and

databases. These functional units enable subscribers to

independently configure services to meet their needs, and in

doing so, create another layer of complexity for

wiretapping.

o Personal Communication Services (PCS): Considers

solutions to problems arising from development of the next

generation of wireless communication with the possible

future capability of spanning the world.

o Prioritization and Technology Review: Responsible for

establishing the priorities in attacking the problems

associated with the various communication technologies. The

action team is also charged with identifying future emerging

communication technologies and features that must be dealt

with in the future.

o Switch-Based Solutions: Develops recommendations to meet

the functional requirements for the central switch office-

based solutions to meet law enforcement's requirements,

including operational security.

o Interfaces: Assesses the requirements for physical,

messaging, operational, and procedural interfaces to meet

the needs of the law enforcement agencies.

o Cellular: Considers cellular technologies in the context

of law enforcement's intercept requirements.

The objective of the action teams is to explore the

implications of meeting law enforcement's electronic

surveillance requirements on the telecommunications

networks. To assist them in their objectives, they are

preparing a series of consensus documents to serve as

references for industry standards-setting bodies, service

providers, equipment manufacturers, and law enforcement

agencies. These documents, which are to be produced by each

action team, will generally include:

o Requirements and Capabilities Document,

o Interpretation of Requirements Document,

o Features and Description Document, and

o User Performance Document.

Industry standards groups will use these documents to

develop standards specifications that will guide

manufacturers in the development and production of switches

and other devices needed to meet the requirements of the law

enforcement agencies.

LAW ENFORCEMENT'S REQUIREMENTS FOR ELECTRONIC SURVEILLANCE

(see footnote 17)

The requirements of the law enforcement agencies apply to

all forms of electronic communications service providers.

The requirements are, however, generally couched in terms

that apply primarily to telephone communication.

Nonetheless, the same requirements apply to any industry

sector that provides common carriage of communications for

sale, including the cable television industry, public

utilities, and other forms of electronic communication,

except information service providers, which are expressly

exempted under the act.

These requirements, though stated in legal or descriptive

terms based on Section 103 of the Act, when translated by

engineers and service personnel into technical requirements,

impose stringent and substantial challenges to equipment

manufacturers and the service providers for meeting law

enforcement's needs.

Communications Access

Each service provider is required to have procedures capable

of activating and deactivating wiretaps within 24 hours

after receiving a lawful intercept request. Law enforcement

agencies may also require expeditious access to technical

resources or assistance in activating the intercept or to

obtain needed service information. In "emergency

situations," (e.g., in cases where rapid response is

required to eliminate threats to life, property, or national

security) law enforcement agencies require access to the

intercept subject's communication, and technical assistance

within a few hours.

Law enforcement agencies require access to all electronic

communications transmitted and received by an intercept

subject. Access must be provided from anywhere within the

service area of a service provider. Access to all call setup

information necessary to identify the calling and called

numbers, e.g., originating line number identification, and

terminating line number identification for all completed and

attempted calls, as well as access to the call content is

required. Under this requirement, the carrier remains in

custody of the call service, with the carrier's security

personnel activating or deactivating an intercept only when

presented with legal authority by a law enforcement agency.

Law enforcement agencies require that the service providers

have a 24-hour-per-day capability of accessing and

monitoring simultaneous calls originated or received by an

intercept subject at the moment the call is taking place.

Law enforcement agencies require carriers to provide for

implementing multiple simultaneous intercepts within a

service provider's system, central office or area. (see

footnote 18) This requirement includes the ability for

different law enforcement agencies to simultaneously monitor

the same intercept subject while maintaining confidentiality

among the agencies. Each carrier is required to support all

requested authorized intercepts within its service area. To

meet these requirements, service providers are required to

have reserve intercept capacity available to meet unexpected

demands, which are to be set forth by the Attorney General

on or before October 25, 1995. Law enforcement agencies need

to be able to access and monitor simultaneous calls placed

or received by an intercept subject without the intercept

being detected.

The service provider is only responsible for access as long

as the call is under its control or maintains access to the

call. If the original service provider does not maintain

access to the ongoing call, it is that service provider's

responsibility to provide any available information to law

enforcement that identifies the visited service area and/or

carrier. Once handed off to a second service provider, it is

the second provider's responsibility to provide the access

to law enforcement. The originating carrier, however, must

notify the law enforcement agency to which carrier the call

has been handed off.

Access is specifically required for call identifying

information.

Call identifying information includes, for example:

o information concerning an intercept targets connection or

transmission path to the network, (see footnote 19)

o information concerning a calling party's connection or

transmission path to the network when in contact with the

intercept subject,

o dialing and signaling information generated by the

intercept subject,

o directory numbers used in transferring or forwarding

calls, and

o notification that a call or call attempt has occurred.

The nature and type of call setup information will vary

depending on what type of communication service the calling

or terminating party is using, i.e., information available

from a call originated from a cellular phone will be

different than if the call originated through a wired

system. (See table 1-1.)

Dialing and Signaling Information

Law enforcement requires access to all dialing and signaling

information for all calls originated by the intercept

target, e.g., all digits dialed by the intercept subject and

any information used to establish or direct call flow. In

addition, after the call is completed (cut-through), law

enforcement requires dialing information generated by the

subject, e.g., touch-tone digits dialed to activate or code

a device at the point of call termination.

Examples of dialing and signaling information include:

o All digits dialed by the subject and any signaling

information used to establish or direct call flow, e.g.,

activating service features like call forwarding or three-

way calling.

o Subsequent dialing information generated by the subject

after cut-through (connection), e.g., dialed digits, voice

dialing, etc.

o The terminating or destination number derived by the

originating switch based on its interpretation of the

subject's dialed digits or other call direction commands.

Redirection Numbers

Access to call setup information includes redirection

numbers when calls are forwarded or transferred using custom

calling features, for example when multiple forwards or

transfers are involved in a call attempt. A call initiated

by a calling party to the intercept subject may be forwarded

or transferred several times before reaching the intercept

target. In those cases, law enforcement requires the number

of the party that originated the call, and any intermediate

numbers used to redirect the call. (see footnote 20) Access

is required to forwarded-to numbers if control of the call

remains with the service provider executing a lawful

wiretap.

Call Attempt Alerts

Notification of all call attempts placed by or to the

intercept target are required. Currently, in the case of

wireline communications intercepted in a local exchange

carrier's (LEC) service area, law enforcement agencies

generate a time stamp after automatically detecting signals

for ringing, or when a receiver is taken off or placed back

on its hook. New technologies will make the simple detection

methods more difficult as out-of-band (i.e., off-line)

signaling using computer-controlled signal transfer points

replaces conventional in-band (on-line) signaling systems

commonly used by many local exchange carriers today.

Therefore, law enforcement agencies will require some form

of notification from the carrier so that monitoring

equipment can be activated.

Call Content

Law enforcement agencies must have access to the contents

(see footnote 21) of calls placed or received by intercept

subjects. In some modes of transmission, the electronic

communication may be carried on two different channels

(duplex), with one party on one channel, and the other on a

second channel. Nonetheless, the carriers must provide

uninterrupted access to both channels simultaneously.

There are three possible combinations for placing and

receiving calls:

o wireline-to-wireline, including Plain Old Telephone

Service (POTS), coin operated service, and Integrated

Service Digital Network (ISDN);

o wireline-to-mobile or mobile-to-wireline, where one party

uses a cellular, PCS service or other wireless service, and

the second party uses a wireline service; and

o mobile-to-mobile services, where both parties use

cellular, PCS service or other wireless service (See figure

1-4.)

Custom calling features allow subscribers to forward or

redirect their calls, or set up conference calls involving

more than two parties. In these cases, a service provider is

required to provide access to the call so long as it

maintains access to the communications. If a call from an

intercept target is redirected so that the authorized

service provider loses access to the call, the provider must

notify the law enforcement agency of the identity of the

service provider who then has custody of the intercept call.

If the new service provider's identity is not known, the

carrier must provide any supplemental information that would

assist the law enforcement agency in determining the new

service provider's identity.

Mobile Communications

Requirements for accessing call setup information and call

content apply to both wireline and wireless mobile

communications. A mobile customer can move freely about a

home service area and beyond into the service area of

another mobile carrier. A service provider's network may

cover a local area, a region, a state, or portions of a

multistate area. When a single service provider covers a

large geographic area, that carrier is required to provide

access to an intercept subject's communication wherever it

takes place within the provider's extended service area

consistent with the court order authorizing the intercept.

Law enforcement agencies require access to an intercept

subject's communications throughout the area served by his

or her home service provider. When an intercept subject

travels into another service provider's area while

communicating, law enforcement agencies require access to

the ongoing call so long as the home service provider

maintains access to the call in progress. If access to the

call is not maintained by the home service provider, law

enforcement agencies require that the identity of the

service provider to which the call was handed off be made

available, or that information be provided that will enable

the new service provider to be identified. (See figure 1-5.)

The discussion above focused on the case where a mobile

intercept subject originated a call in his or her home

service provider area and traveled to an adjacent service

provider's area in the course of a call, and the call is

handed off to another service provider.

Subscribers who "roam" beyond their home service provider's

area and attempt to establish communication from another

service provider's area are registered as visitors in the

new service. In those instances, information about the

caller's unique Electronic Serial Number (ESN) and Mobile

Identification Number (MIN) and other authentication,

validation, and routing information are automatically

exchanged between the location registers (computer

databanks) of the two cellular service providers. (See

figure 1-6.)

Law enforcement agencies require access to information

regarding the identity of service providers that request

visitor's registration authorization from an intercept

subject's home service provider. The home service provider

must provide the law enforcement agencies with the visited

service provider's identity, and other data, such as service

site information of the carrier that is controlling the

intercept subject's communication.

Delivery of Information to Law Enforcement

Law enforcement agencies require that call content and call

setup information that is intercepted in response to an

authorized wiretap be transmitted to a designated law

enforcement monitoring facility. However, access to the

intercept will be controlled by the service provider and not

the law enforcement agency. Transmission of intercepted

communications must satisfy the following guidelines:

o Where call setup information and call content are

separated during interception, the service provider must

take steps to ensure accurate association of call setup

information with call content.

o Transmission of the intercepted communication to the

monitoring site must be made without altering the call

content or meaning.

o Law enforcement agencies require that the transmission

facilities and formats of the information transmitted the

monitoring stations be in a standard form.

o If the service provider controls and/or provides coding,

compression, encryption, or other security features for the

intercepted communications, the service provider must

decode, decompress, or decrypt intercepted messages before

transmission or provide the capabilities to the law

enforcement agency to reprocess the information.

o Law enforcement agencies require that the service

provider use a minimum number of transmission facilities to

deliver the intercepted communications to the monitoring

facility. Currently, most cellular service areas with

multiple Mobile Switching Centers (MSC) require a connection

from each MSC to the monitoring location for each

intercepted call.

Verification Information

Law enforcement agencies require that the carrier provide

information to verify or authenticate the linkage between

the intercepted communications and the intercept subject in

order to establish the wiretap as evidence in court,

however, it is law enforcement's responsibility to

authenticate the linkage. Prior to implementation of the

intercept, the service provider is obligated to provide the

law enforcement agency with information on the services and

features subscribed to by the intercept subject (service

profile).

Courts require law enforcement agencies to verify that the

communication that was monitored was that of the intercept

subject authorized in the lawful authorization of the

wiretap. This is done with a network identifier (directory

number), terminal identifier, personal identification

number, and billing and caller identification-related

information.

Service profile information, i.e., the service subscribed to

by an intercept subject, must be made available to a law

enforcement agency in response to a lawful inquiry before

and during an intercept. Service providers are obligated to

notify the law enforcement agency of changes in the

intercept subject's service profile during the progress of

an interception, even if the change is initiated directly by

the intercept subject without the involvement of the service

provider, e.g., call forwarding.

Reliability of Service

Reliability of service for intercepted communications

delivered to a law enforcement agency must be of equal

reliability as that of the intercept subject's service.

Service providers must also have the ability to detect and

solve problems with the interception of call setup

information or content information, as well as the

transmission of the intercepted information to the law

enforcement monitoring facility.

Quality of Service

The quality of the service supporting the intercept must be

at least equal to the quality of the service provided to the

intercept subject, measured by any objective factor, e.g.,

signal-to-noise ratio, bit error rate, or other parameters

that measure transmission quality.

Transparency of Interceptions

Intercepts must be undetectable by the intercept subject or

other callers, and known only to the monitoring law

enforcement agency and authorized personnel of the service

provider responsible for setting up the intercept. In some

cases, intercept subjects may use sophisticated equipment to

detect intercepts; nonetheless, service providers are

obligated only to provide transparency within the limits of

their equipment based on industry standards for transmission

characteristics. Benchmarks for meeting the transparency

requirement include:

o The subject should not be able to discern that an

intercept is in progress.

o If the intercept begins during a call in progress, the

intercept should not disrupt or interrupt the ongoing call.

o If in the process of interception, changes in services or

features occur, these changes should not be apparent to the

intercept subject or other parties

o Any line noise introduced by the intercept should not be

perceptible to the intercept subject or other parties.

Network and Intercept Security

Service providers are also required to adopt operating

procedures that safeguard against unauthorized or improper

intercept and to prevent compromise of transparency. Such

procedures include:

o internal restrictions on information about intercepts,

o security mechanisms for activating and deactivating

intercepts,

o physical security to limit access to systems supporting

intercepts,

o procedures to prevent disclosure of service changes

caused by implementation of intercepts, and

o restrictions on knowledge of the existence of intercepts

among service provider's employees.

Network security and integrity is addressed in Section 105

of the Act. (see footnote 22) The Act directs that only an

employee of a service provider can activate an intercept

after the receipt of a lawful authorization from a law

enforcement agency, according to procedures prescribed by

the Federal Communication Commission (FCC). (Sec. 229(b))

However, other security matters not addressed by the Act

figure prominently in maintaining network security

protecting the integrity of electronic surveillance.

Computer systems, in general, are susceptible to breaches of

security under the most strict controls. This is evident

from the violation of even relatively secure computer

systems and networks within the Department of Defense. The

modern telephone network is little more than an extension of

a series of interconnected wide-area computer networks

linked by transmission facilities. As such, telephone

systems suffer the same vulnerabilities as all networked

computer systems. (see footnote 23) Whether or not the

network may become more vulnerable as a consequence of

meeting law enforcement's intercept requirements under the

Act is uncertain. There is no empirical evidence that

suggests that it will at this time.

The complexity of sophisticated computer systems is their

source of vulnerability. Millions of lines of computer code

are needed to operate a large networked computer system. The

magnitude of the operating system creates hundreds of

potential opportunities or windows for penetrating the

system. On the other hand, a proficient person intent on

hacking into the system need only find one of these windows

to achieve his or her objective.

Maintaining a secure operational environment in the

administration of electronic intercepts is a major concern

in wiretap procedures. Security problems exist whether the

intercept involves switched landlines, mobile cellular

operations, or personal communication services. Security

protocols are needed to prevent unauthorized personnel from:

Initiating or terminating surveillance; obtaining

information about a surveillance in progress; monitoring the

results of a surveillance; determining past surveillance

activities or acquiring information about the total number

of activities or intercepts on a particular switch; and

obtaining intelligence information from analysis of billing

records and other business data.

Threats to security originate from both internal and

external sources. Operational components and connections

between the components involved in managing the setup and

control of surveillance activities are particularly

susceptible to intrusion. Telephone companies have been

favorite victims of "hackers" since telecommunication

networks became "computerized." Abuses by hackers have been

aimed at switch elements, support billing, and other record-

keeping functions.

Notwithstanding the concern for potential outside hackers,

the internal security threats from intentional or careless

breaches in security by telephone company employees, or

contractors to service providers, may be a greater threat.

There are several categories of security risks:

o Disclosure of Information: Information about a specific

surveillance may be obtained by an unauthorized individual,

e.g., that a wiretap is being initiated on a specific

target, or information gathered from the wiretap, might be

made available to an outside individual. Even operational

information about the number of surveillances performed at a

single switch or within a service provider's area is

considered to be sensitive information.

o Redirection of Information: There is a risk that

intercepted information might be accidentally sent to the

wrong location, or that it might intentionally be diverted

to another location, or destroyed.

o Manipulation of Information: Data transmitted to and

received by law enforcement officials must be reliable. No

doubt about its association with the intercept target and

the integrity of the information can exist if it is to be

accepted as evidence by the Courts. Neither intentional nor

unintentional manipulation or corruption of the data must

occur.

o Destruction of Information: Information used to control

the establishment of surveillance could be lost or

destroyed, resulting in failure to perform the surveillance.

o Internal Risks from Trusted Personnel: Fraudulent

initiation or termination of intercepts, or disclosure of

intercept information.

There are physical ways to protect the integrity of

electronic intercepts, and ways in which databases and

records can be protected from tampering (logical means of

protection). Physical protection includes:

o control of information to initiate a wiretap to prevent

unauthorized disclosure;

o restricted access at the service provider's facility; and

o physical security in the transmission system and control

points outside the carrier's plant to prevent unauthorized

interceptions.

Logical approaches to protection of data and records

include:

o partitioning databases, switch function, peripherals,

etc.;

o auditing systems to secure the storage and processing of

business records provided to law enforcement agencies in the

course of an intercept;

o controlling access through logging procedures for entry

into the operational components controlling the intercept;

o prohibiting direct remote access through dial-in

procedures to an operational component involved in an

intercept; and

o encryption of data transmitted to the law enforcement

monitoring site to prevent access to the intercepted

information in the course of its transmission from the

distribution point to the law enforcement monitoring site.

FINDINGS AND OBSERVATIONS

The Communications Assistance for Law Enforcement Act was

approved on October 25, 1994. The act is currently in an

early stage of organization, planning, and implementation.

Few conclusions can be reached on a cursory examination of

the progress made over the short period of observation.

Nevertheless, a few indicators are worth noting:

o General Observation: Although the technical complexity of

modifying the existing network and designing features into

new technology that will meet law enforcement's electronic

surveillance needs is not trivial, the industry is highly

competent and capable of meeting the technical challenges.

If major problems arise in meeting the needs of law

enforcement, they will likely arise as a result of

institutional difficulties in dealing with a diverse, highly

entrepreneurial industry made up of a large number of

telecommunications companies offering many new innovations

and features, with the number of players steadily

increasing.

o Timing: There is a possibility that the complexity of re-

engineering and modifying the technology installed in the

current telephone network to meet Law Enforcement's needs

may exceed the time allowed for compliance by the Act.

The Attorney General is to notify the carriers of the

"actual and "maximum" capacities by October 25, 1995

required to meet law enforcement's requirements to bring the

carrier's technology up to specifications. The carriers must

then respond to the Attorney General's notification with

statements of their ability to meet the capacity and

capability requirements within 180 days. Carriers then have

three additional years (four years after approval of the

Act) to comply with law enforcement's requirements (October

25, 1998).

If the Attorney General fails to meet the October 25, 1995 deadline for publis

hing Law Enforcement's capacity notice,

then the service provider's compliance will be delayed

accordingly. If the carriers decide that law enforcement's

requirements are not reasonably achievable within the

allotted time, they can petition the FCC for an extension of

up to two years. This would push back the required

compliance date to as late as October 25, 2000.

There remains a question as to whether there will be

sufficient time for publishing law enforcement's capacity

requirements, completing the ongoing consultative process

between the industry and Law Enforcement, providing

accredited standards bodies with specific input needed to

meet Law Enforcement's requirements, completing the process

leading to accepted industry standards or collaborative

solutions as well as allowing time for switch manufacturers

to engineer and develop the modifications, and

manufacturing, delivering, installing, and debugging the

switch modifications.

Once a clear set of generic specifications is available, it

generally requires two years to develop the software and

hardware to implement a complex set of new features. Simple

modifications may require less time. Adjustment and

debugging of supporting software and operating procedures,

including revising security procedures within the carrier's

operations, may require considerable time and involve a high

level of uncertainty.

The above holds true only for conventional telephone

switches in the service provider's central office. Advanced

Intelligent Networks (AIN), which operate interactively with

software-based computer systems present more complex

problems and a higher level of uncertainty about the

seamless operation without service interruption. As with any

software modification, those for AIN systems are complex,

sometimes tricky, and in the worst case, can bring down a

network if there is a malfunction (malfunctions of this

nature are not specific to AIN, but their complexity makes

them more vulnerable).

Cellular systems present complex operational problems to

handle all hand-offs to other carriers, etc. New modes of

transmission, e.g., PCS, provision of telephone service by

cable television companies, and Asynchronous Transfer Mode

(ATM) fast-packet networks are future technologies that will

allow time for further development without hindering Law

Enforcement's mission.

o Security: The installation of technologies to meet law

enforcement's requirements will place new demands on

carriers to ensure the security of the intercepted

information and of the network at large.

Security of the telephone system is a more serious problem

than news accounts suggest. There is a concerted effort by

the telephone companies to play down security breaches, but

many more have occurred than the public is aware. Anecdotal

evidence in the possession of the carriers indicate that

communication networks (even the Department of Defense) have

frequently been penetrated by hackers. By using debug

routines and "spoofed" passwords (to mimic those with

legitimate privileges) hackers have been able to extract

passwords and personal identification numbers, to make

fraudulent calls and illegal transactions. Others have

maliciously altered databases or extracted personal

information that they were not authorized to have.

Allegedly, there is a black market for surveillance, where

clever hackers can establish surveillance of individuals

from outside the system. Though publicly unconfirmed, there

have been accounts of suspected incidents where hackers have

even intercepted law enforcement communications, including

the contents of wiretaps, although it is highly unlikely

that this has occurred given the complexity of taking such

action. In other instances, intercepts may have been

disconnected from the outside through software switches. It

is also possible for hackers to determine who is being

tapped, which could be of value to the criminal element.

Not all of the security problems originate from the outside.

There have been occasions where telephone personnel, or

manufacturers/vendors technicians, who know the system and

have access from the inside, are motivated to make

fraudulent use of information obtainable from computer-based

databanks.

The security requirements of P.L. 103-414 will require the

industry to tighten its supervision over information

regarding the existence of a wiretap and the identification

of those who are tapped. Furthermore, the content of the

intercepted calls will require protection, since law

enforcement listening (monitoring) posts may be some

distance from the tapped switch (linked by leased or private

lines), with opportunities for others to modify or obscure

the contents or otherwise diminish its integrity as

evidence.

o Safe Harbor: The government may have to make an

affirmative declaration that an "adopted" industry standard

or technical requirement is sufficient to satisfy the "safe

harbor" provisions of the Act.

Section 107(a) of the Act provides that if equipment to meet

law enforcement's requirements is built to meet "publicly

available technical requirements or standards adopted by an

industry association or standard-setting organization,"

vendors or service providers will be considered in

compliance with the Act if the standard or technical

requirements meet the requirements of Section 103 of the

Act. If standards are accepted by an accredited standards-

setting organization, the clear meaning of the Act would

protect carriers and vendors from charges of noncompliance.

However, the Act is ambiguous with regard to what

constitutes "adopted by an industry association." Standards

certified by an accredited standards organization go through

formal processes and orderly steps of approval before being

certified as a standard. "Industry associations," without

standards-setting functions, on the other hand, may have no

formal approval process and operate loosely by consensus

only.

The Electronic Communication Service Providers Committee

(ECSP) is the primary industry-wide body that has dealt with

the requirements of the Act. ECSP is sponsored and provided

administrative support by the Alliance for

Telecommunications Industry Solutions (ATIS). The ECSP is

not an accredited standards setting body as generally

recognized. However, ATIS does sponsor other recognized

standards setting bodies (T1, Protection Engineers Group

(PEG), Standards Committee 05, etc.). Within the ECSP, only

the Cellular Action Team and the Personal Communication

Action Team are coordinating their work on electronic

intercept solutions through accredited standards

organizations. (see footnote 24)

The ECSP committee, however, is only one of many possible

industry groups with the expertise to develop technical

requirements. Any industry organization that tackles the

task would be expected to include the involvement of the of

the FBI's Telecommunications Industry Liaison Unit (TILU) in

its deliberations to ensure that its standards meet the

capability requirements of Section 103 of the Act.

Whether a general consensus reached by ECSP participants or

any other industry organization on technical requirements

would constitute "adopted by the industry" in meeting the

requirements of the Act is unclear. Industry participants in

ECSP have raised questions regarding the official status of

the work produced by the Committee. Thus far, the government

has not responded to industry's concerns in a definitive

way.

If the industry fails to issue technical requirements or

standards, or if it is believed that the technical

requirements are deficient, the FCC is empowered to

establish such requirements or standards if petitioned to do

so by any person or entity. This process could be used by

anyone, including law enforcement agencies, to petition the

FCC to establish an adequate standard.

Continued uncertainty about what constitutes an "adopted"

industry technical requirement could result in future

litigation to decide the question should a cause of action

arise. To avoid the prospect of future litigation and

possible delays, the government might consider a

certification process for standards or technical

requirements that would assure the industry that a technical

requirement that is developed by consent of a nonstandards-

setting association would provide them with a safe harbor

from sanctions for noncompliance.

One option might be to use the authority provided the FCC

for establishing standards under Section 107(b).

Association-approved technical requirements (absent an

accredited standard) could be referred to the FCC for

evaluation and formal adoption.

o Cost Reimbursement: If the Act is to achieve its intent

with regard to upgrading law enforcement's ability to

intercept electronic communications in the existing network

(equipment installed prior to January 1, 1995), then

Congress must appropriate sufficient funds (and the Attorney

General must make them available to the service providers)

to offset the costs of retrofitting. Reliable cost data for

detailed fiscal planning will likely not be available until

the budget period for fiscal year 1996.

Reliable engineering and operational cost estimates cannot

be made until after the Attorney General issues the capacity

requirements that the individual service providers must meet

to comply with the Act. At the time of this report (spring

1995), there have been no decisions on the technology needed

to meet the capabilities for electronic surveillance

required by the law enforcement agencies. Furthermore, the

capacity and specific geographical priorities for

implementing the Act are not scheduled for release until

fall of 1995.

Failure of the government to appropriate and expend adequate

funds to pay the carrier's expenses for complying with the

act will automatically place the carriers in legal

compliance with the act (for equipment installed prior to

1995), but would not result in the deployment of the

technology needed by the law enforcement community in the

timeframe set forth in the Act.

In the event that sufficient funds are not appropriated for

the purpose of offsetting the costs to carriers for

retrofitting pre-1995 equipment, the rate of replacement of

existing equipment with new equipment that would be required

to meet law enforcement's capability requirements would

depend on the business plans of the individual service

providers. Such plans could depend on market strategies, age

and condition of the service providers equipment,

development of new technologies, tax consequences, etc. This

could result in spotty and uneven deployment of new

equipment, with the capabilities and capacity to meet the

Act's requirements (islands of capability), located among

service areas of other providers that continue to operate

old equipment that does not comply with law enforcement's

requirements.

The General Accounting Office (GAO) is mandated by the Act

to compile cost estimates in a report from the Comptroller

General that is due April 1996 and every two years

thereafter. The GAO report is to include "findings and

conclusions. . .on the costs to be incurred by

telecommunications carriers. . .including projections of the

amounts expected to be incurred and a description of the

equipment, facilities, or services for which they are

expected to be incurred." (Sec. 112(b)(2)).

o Future Technologies: Law enforcement agencies will

continually face challenges in maintaining their electronic

surveillance capabilities in the future as new

communications technologies and services are developed.

The field of communication technology is developing rapidly.

A stream of new technologies are qued to complement,

compete, or displace the communications systems of today.

Computer-based packet communications systems, satellite-

based global communications, and the inter-connection of

virtually every form of electronic communication system

through a National Information Infrastructure (NII) will

require law enforcement agencies to keep abreast of these

developments as they come online. Along with the

technological challenges that future systems will bring, are

institutional and international issues that must be

addressed as global communication systems are developed.

*

CHAPTER 1 FOOTNOTES

*

1 For the purpose of this report electronic surveillance is

considered to consist of both the interception of

communications content (wiretapping) and the acquisition of

call identifying information (dialed number information)

through the use of pen register devices and through traps

and traces.

2 Pen register is an antiquated term. It stems from the

manner in which the digits in a phone number were recorded

when telephones used pulse dialing technology, which has

since been replaced by touch-tone technology. The term still

applies to the recovery and recording of the dialing

information that addresses a call to and from an intercept

subject. Authority for initiating a pen register or trap and

trace surveillance is found in 18 USC 3123.

3 Omnibus Crime Control and Safe Streets Act of 1968, Pub.

Law No. 90-351, Title III. However, P.L. 90-351 only affects

federal law enforcement agencies. Thirty-seven states have

enacted some form of electronic surveillance laws to govern

law enforcement agencies and courts within the state's

jurisdiction. Many of the states' electronic surveillance

statutes are more stringent than the 1968 Federal Act. The

remainder of the states do not sanction wiretaps by their

law enforcement entities.

4 On Aug. 11, 1994, Hazel E. Edwards, Director, Information

Resources Management/General Government Issues, U.S. General

Accounting Office, testified before the House Subcommittee

on Technology and the Law, and the House Subcommittee on

Civil and Constitutional Rights, stating, ". . .it is

virtually impossible to precisely estimate the reimbursement

costs discussed in this bill because costs will depend on

evolving law enforcement requirements." After careful study

of the technological and operational factors involved in

meeting the requirements of the Act, and with information

provided by the telecommunication industry and the law

enforcement agencies in the course of compiling this study,

OTA reaffirmed the findings and conclusions of GAO in this

regard.

5 The General Accounting Office (GAO) is assigned the

responsibility under P.L. 103-414 (Sec. 112(b)(2)) provide

cost estimates of the expenditures expected by the

telecommunication carriers to comply with the requirements

of the Act. The Comptroller General is to report to the

Congress by Apr. 1, 1996, and every two years thereafter,

progress for compliance with the Act and projections of

future costs expected to be incurred.

6 See 18 U.S.C. 2518(4). The amendment requires the service

provider "furnish. . .information, facilities, and technical

assistance necessary to accomplish the interception. . ..."

The amendment further provides that a cooperating service

provider ". . .be compensated. . .for reasonable expenses

incurred in providing such facilities or assistance."

7 In 1970 the Ninth Circuit Court of Appeals found the 1968

Act did not provide the necessary statutory authority of law

enforcement agencies to compel the telephone companies to

assist in wiretaps. (Application of the United States, 427

F. 2d 639 (9th Cir. 1970).

8 A Common Carrier is a company that furnishes public

telecommunications facilities and services, e.g., a

telephone or telegraph company. A Common Carrier cannot

control message content.

9 The Congressional Budget Office (CBO) projected that

outlays for the $500 million authorized by the Act would be

$25 million for FY 1995, $100 million for FY 1996, and $375

million for FY 1997. Senate Committee on the Judiciary,

Report on S.2375, The Digital Telephony Bill of 1994, Report

103-402, p. 33, 103d. Cong., 2d sess., Oct. 6, 1994.

10 If the Attorney General decides to pay the costs for

modifications made after Jan. 1, 1995, that are determined

to be not reasonably achievable, the government is obligated

to pay the carrier only "for the additional cost of making

compliance with the assistance capability requirements

reasonably achievable." [emphasis added]

11 Id., CBO estimates that additional authorizations of $100

million will be required for each of the fiscal years 1998,

1999.

12 Section 301 of the Act added Section 229 to the

Communications Act of 1934 by directing the FCC to convene a

federal-state joint board to recommend appropriate changes

to the FCC's separations rules. Regulated carriers will seek

to recover costs through rate adjustments at the state

level, and unregulated carriers will likely pass the costs

to the customers.

13 Testimony of Louis J. Freeh, Director, Federal Bureau of

Investigation, before the U.S. Senate, Committee on the

Judiciary, Subcommittee on Technology and the Law, and the

U.S. House of Representatives, Committee on the Judiciary,

Subcommittee on Civil and Constitutional Rights, Mar. 18,

1994, 103d Cong., 2d sess.

14 The FBI's "Requirements" Document is in its fourth

revision. The second revision was June 1994 (at that time it

outlined nine requirements), the third revision (rev. 2.1),

made Dec. 6, 1994, keyed the Law Enforcement's requirements

to the organization of the 1994 Act, and combined the nine

requirements into four in order to parallel the organization

of the Act. The most recent revision was issued in May 1995.

15 Alliance for Telecommunications Industry Solutions

(ATIS), 1200 G Street, N.W., Suite 500, Washington, DC

20005. Other industry associations have also been

instrumental in developing the working relationship between

the law enforcement agencies and the industry, including

United States Telephone Association (USTA),

Telecommunications Industry Association (TIA), and the

Cellular Telecommunications Industry Association (CTIA), and

other industry standards-setting bodies.

16 ECSP does not include all of the industry groups involved

in compliance with the Act. Many accredited standards-

setting organizations and other trade organizations will

play a role meeting technical and operational compliance

requirements. One example of this is the Telecommunications

Security Association (TSA); an association of security

officials from the service providers that are responsible

for executing authorized wiretaps for their respective

companies. Individuals from this organization are involved

in the ECSP effort, however.

17 This section of the report relies heavily on the material

contained in the document "Law Enforcement's Requirements

for Electronic Surveillance," May 1995 revision, pp. 2-14,

Federal Bureau of Investigation, Washington, D.C. It should

be noted that these requirements represent the law

enforcement agencies' interpretation of the requirements

under the Act. Some service provider's disagree with some of

the interpretations presented in the FBI requirements

document cited above.

18 The number of simultaneous intercepts that a particular

switch or system can accommodate is referred to as

"capacity."

19 "Transmission path" refers to connection or link from a

subscriber's terminal to the network. The path may be over a

wireline or radio link.

20 According to industry representatives participating in

the ECSP, current network signaling can provide the original

calling number, the original called number, and the last

redirected number. It is not considered to be

technologically feasible with existing standards for

interswitch signaling to provide more than this unless the

entire signaling system is changed to provide these

capabilities.

21 "Call content" refers to any type of electronic

communications sent by or sent to the intercept subject,

including transfer of signs, signals, writing, images,

sounds, data, or intelligence of any nature.

22 Section 301 of the Act also directs the FCC to establish

rules to implement Sec. 105.

23 The recent arrest of Kevin D. Mitnick, a well-known and

previously convicted computer hacker, for computer crimes,

points to the problem confronting computer and telephone

networks at the hands of talented and skillful computer

criminals. It is alleged that Mr. Mitnick broke into

computer networks and stole files and acquired 20,000

credit-card numbers by tampering with a telephone switch in

a cellular service provider to reroute his calls to evade

surveillance. John Markoff, New York Times, p. 1, Thursday,

Feb. 16, 1995, John Schwartz, Washington Post, Sunday, Feb.

19, 1995, p. 1.

24 The Standards Organization for Cellular Technologies is

designated TR45. TR46 covers PCS technologies. Both

standards groups operate under the aegis of the Telephone

Industry Association (TIA).

BOX 1-A: Procedures for Establishing a Lawful Wiretap

Legal Authority

The Fourth Amendment of the U.S. Constitution protects

Americans against unreasonable search and seizure by the

government. Each intrusion into the private lives of U.S.

citizens by government entities must fit within the limits

prescribed by the U.S. Constitution as interpreted by the

U.S. Supreme Court.

The evolution of the telephone system and wiretapping is one

of the best examples of where technological development

continues to challenge the Court and the Congress in

balancing personal rights with public needs. In 1928, the

Supreme Court first confronted the issue of whether wiretaps

constituted "search" or "seizure under the Constitution.

(Olmstead v. United States, 48 S. Ct. 564, 277 U.S. 438) In

the instance of Olmstead, the Court found that tapping a

telephone did not violate the Fourth Amendment. The case is

best known, however, for the dissenting views of Justice

Brandeis, who argued that wiretaps without a court order or

warrant violated a person's right of privacy, which he

defined as "the right to be let alone--the most

comprehensive or rights and the right most valued by

civilized men." At the time of the Olmstead decision there

were no wiretap statutes.

The Congress attempted to deal with the issue in the

Communications Act of 1934. Siding with Justice Brandeis'

views, the Congress included in Section 605 of the Act the

provision that "no person not being authorized by the sender

shall intercept any communication and divulge or publish

[its] existence, contents...or meaning." A series of cases

followed passage of the 1934 Act, which interpreted various

technical aspects of the law dealing, e.g., the

admissibility of evidence, interstate and intrastate

distinctions affecting the law, and individual rights of the

called and calling parties.

By 1968 the provisions of the Communication Act of 1934

dealing with wiretapping were so muddled by interpretations

of federal and state courts that the Congress decided to set

forth a process and delimit the legal authority of the law

enforcement community's authority to conduct wiretaps under

Title III of the Omnibus Crime Control and Safe Streets Act

of 1968. The procedures set forth in the 1968 Act define the

authority and guide the conduct and procedures of wiretaps

by federal law enforcement agencies. Thirty Seven states

have enacted parallel state statutes that define wiretapping

authority within their jurisdictions. Many of the states

have laws more restrictive than those governing the federal

authorities.

Telecommunications and computing technology continued to

develop, so the Congress found it necessary to enact the

Electronic Communications Privacy Act of 1986, which amended

the Omnibus Crime Control and Safe Streets Act of 1968 by

broadening its coverage to include electronic communications

(to include electronic mail, data transmissions, faxes, and

pagers). The provisions of Title III of the 1968 Act, as

amended, continue to govern the procedures for obtaining

legal authority for initiating and conducting a lawful

interceptions of wire, oral, and electronic communications.

Procedure for Obtaining Court Order

It is more involved for law enforcement officials to obtain

authorization to initiate and conduct a lawful wiretap than

it is to obtain a search warrant. A normal search warrant

requires only that a law enforcement official apply directly

to a federal magistrate. Title III requires that a wiretap

order be approved by the Attorney General, the Deputy, or an

Assistant Attorney General of the Department of Justice

before forwarding to a local U.S. Attorney for application

to a federal district court or other court of jurisdiction.

Electronic surveillance is only authorized for specific

felonies that are specified in the Act, e.g., murder,

espionage, treason, kidnapping, bribery, narcotics,

racketeering, etc.

Applications for electronic surveillance must show probable

cause set forth in specific terms. It must also be shown

that the use of other normal investigative techniques can

not provide the needed information, or that they would be

too dangerous. The information in an electronic surveillance

application must specifically state the offense being

committed, the place or telecommunications facility from

which the subject is to be intercepted (special provisions

are made for "roving" interceptions where the subject may be

highly mobile), a description of the types of conversations

to be intercepted, and the identities of the person or

persons committing the offenses and who are the subjects of

the intercept. Thus, the Act focuses on obtaining hard

evidence to be used in prosecution, rather than general

intelligence

Court orders are normally valid for 30 days. Judges may also

require periodic reports to the court advising it of the

progress of the interception effort. A court may extend the

order for an additional 30 days if justified. Federal

district court judges can authorize electronic interceptions

within the jurisdiction of the court where he or she

presides. If the intercept subject is mobile or is using a

mobile communications device a judge may authorize

electronic surveillance throughout the United States

wherever the subject may travel. A judge actually issues two

orders: one authorizing the law enforcement agency to

conduct the interception; the second directing the service

provider to set up the intercept, specifying the telephone

numbers to be intercepted and other assistance to be

provided.

Under "emergency situations," e.g., serious and life-

threatening criminality as defined in the Act, the Attorney

General and others specified in the Act, can authorize and

emergency electronic surveillance that if valid immediately,

but application for a court order must be issued within 48

hours. If a court does not ratify the action and issue an

order the intercept must be immediately terminated.

Emergency intercepts are rarely initiated.

Preserving Privacy and the Integrity of the Evidence

Intercepted communications are required to be recorded in a

way that will protect the recording from editing or

alterations. Interceptions are required to be conducted in

such a way as to "minimize the interception of

communications not otherwise subject to interception." This

included unrelated, irrelevant, and non-criminal

communications of the subjects and of others not named in

the order.

Upon expiration of the intercept order, or as soon as

practicable, the recordings are presented to the court of

jurisdiction and are sealed. Within a reasonable time period

after interception, the subjects must be furnished with an

inventory of the recordings, and upon motion, a judge may

direct that portions of the recordings be made available to

the subject for inspection.

Should the law enforcement agency err in conducting the

electronic surveillance as authorized in the court order,

the intercept may be challenged, and if found to have been

illegally conducted, the evidence in the intercept may be

suppressed.

SOURCE: Title III of the Omnibus Crime Control and Safe

Streets Act of 1968.

Chapter 2: Technical Aspects of Electronic Surveillance

*

ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

*

TECHNICAL ASPECTS OF ELECTRONIC SURVEILLANCE

The evolution of the modern telephone system, from its

invention in 1876 followed a predictable path of development

until digital technology and optical fiber began seriously

supplanting analog technology and copper wire in the U.S.

telephone system. Since about the 1970s the technology of

electronic switching, digital processing, computer

architecture, and optical transmission have progressively

developed into commercial devices and applications whose low

costs and broad capabilities have made these technologies

the foundation of a new era of communications. (see

footnote 1)

The speed with which the nation's communication system is

shifting from a wire-based analog system to digital

computer-controlled switches and optical fiber is

astounding. In 1989, nearly one-half of the major telephone

companies' switches were digital. By 1993 the proportion of

digital switches had grown to 80 percent. (see footnote 2)

Fiber optic transmission systems also are rapidly displacing

copper in local service and long distance carriers. In 1985,

long distance carriers had about 20,000 miles of fiber optic

cable in service. By 1993 the long distance companies

reported slightly more than 99,000 miles of optical fiber.

(see footnote 3) Local telephone companies had about 17,000

miles of optical fiber installed in 1985, and this grew to

over 225,000 miles by 1993. (see footnote 4)

The recent explosion of wireless communication has extended

mobile service to more than 734 metropolitan and rural

service areas. These service areas geographically overlay

the wired telecommunication systems to which they

interconnect. Currently, there are over 1,100 cellular

switches in operation in the United States. (see footnote

5) The growth of wireless communication has been remarkable.

Today, there are more than 16 million cellular subscribers,

and the cellular industry estimates that subscribership will

double by 1998. (see footnote 6) Following behind is the

next generation of wireless services, the new Personal

Communication Services (PCS), which are similar in function

to today's cellular communication services, but new PCS

entrants may develop entirely new services in the future,

which could present different problems to law enforcement

agencies. Coming next will be satellite- based

communications systems for personal communication that could

extend wireless communication to nearly every quarter of the

world.

In addition, a convergence of digital and analog

technologies is bringing other nontraditional sectors of the

communication industry into what once was the domain of the

telephone companies. Government deregulation and industry

restructuring has the potential for further blurring the

business lines between the cable television industry andthe

telephone carriers, and has raised the prospect that

electrical utilities might someday be competitors in the

telecommunications market as well. (see footnote 7)

Through the 1950s and into the 1970s law enforcement's

wiretap requirements were easily met. The nation's telephone

system largely consisted of twisted copper wires that

connected subscribers to central office switches that routed

the calls to their destinations through copper cables or

overland via microwave radio, and later satellites. The

transmitting and receiving instruments were commonly used

telephones. Business may have had Private Branch Exchanges

(PBX) to route their calls. But in general, it was a

comparatively simple system of wires connected to switches

that connected to other wires that routed the calls to

businesses and residences. Law enforcement officials, armed

with the necessary legal authorization, would simply

physically connect "alligator clips" to wire terminals and

monitor the contents of calls coming to and going from the

telephone line authorized in the wiretap order. (See figure

2-1.) Since much of the system was under the control of

American Telephone and Telegraph (AT&T), although GTE and

other independent telephone companies operated as well, the

national system was largely based on the same standards,

operating protocol, and equipment design used by AT&T.

In the recent past, additional complexities were added to

the system when transmission technologies for the copper-

based analog system were developed to provide more

bandwidth, and hence speed, to handle larger volumes of

calls. A transmission mode referred to by its industry

standards name, "T1," and a faster version "T3," which was

originally developed for intrasystem high-speed trunking,

became available for high-volume users, largely businesses.

This technology gains its speed by separating the electronic

signal into discrete segments divided sequentially in time

(Time Division Multiplex, or TDM) and routing them

sequentially over the line to be resequenced at the receiver

(demultiplexed). In this way the signals are virtually

routed over channels so that many more bits of information

can be transmitted over the wire or coaxial cable at the

same time.

Multiplexing can increase the normal speed of transmission

from thousands of bits per second (kbs) to 1.544 million

bits per second (Mbs) for T1 and 45 Mbs at the T3 rate.

Because multiplexing breaks the continuity of the signal in

the transmission phase, it places an additional degree of

difficulty for electronic surveillance. Also, since 1984,

long distance carriage has been separated from the local

exchange carrier, so that now an intercepted call might flow

among several different carriers on its way to or from a

target. (See figure 2-2.)

The current telecommunication environment is considerably

more complex. Wireless technology has expanded the reach of

the telephone system. The combination of digital

transmission, imbedded computer databases, digital

switching, and the increased speed of optical fiber cables

provide many more functions, options, and flexibility. As a

result, many of the functions and operations, which were

once the sole province of the telephone operating companies,

are now performed directly by the subscriber, sometimes

without the knowledge and control of the carrier. Wide-area

centrex operations, for instance, allow a large business

subscriber to manage a communication system within the

carriers network, but independent of the carrier with regard

to assigning internal number, call routing, and location

identification--a virtual network within the carrier's

network. Wireless subscribers may roam outside their home

service area. Features such as call forwarding, speed

dialing, call transfer, and specialized high-speed computer-

based services add complexity to the problems of wiretapping

for law enforcement agencies. (See figure 2-3.)

The future operating environment will contain several

additional actors than are now present in the

telecommunication network. Personal communication service

providers (PCS) will extend the reach of wireless

communication adding more flexibility, mobility, and more

features than are now offered by cellular communications.

Future satellite communications systems will operate

globally, which raises the prospect of international call

forwarding or other features that will confound the job of

law enforcement officials in fighting international criminal

transactions.

Fiber cables will likely be extended to the home as new

construction replaces the old, and prices of pulling fiber

in old construction come down as a result of improved

technology. There will be added incentives for the local

telephone companies to extend fiber from the curb to provide

video on demand and to meet the challenge of the television

cable companies (CATV) as competitors for the home telephone

market as well. It is nearly certain that many more

innovative features and functions will be developed based on

the infinite flexibility of computer-based switches and

information systems.

Should the vision of the National Information Infrastructure

be realized, the nation's communication system will be

transformed into a seamless mix of all modes of

transmission--voice, video, image, facsimile, and data--

flowing as an admixture of digital babble traveling at

speeds approaching the speed of light. It is assured that

law enforcement's difficulties in keeping up with technology

to maintain its wiretap capabilities will be a continual

struggle in the future. (See figure 2-4.)

New features, functions, and options will continue to be

developed and offered to subscribers. The potential and

flexibility of Advanced Intelligent Networks (AIN) have not

yet been seriously scratched on the surface. Applications

are only limited by the imagination of the systems engineers

and developers and the acceptance of the new applications in

the marketplace. Faster transmission systems and computer

networking will lead to advanced systems that can leverage

the bandwidth into currently unforeseen applications. The

vision of a National Information Infrastructure (NII), if

realized, could unleash a diversity of new services based on

computer mediated multimedia communication far different

from the current communication paradigm. A diverse offering

of features and services is currently available on the U.S.

telephone network, and this list will grow as time passes.

(See table 2-1.)

TECHNOLOGIES

Each of the technologies or features listed in table 2-1

requires a technical modification or solution to meet the

requirements of the Act. Some solutions may be easily

achieved through software programs or minor hardware

modifications. Other modifications will require redesign or

re-engineering, or perhaps significant development efforts

to meet law enforcement's needs. Some of the technologies

listed in table 2-1 are already deployed throughout the

national system. Others are installed or offered by some

service providers and not by others, and sometimes carriers

may be using different (incompatible) standards to drive or

manage the same generic technology. Still other technologies

are just emerging into a commercial stage of development and

have not yet been widely adopted or deployed by the

industry.

One such developing technology is the Asynchronous Transfer

Mode (ATM) of transmission, which is considered by many in

the telephone and computer networking industry to be the

chosen technology for building the backbone of the next

generation of telecommunication networks. This technology

would radically change the characteristics and operation of

the network by integrating voice, video, and data into the

operating system. It offers phenomenal speeds (rate of

information transfer), potentially up to billions of bits

per-second range (gigabits). ATM is able to carry traffic

originating from many different kinds of networks that will

make up the National Information Infrastructure of the

future.

Other digital network technologies are based on the

transmission of information packets (frames or cells) that

route segments of the information string (a voice message,

an image, or data) to individual addresses within the

interconnected network in a so-called "connectionless" mode.

This is the transmission mode used on the Internet. Packets

for an intended recipient may take a number of different

routes to reach a destination, depending on the traffic

congestion on the network and other network management

factors.

Each new technological development presents the industry and

law enforcement with a challenge to maintain parity for

electronic surveillance in a fast- changing communication

environment. The combined efforts and collaboration of the

industry and the law enforcement agencies will likely be

required on a continual basis for the foreseeable future as

the nation's communication infrastructure undergoes a nearly

complete metamorphosis.

The industry/government joint activities within the

Electronic Communication Service Providers (ECSP) committee

discussed in chapter 1 is addressing the practical matter of

adapting the telecommunication industry's installed

equipment base to comply with the Act. This, in its self, is

a substantial and expensive task, but the technological

challenges presented by the emerging network technologies,

and technologies still in a conceptual stage, will be

waiting to be solved when the immediate task is finished.

The ECSP committee has divided the technologies of immediate

concern, i.e., switch-based solutions, advanced intelligent

networks (AIN), mobile cellular communications, and personal

communication services (PCS). The action teams are

supplemented by others that deal with the interfaces between

the carriers equipment and the law enforcement agencies, and

one that considers the implications of future technological

developments.

SWITCH-BASE SOLUTIONS

The function of a switching system is to interconnect

circuits. It is the preferred point of access for electronic

surveillance by the law enforcement agencies. A switch-based

solution is an approach to meet law enforcement's electronic

surveillance requirements using the traditional central

office switch as the point in the network where access to

the intercept target's communication is achieved.

There is estimated to be more than 20,000 land-line switches

installed and operating in the United States today. (see

footnote 8) Approximately 1,200 of these switches are of a

special kind that support Integrated Services Digital

Networks (ISDN), a channelized communication mode that

serves the needs of some business customers and a fewer

number of residential subscribers with special needs. ISDN

separates the signaling information from the call content

information, which increases the speed and flexibility of

communication. It also increases the complexity of

wiretapping. Integrated Services Digital network switches

are being considered as part of the Switch-Based Solutions

Action Team.

Switch Technology

The 20,000 switches in service today are a mixture of old

and new technology. A few rural areas still have vintage

1900 step-by-step (SXS) electromechanical switches in their

networks, although they are being quickly phased out. Some

electromechanical crossbar switches from the late 1930s

still exist on the network. The electromechanical switches

remaining pose no problem to law enforcement because their

technology is simple, they are largely located in rural

areas, they do not provide flexible calling features, and

they are being replaced by modern switches rapidly.

Modern electronic central office switches are able to

provide a vast number of switch features and services.

Electronic switches are based on either analog or digital

technology. Analog Stored Program Control Switches (Analog-

SPCS) were introduced in the mid-1960s, and became the

mainstay for metropolitan switches in the 1970s and `80s. A

large number of Analog-SPCS remain in service, but they are

being replaced by digital electronic switches. Digital- SPCS

were introduced in the early 1980s. There is a large number

of Digital- SPCS in the national network, and their number

is growing. These electronic switches are largely

manufactured by four manufacturers: AT&T, Ericsson, Northern

Telecom, Inc., Siemens Stromberg-Carlson.

A number of other type switches provide functions and

services in addition to the circuit switches listed above.

These include Packet Switches, Private Branch Exchanges

(PBXs), Broadband Switches, Cellular Switches, and Personal

Communication Services (PCS) switches. Among the ECSP Action

Teams, Cellular and Personal Communication Services are

being dealt with separately from Switch-Based Solutions in

the central office. On balance, Packet Switches, PBXs, and

Broadband Switches, while they will be more important in the

future, do not figure as prominently in the network at this

time, thus they present a lesser immediate practical problem

for law enforcement, and are not directly addressed in the

Act.

There are two major categories of switches: local and

tandem. A local switch connects one customer's line to

another customer's line, or to a connection (trunk) to

another switching system. A tandem switch connects trunks to

trunks. A third category of switch--remote switches--are

local switches where a portion of the switch and some switch

software is located away from the main or host switch. Host

switches can serve several remote switches, and are

connected to the remote switches with connection links.

Electronic surveillance at the central office switch will

involve local and tandem switches, as well as host and

remote switches.

The major impact that new switching technologies have had on

the network is the emergence of remote digital terminals and

switch modules that terminate the conventional analog

interface nearer the customer and use a digital interface to

other network components.

Features and Functions

Introduction of Analog-SPCS into the national telephone

network nearly 30 years ago brought many new features and

functions to customers. These features (Custom Calling

Services) included Call Forwarding, Speed Calling, Call

Waiting, etc. Since that time, hundreds of more

sophisticated specialized services have been developed as

Digital-SPCS came on line. Many of these have presented

substantial challenges to law enforcement agencies' ability

to conduct court-ordered electronic surveillance.

The features or functions described below present the most

significant challenges to meeting the needs of the law

enforcement community:

Call Forwarding

Allows a subscriber to redirect the incoming calls by

dialing the call forward activation code followed by the

directory number to which the calls are to be forwarded.

This feature can be activated and deactivated at any time

from the subscriber's telephone set.

Electronic switching systems have the ability to redirect an

incoming call to either another directory number within the

same exchange, or to another exchange over a trunk line.

When a call is redirected by the switch, the call content is

not transmitted to the subscriber's line, but instead is

rerouted at the switch.

Speed Calling

Permits the subscriber to link a set of abbreviated

directory numbers (i.e., one number or two-number sets on

the telephone) to the directory numbers (DN) of frequently

called parties at the subscriber's own initiative. This

allows the subscriber to initiate a call by dialing the

abbreviated one or two-digit number. Activation of Speed

Calling is at the central office switch without involvement

of the service provider. Some versions of speed dialing

services permit the subscriber to change the assignment of

directory numbers in real time, i.e., in the course of a

call, or to change the number assignment remotely.

Abbreviated Speed Calling codes created by the subscriber

are accessible to law enforcement agencies from the local

exchange carrier.

Three-Way Calling and Call Transfer

Enables a subscriber to add additional parties to a call

that is in progress. When Three-Way Calling is invoked, the

calling party or the called party temporarily suspends the

conversation, initiates service and connects to another

party, then adds the new party to the initial call. Call

Transfer behaves somewhat as Three-Way Calling, but it

allows the initiator of the transfer to drop off the call

while the remaining parties continue the conversation.

Custom Local Area Signaling Service (CLASS)

Is a set of call management features that provides the

called party with control over incoming calls. CLASS

features are available through both Analog- SPCS, and Digital-SPCS that are eq

uipped to support the Common Channel

Signaling/Signaling System-7 (CCS/SS7) capabilities. CLASS

features place more of the control of the call in the hands

of the called and calling parties. Those features, which

provide the called party more control, generally are enabled

by passing the calling party's number to the terminating

switch as part of the SS7 call setup message. About a dozen

features are available through CLASS services.

Automatic Recall allows the user to activate a procedure by

dialing a code, e.g., *69, that automatically redials the

last incoming call--whether or not the call was answered--

without having to know the caller's number.

Selective Call Forwarding enables a customer to define a

list of telephone numbers and assign each a forward-to

destination number. Incoming number on the list are

forwarded to the assigned destination number. Selective Call

Forwarding, and some of the other CLASS features, provide

the customer with the ability to create, modify, activate,

and deactivate screening lists at will without the

involvement or knowledge of the service provider.

Number Portability

Number portability will allow telecommunications users to

retain their telephone numbers over time, despite moving to

different service areas and physical addresses. Potentially,

users could be assigned a lifetime phone number. The

telecommunications industry is also developing services that

use a nongeographic number to identify a subscriber, such as

AT&T's Follow Me service. Callers can be reached at the

number regardless of their physical location or the type of

terminal equipment used (i.e., home telephone, office

telephone, cellular terminal). The infrastructure to support

these types of services will be deployed over the next

several years.

The availability and use of portable and nongeographic

numbers may have several implications for law enforcement.

Law enforcement will have to be able to determine the

carrier serving the investigation target, that person's

location, and any subsequent carriers and locations involved

in transmitting the communication. Network-based

capabilities to support lawfully authorized interceptions

should be capable of providing dialed number information as

well as translated numbers used by the network for routing

calls to or from the intercept subject.

Integrated Services Digital Network (ISDN)

ISDN provides a broad range of voice, data, and image

services based on digital communication for transport and

control within the network. ISDN is based on combinations of

64 kbs (thousand bits per second) channels (lines) combined

to increase bandwidth, and therefore increase the speed and

capacity of transmission. Information is converted into

digital form within the subscriber's equipment before being

ported to the network. Since everything is in digital form,

all voice and nonvoice information looks the same as it

passes through the system.

ISDN uses a separate 16 kbs digital channel (D-channel) for

signaling, i.e., communication between the subscriber and

the local switch. The D-channel is part of the access line,

but it can be used to carry user-to-user information (e.g.,

packet messages) as well as signaling information.The

subscriber controls the service features by sending messages

to the switch, and the switch responds with messages to the

subscriber over the D-channel.

The functions and signaling for ISDN are processed through a

number of standard interfaces that provide different data

rates (i.e., speed and capacity). The two most common, and

of most concern to the law enforcement agencies, are:

o Basic Access--composed of two 64 kbs B-channels (for

voice, data, or images) and one 16 kbs D-channel for

signaling; and

o Primary Rate--operates at a rate of 1.544 Mbs (million

bits per second), composed of 23 B-channels of 64 kbs each,

and one 16 kbs D-channel for signaling.

With ISDN the subscriber's signals for activating or

deactivating a feature is carried over a separate channel

(D-channel) instead of being carried over the same channel

as the call content, as is the case for Analog-SPCS.

Traditional analog intercept techniques are not compatible

with ISDN.

Configuration of Switch-Based Solutions

P.L. 103-414 requires that intercepted call setup and call

content information be instantaneously available to the law

enforcement agency or agencies at one or more monitoring

site off the premises of a service provider. Each

simultaneous intercept originating from a switch must be

carried individually and be adequately associated

(identifiably linked) with each lawful intercept at an

authorized law enforcement agencies monitoring point. An

intercept target may be the subject of more than one

authorized wiretap by more than one law enforcement agency.

In such cases, both call content and call-setup information

must be routed to both agencies without either knowing of

the existence of the wiretap initiated by the other. This

will require a distribution facility or some other means to

route each intercepted call to each agencies' monitoring

site over a private line or connection. (See figure 2-5.)

An intercept is initiated by a service provider at the

request of a law enforcement agency having legal authority

for the wiretap. The service provider remains in

administrative control of the intercept through an

interface, i.e., a point or connection common between the

service provider's system and the law enforcement agencies

monitoring site. Communication links between law enforcement

monitoring sites and the service provider will establish the

surveillance parameters for routing information and access

to the intercept target's speed-dialing lists and automatic

call forwarding lists without direct control of the switch

interface or the distributor component by law enforcement

officials.

Call information, i.e., call content and call data, is

routed automatically from the target line interface within

the switch that connects the targeted line through the

distributor component to law enforcement monitoring sites

once a lawful wiretap is triggered by the service provider.

The switch and distribution functions in the intercept

configuration shown in figure 2-1 is straight forward for

Plain Old Telephone Service (POTS), but Integrated Service

Digital Network (ISDN) at the basic or primary rates of

service can carry 2 or 23 calls, respectively. Each channel

is considered to be a separate call, therefore simultaneous

processing and routing communications carried over ISDN, and

also multifrequency PBX trunk lines will likely require more

complex solutions.

WIRELESS TECHNOLOGIES

The mobility of an intercept target using mobile cellular

communication presents problems for electronic surveillance

that did not exist a decade ago. Its flexibility and

adaptability for mobile communication, whether on foot, in a

moving vehicle, from a boat, or from an airplane, makes it

an attractive alternative mode of telecommunication for the

criminal element.

There are currently two primary modes of wireless, mobile

communication available to subscribers: Cellular

communications, currently one of the fastest growing sectors

of the telecommunication market, and Personal Communication

Services (PCS), a developing form of wireless communication

with similarities to cellular, but with differences in

operations that may present unique wiretap problems to law

enforcement as special features are developed. A fourth

communication system in the conceptual stage of development

uses satellite-based technology for long-range

communications over broad geographic areas. When

operational, satellite systems will increase the complexity

of electronic surveillance by the law enforcement agencies,

since they will be capable of transnational and global

communication (portending possible problems with

international transfer of information or data). Furthermore,

these systems may employ space-based switching and hand-off

technology that places the control center for communications

in remote reaches of orbital space instead of secure,

controlled operation accessible directly on land.

Mobile Cellular Technologies

Wireless cellular service covers 306 metropolitan areas and

428 rural service areas. Two cellular service providers are

licensed to offer service within each service area. One of

the service providers is the local telephone company serving

that area (e.g., Southwestern Bell for example), and the

second is a non-wireline company (e.g., McCaw for example).

These providers use multiple cell sites (supra) and one or

more mobile switch carriers (MSCs), depending on customer

demand. Reseller providers exist, i.e., those who lease and

retail capacity and services from other providers, but they

largely depend on the facilities of the primary service

providers.

Cellular service allows a subscriber to move freely within a

defined cellular service area centered around a cell site

(each cell ranges between one and 20 miles in diameter). If

the subscriber moves into an area serviced by a different

cell site that is within the service provider's service area

(Intrasystem Roaming), (see footnote 9) the call control

may be passed to a new MSC. (see footnote 10) If the user

activates the mobile unit out of his or her home area

(Intersystem Roaming), information about the user (MIN, ESN,

authorized services, billing, etc.) is exchanged between the

original (home) service provider's Home Location Register

(HLR) and the Visited Location Register (VLR).

The main elements of a cellular network include:

1. cell sites that provide the radio frequency link

between the mobile user and the cellular network; and

2. Mobile Switching Center (MSC) that performs call

switching and routing, and external connections to other

networks (e.g., local exchange carriers and interexchange

carriers). (See figure 2-6.)

Each cell antenna facility is connected either by wireline

or microwave radio to the MSC. (see footnote 11)

Cellular radio communication may be either analog or

digital. The radio components of most of today's cellular

networks are analog-based, but many of the carriers are

slowly switching from analog systems to digital systems in

order to increase the capacity, offer a wider choice of

services, reduce fraud, and improve security.

Frequency Modulated (FM) radio channels are currently used

for voice communication and control (call supervision and

handoff) (see footnote 12) from the subscriber's telephone

to and from the receiving radio at the cell site of the

service provider. Control channels relay control information

between the MSC and the mobile unit. Control channels are

used during call setup to transmit dialed digits and the

mobile unit's Mobile Identification Number (MIN) and

Electronic Serial Number (ESN).

The analog signal received at the cell site is converted to

digital form and transported to MSC over multiplexed

channels of T1 or T3 land lines or digital microwave radio

systems. The multiplexed signals contain voice or data

communication, and information about the user (e.g., MIN and

ESN) and the dialed digits (Directory Number) needed to

complete the call.

Once a call has reached a MSC, the connection to its

destination is handled as any call placed on a land line

through a local exchange carrier end office. Based on the

number called, the MSC connects the caller through:

o a wireline local exchange carrier switch;

o an interexchange (long distance) carrier point of

presence (a connection point between long distance carriers

and the local exchange);

o a MSC outside the service provider's service area; or

o another mobile subscriber within the same MSC.

A call may pass through several switches and facilities of

many service providers before reaching its destination.

Although cellular networks are similar to the line-based

local exchanges in some ways, they function differently in

others. In a cellular system, subscribers control access and

selection of services ( e.g., activating, answering,

addressing) by sending and receiving control messages from

the mobile unit over the control channel to the MSC. The MSC

receives and decodes the information from the control

channel, identifies the user ( from the MIN transmitted by

the mobile unit), and activates the services, features, and

restrictions associated with the subscriber's MIN. After the

preliminary setup information is processed by the MSC, a

connection to the Public Switched Telephone Network (PSTN)

is established and the dialed digit information (Directory

Number, etc.) is relayed to the next switch or connect point

in the PSTN. The MSC then monitors the control channel from

the mobile unit and awaits further control signals that

indicate a request for disconnect, movement to another cell,

or activation of a feature, e.g., three-way calling.

Configuration of Cellular Solutions

P.L. 103-414 does not address technologies for intercepting

the radio transmission associated with the operation of a

cellular system. The preferred point of access for a lawful

interception by the law enforcement agencies is at the MSC.

The requirements of the law enforcement agencies under the

Act focus on switch-based technology at the MSC and

relational databases that interact with the MSC.

Some cellular switch manufacturers have developed

capabilities within their switches to accommodate some of

the needs of the law enforcement community for lawful

intercepts. The requirement under P.L. 103-414 to support

multiple, simultaneous intercepts may, however, overtax the

intercept capabilities now built into MSC switches. (see

footnote 13) The capacity to accommodate multiple intercepts

is determined by the number of electronic intercept access

ports designed in the MSC switch. Switch manufacturers are

working on modifications to overcome port limitations, but

in some cases physical limits of space within the switch

will limit the number of access ports that can be added.

Switch design was based on the anticipated increase in

capacity needed for subscriber growth. Law enforcement

agencies' need for increased capacity for electronic

surveillance was not hitherto considered in switch

specifications.

Call Setup Information

As is the case with landline telecommunications, law

enforcement agencies require access to line information for

all completed and attempted calls, including calls forwarded

to another number or voice mail, unanswered calls, and call

waiting calls. Such information includes: The cellular

intercept subject's Mobile Identification Number (MIN) and

Electronic Serial Number (ESN), and the calling party's line

information when delivered to the MSC that is being tapped.

Call setup information for calls originated by a cellular

intercept target must include all digits dialed by the

subject (e.g., Directory Numbers, speed dialing, etc.),

billing record information, and signaling information used

to establish or redirect call flow (e.g., activating service

features). During the course of originating a call,

signaling information is carried over the control channel to

the MSC. (see footnote 14) After connection is made with

the called party (cut-through), subsequent dialing

information from the target's mobile unit (e.g.,

pulses/tones representing digits, voice dialing, etc.),

including information generated by the subject in response

to system queries, travel over the bearer channel (call

content channel). The call management information

transmitted on the bearer channel is not interpreted by the

switch, and therefore is not available to the law

enforcement agency in the call setup messages. This

information is in the form of audible tones or voice

information commingled with call content.

Call Content

Law enforcement agencies require access to cellular call

content of the intercept target's terminal, including voice,

voice band data, and paging/short messages. (see footnote

15) Access to call content must be provided by the cellular

service provider for calls originated or terminated to the

intercept target's mobile number, including mobile-to-mobile

calls, mobile-to-wireline calls, and wireline-to-mobile

calls. All of the custom calling functions invoked by the

subject, e.g., call forwarding, voice mail, three-way

calling, call waiting, etc., must be accessible while the

service provider maintains access to the call.

For redirected calls, access is required from the time that

the bearer (call content) channel to the target (either the

primary called number or to a redirected number) is

established, until the call to the forwarded-to target is

released. If access to the communication cannot be

maintained, the cellular service provider is required to

provide the law enforcement agency with information that

will enable law enforcement to determine the new service

provider's area, whether landline or cellular. Law

enforcement agencies would prefer to have access maintained

by the cellular service provider for three- way call for the

duration of the call whether or not the intercept subject's

call is dropped. Industry technicians are not sure that this

is feasible in a cellular system.

Mobility

Cellular service providers are to provide continuous access

to all ongoing calls, so long as the carrier maintains

access to the call, regardless of the number of handoffs

that may occur, whether intra-cell, intra-MSC, or inter-

MSC. Inter-MSC handoffs include: handoffs within a service

provider's area when more than one MSC serves an area;

handoffs between different service areas operated by the

same service provider; and handoffs between different

service areas operated by different service providers. The

intercept must be maintained regardless of how many

intervening handoffs might occur. After handoff, law

enforcement agencies require access to information

identifying the visited service area and the new service

provider's identification so that a lawful authorization

(secondary carrier assistance order, which is derived from

the original court authority) for intercept information in

the new service area under the control of the second or

successive carriers can be obtained.

Roaming

When roaming outside of the home service area, law

enforcement requires access to all calls initiated or

received by the subject if the visited service provider has

received a lawful request to activate an intercept, and

arrangements have been made for delivery of the information

to the law enforcement monitoring site. The visited service

provider has no legal obligation to intercept a cellular

target's calls once the subject moves out of its service

area unless it is a call in process (supra). The home

cellular service provider is required to provide access to

any call setup information or call content if access is

maintained in the home area during call delivery to a

roaming subject.

Registration Information

When a mobile intercept subject roams into a new service

area, activates his or her mobile unit, and requests

service, the home service providers Home Location Register

(HLR) exchanges information with the new cellular service

provider's Visiting location Register (VLR). When this

occurs, law enforcement agencies require information on the

identity of the new service area requesting the registration

information. Law enforcement must then obtain a lawful

authorization to access the call content and call setup

information from the visited service provider.

Service Site Information

Law enforcement agencies in possession of the proper Title

III court authorized electronic surveillance order (P.L. 90-

351, Sec. 801 et. seq.) or an enhanced pen register (see

footnote 16) (but not under law enforcement's pen register

or trap and trace authority) may ask a service provider for

detailed service site information regarding an intercept

target's location. For example, a carrier provider may be

required to deliver information identifying the cell site

from or to which service is being provided, the cell sector,

or analog radio frequency power levels coming from the

intercept subjects terminal (a measure of distance from the

receiving cell's antenna), the identity of the service area

supporting communications after a handoff, and other

geographic information available, including the subject's

physical location if known.

Cellular Intercept Functions

The functions for intercepting electronic communications in

the cellular environment parallels that used for landline

switches (supra), but may require different architectures.

However, setting up a call and managing it in the course of

cellular communications will involve several steps, some of

which are not used in landline switches, e.g., activation,

registration/deregistration, and call handoff.

A service provider that controls a subject's HLR must

identify and somehow set a flag within the subject's service

profile to indicate that intercept processing is required at

the MSC. If the intercept subject is visiting another

service area of a cellular carrier that has been lawfully

requested to initiate an intercept, the visited service

provider may tag the subject (a temporary tag) within the

VRL to indicate that information processing is needed when

the subject activates services within its area. (see

footnote 17)

The lawful intercept request to the cellular service

provider will typically call for:

o Intercept Subject Identifier (MIN),

o requesting law enforcement agency's name or numerical

identifier,

o the law enforcement agency's monitoring location (line or

identifier), and

o authorization and access information (e.g., service

provider's personnel authorized to access or change

intercept data).

Law Enforcement Access

Call setup information, signaling data, handoff information,

call forwarding, call waiting, call content information,

etc., will be transmitted in real time, or as soon as

possible, to the law enforcement monitoring site. Call setup

information (i.e., MIN, ESN, called or calling number, date,

time, and available location information) may be transmitted

over the signaling channel of law enforcement's monitoring

line.

Personal Communications Service (PCS)

The Federal Communications Commission (FCC) is currently in

the process of auctioning a 160 Megahertz portion in the 2

Gigahertz band of spectrum for the development of a new

wireless PCS subscriber service that will perform similarly

to cellular systems and will likely become the next

generation of competitors to cellular services. Service

providers have developed conceptual plans and in some cases

have demonstrated PCS systems. However, development and

implementation of such plans are at least two to five years

away from commercial service. PCS, therefore, is at an

immature stage of development that will allow the features

needed for electronic surveillance to be built as an

integral part of new systems.

PCS systems will operate at much higher radio frequencies (2

Gigahertz) than cellular systems (800 Megahertz). The higher

operating frequency reduces the distance that a subscriber

can be from a base radio station (cell) and maintain

communication. PCS systems, therefore, will consist of many

more smaller cells (microcells that cover a diameter of up

to one mile around the antenna) to cover an area than is now

commonly used by cellular service providers to serve the

same size area. Unlike current cellular systems, PCS systems

will be fully digital, and PCS handsets, will operate at

lower power levels.

The major difference between the features offered by

cellular services and PCS is the one-number service to be

offered by PCS. A single-number system allows maximum

personal mobility. Under this concept, a single directory

number would be used to direct all calls to a user wherever

he or she is. Cellular systems currently offer a measure of

personal mobility by forwarding calls to a user's cellular

telephone when they travel. But this feature operates

independently of the Public Switched Telephone Network

(PSTN) landline system and is only accessible through

cellular service providers with databases that track a

subscriber's location. Landline switching routines were

based on having a directory number associated with a fixed

location, not a mobile terminal.

The concept of one-number service (it has also been dubbed

Follow Me) would integrate the landline network into the

switching fabric of PCS by establishing a nongeographic

prefix--500 --in place of the area code. The 500 number

would indicate to the landline carrier that the call needs

special handling to route it to a PCS or cellular carrier.

(see footnote 18) To do this, the landline carrier's

Intelligent Network technology (infra) must be integrated

with the PCS and cellular system, all using common routing

databases. Should this level of integration be obtained, a

personal handset or a cellular terminal could be used either

as a mobile instrument, or a substitute for the cordless

residential telephone.

PCS is in an early stage of development. There is

considerable uncertainty as to what the standards will be

for the industry. Given PCS technology's stage of

development, accommodating the law enforcement agencies'

needs for electronic intercepts can follow a more logical

development and progression than is possible for either

cellular or landline networks that have an installed

technological base that must be adapted or modified to

comply with the requirements of the Act.

Configuration of a PCS System

The main components of a PCS network are similar to those of

a cellular network, although different names are assigned to

analogous parts of the system that perform the same function

in each. The PCS Switching Center (PSC) operates very much

like the Mobile Switching Center (MSC) in the cellular

system. Both serve as a gateway to connectivity with the

Public Switched Telephone Network (PSTN) and other external

networks. (See figure 2-7.)

The Terminal Equipment (TE), i.e., user equipment, such as a

computer or data terminal, can communicate with the PCS

infrastructure in either a wireless of wireline mode. The

Radio Personal Terminal (RPT), (a lightweight, pocket-size

portable radio terminal) directly accesses the Radio Port

(RP) for connecting the user to telecommunications services

while stationary or in motion. The TE may use either

Integrated Services Digital Network (ISDN) or non-ISDN

transmission protocols. Wireless access is through Radio

Terminations (RT), which terminates voice and data for the

TE and forwards the signal information in digital form to

downstream components, i.e., the PCS Switching Center (PSC)

for processing. Wireline access from a TE is linked directly

to the PSC.

The Radio Port Controller (RPC) coordinates the wireless

traffic received from the Radio Ports. It may also control

handoff of mobile-to-mobile, or mobile- to-fixed-location

calls placed among or between users through Radio Ports

under its control. The RPC coordinates all calls placed or

received by wireless users, and serves as the gateway to the

PCS Switching Center.

The Radio Access System Controller (RASC) coordinates the

functions among the Radio Port Controllers under its

control. It supports the exchange of call, service, and

handover control signaling and the transfer of terminal and

user information. The RASC may also perform the internal

bookkeeping function of charge recording, as well as linking

with Terminal Mobility Controllers (TMCs), and the Personal

Mobility Controllers (PMCs), which manage the terminal

registration, authentication, locating and user/terminal

alert functions stored in the Terminal Mobility Data Store

(TMD) and Personal Mobility Data Store (PMD), respectively.

The PCS Switching Center (PSC) performs the connection

control switching functions for accessing and

interconnecting outside network systems to provide end-to-

end services. Since PCS systems are designed to provide

services to users based on the user's personal identity,

rather than on a physical location as does wireline services

(and to some extent cellular services), the PSC must

interact with the PMC (and its supporting PMD) to access the

user's service profile for registration, authentication,

call alerts (ringing), and call management. The PCS must

also have access to the service limitations and restrictions

for a specific user, so therefore it may also have to

interact with the TMC for information about wireless

terminals.

A PSC serves five functions:

1. basic call and connection control for access and

interswitch routing,

2. service control for personal communications users

and terminals,

3. switch bearer connections to support handoff among

Radio Port Controllers,

4. mobility management associated with personal

communications users and terminals, and

5. network control and associated interworking for

access to external networks.

The Terminal Mobility Controller (TMC) and an associated

database (Terminal Mobility Data-Store, TMD), and the

Personal Mobility Controller (PMC) and an associated

Personal Mobility Data-Store (PMD), provides control logic

to the system elements. The TMC/TMD handles authentication,

location management, alerting, and routing to the

appropriate RPT/RTs. The PMC/PMD provides information for

personal user authentication, service request validation,

location management, alerting, user access to service

profile, privacy, access registration, and call management

(routing to destination).

Internal systems functions, e.g., systems monitoring,

testing, administering, and managing traffic and billing

information, is handled through Operations, Administration,

Maintenance, and Provisioning (OAM&P) components.

Internetworking Functions (IWF) serve to ensure that all

networking technologies work consistently and seamlessly to

provide PCS users reliable service.

The PCS system, like the cellular systems, will be able to

connect with a variety of outside networks that offer a

range of services, including wireline (local and

interexchange carriers), cellular, Competitive Access

Providers (CAPs), etc.

It is yet uncertain whether PCS will provide Auxiliary

Services. These include voice mail, paging, short-message

service, etc.

Configuration of PCS Intercept Approaches

If all calls to and from a PCS intercept target are

processed by the PCS Switch Center (PSC), with no calls to

or from the target being switched at the Radio Port

Controller (RPC) without first routing through the PSC, then

electronic surveillance for PCS systems is analogous to the

switch-based solutions being considered for cellular and

wireline services.

Registration and Activation--The Personal Mobility Data

Store (PMD) and the Personal Mobility Controller (PMC),

which store and control personal service information, can be

used to flag an intercept subject for surveillance. If a

home PCS service provider is requested by a law enforcement

agency to implement an intercept, the intercept subject's

PMD/PMCT entry would be modified to show:

o Intercept Subject Identifier (personal and/or terminal

number);

o Requesting Law Enforcement Agency;

o Monitor Site Location (line/directory numbers); and

o Authorization and Access Information. This information

would be sent to the home service provider's TMC/TMD and

noted as a temporary intercept request.

Upon receiving a request for services from the intercept

subject, the TMC/TMD would activate the intercept.

In the case that a nonhome PCS service provider that does

not have control over an intercept subjects PMD/PMC is

requested by a law enforcement agency to initiate an

intercept, the service provider would enter the subject's

personal service information and intercept information in

the its TMC/TMD. The TMC/TMD would activate an intercept

when a subject requests service (a PMC/PMD might also

activate intercepts under certain conditions).

Intercept Access Functions--A PCS intercept is activated

when the subject originates a call, receives a call, is

provided handover treatment, is disconnected from a call,

uses a vertical service (e.g., call forwarding, call

waiting, three-way calling), registers, or changes his or

her service profile information. The handling of vertical

service features is similar to the manner in which those

services would be handled through switch-based solutions and

cellular service.

When an intercept is activated, connection is made to the

authorized monitoring site for call content and control

information. Call setup information would be sent to the

monitoring site as it becomes available.

PCS Information Elements

PCS operations use about 70 different message types to

maintain communications and services. At least 14 of these

messages may be of use to law enforcement agencies. (See

table 2-2.)

Location information, when authorized to be provided to law

enforcement officials, is derived by correlating the Routing

Number Bearer Channel and Channel ID to the PCS system

component, e.g., Radio Port (RP), supporting the connection

to the mobile subscriber.

Advanced Intelligent Network (AIN)

AIN architecture distributes the service logic throughout

the network to support the many features and services

available to subscribers. Therefore, it may be more

difficult to identify calls that are associated with an

intercept subject or to determine the origin or destination

of calls to or from the subject. Additional functions will

have to be built into switch-based solutions to meet the

requirements of P.L. 103-414.

AIN is a system of interrelated computer-based components

linked to a switched or wireless telecommunications network

that provides a framework for services, e.g., call

forwarding, credit card authentication, personal

identification numbers, speed calling, voice dialing, etc.,

independent of the call process. AIN functions reside in

network elements, which can communicate among themselves and

with a controlling switch. In some cases, subscribers can

access and control the databases for AIN services (e.g.,

speed calling lists) without the intervention of a service

provider.

AIN (see footnote 19) architecture consists of signaling

systems, switches, computer processors, databases, and

transmission media, which provides customized software-

controlled services. (See figure 2-8.)

Deployment of AIN is not uniform throughout the Public

Switched Telephone Network (PSTN). It is being phased into

the national system through progressive upgrades in software

modules and intelligent network elements, which increase the

functionality and flexibility of AIN. (see footnote 20)

Since AIN permits peripheral intelligent elements (software-

controlled Intelligent Peripherals (IP)) to share control of

a call with switch-software control, AIN might present

special problems to intercepting the communications of

wiretap target subjects. (see footnote 21)

Signaling System Seven (SS7) switches and the national

network based on the SS7 standard enable broad deployment of

interactive AIN functions in the Public Switched Telephone

Network (PSTN). The SS7 network signaling and processing is

carried by an ISDN network. There are three major groups of

technologies in the AIN architecture (See figure 2-8.):

1. Network Elements (NE), Service Switching Points

(SSPs), non-SSP switches, and Signaling Transfer Points

(STPs);

2. Network Systems (NS), Service Control Points (SCPs),

Adjuncts and Intelligent Peripherals (IPS); and

3. Operations Systems (OSs), capabilities that provide

network and service operations as their primary functions

(Operations Systems may be unique to a service provider).

In general, AIN is not considered to be a part of the

switching system. A switching system may include AIN

capabilities, which generally consist of triggers in call

processing and feature software, that if set, transfers

functional control to another network platform. Many of the

intelligent functions are part of the Stored Program Control

Switches (SPCS), thus technical approaches for meeting law

enforcement's intercept needs at SPCS are switch-based

solutions (supra). However, some of the intelligent

peripherals (IP) and adjunct components contain interactive

software that allows subscribers to directly alter databases

that control services and features available to them. It may

therefore be necessary to query these peripheral components

directly (or via a SPC) to provide law enforcement agencies

the most current information available about an intercept

target. This will require special access features that are

not necessarily part of the switching process at the SPCS.

A Service Switching Point (SSP, See figure 2-8 above.), is a

special kind of switch (e.g., an end office switch or a

tandem switch) that contains AIN switch capabilities. A SSP

can identify calls associated with AIN services. When a call

is identified that requires AIN treatment, the SSP initiates

a dialog with a Service Control Point (SCP) or peripheral

where the information and software logic for the requested

service is located. A non-SSP switch is one that does not

have AIN capabilities, but is able to detect when a call

requires AIN processing and route them to a SSP for

processing.

Developing Technologies

The field of telecommunications is moving rapidly. A stream

of new technologies is queued to complement or compete with

the established communication systems of today. Some of

these technologies have been waiting in the wings for their

time to come as market demand and opportunities present

themselves. Others are of newer vintage, such as some of the

developing packet switching and satellite-based wireless

communication systems. The new technologies may--or likely

will--present new obstacles to law enforcement's needs for

electronic surveillance in the future.

Since the deployment of these new technologies is still in

the future, the range and magnitude of the problems that

they may present to law enforcement is a matter of speculation. A couple of th

e more prominent technologies

that are either in a preliminary stage of deployment or are

poised for commercial deployment are briefly described

below.

Satellite-Based Wireless Technologies

Satellite technology has been part of the communication

system since the middle 1960s. Satellite communication is an

integral part of the international telephone network. (see

footnote 22) Today, when high-speed optical fiber capable of

carrying immense volumes of communication to Europe or the

Far East fail, satellite communication links stand ready to

carry the redirected traffic.

Most of the early satellite systems were matched to the

commercial need of wholesale communications, i.e., from one

service carrier's switch to another carrier's switch, hence

to wirelines. New satellite systems on the drawing board or

in early phases of implementation will link directly with

the user. Some propose to operate much like cellular or PCS

systems, linking the user and his or her handset directly to

the space-based satellite system.

Two classes of satellite-based communication services are

being considered: GEOS--Geosynchronous Earth Orbiting

Satellites; and LEOS--Low Earth Orbiting Satellites.

Geosynchronous Earth Orbiting Satellites (GEOS)

GEOS systems will be placed in a geosynchronous orbit at the

prescribed distance of 22,300 miles above the equator. These

satellite systems will use a higher transmitting power level

than will the LEOS (because of the difference in distance to

the earth). GEOS can be deployed either in a constellation

(several satellites), or as a single satellite, depending on

the nature of the service that they will deliver.

Deployment of a constellation of GEOS in several different

orbit locations can provide global communication. The system

satellites would be linked by inter- satellite

communications to manage the switching and administration.

Interconnection with the Public Switched Telephone Network

(PSTN) can be provided, and subscribers can manage their own

communications through personal ground stations.

A single GEOS satellite can be equipped to aim spot beams to

achieve regional communication coverage. Such systems

operate much like a cellular system (each beam representing

a space-deployed cell site), with switching systems

analogous to the Mobile Cellular Switches (MCSs) of a ground

based cellular system.

The technical impacts of these technologies on law

enforcement agencies' ability to conduct authorized wiretaps

will come from two sources:

1. Caller-to-caller direct links through a satellite

switch that bypasses the terrestrial switched system; and

2. Jurisdictional problems of conducting authorized

wiretaps across the boundaries of sovereign nations.

Low Earth Orbiting Satellites (LEOS)

LEOS are placed in lower orbital positions (500 to 1,400

kilometers [310 to 870 miles]) than are Geosynchronous Earth

Orbital Satellites (GEOS). The lower orbital paths allow

them to be operated with less power and reduce the time

delays that plague communications (time delays limit the

usefulness of GEOS communications for some time-sensitive

applications) using GEOS, which orbit at distance up to 60

times greater than LEOS. LEOS systems will be less costly to

build and deploy than GEOS.

There are two classes of LEOS: Little LEOS--those using many

small satellites (36 or more for global communications); and

Big LEOS. (see footnote 23) (See figure 2-9).

The Federal Communication Commission (FCC) created the

distinction between Big and Little LEOS based on the

allocation of frequencies to be used (Little LEOS below one

Gigahertz; Big LEOS above one Gigahertz), and services they

are authorized to provide. Little LEOS handle data traffic

only, e.g., messaging, tracking, and monitoring; Big LEOS

can provide global mobile telephone service (similar to

cellular and PCS) as well as data services, facsimile,

paging, geographic positioning, and other services tailored

to users needs.

Little LEOS--The services offered by Little LEOS will

primarily operate in nonreal time, i.e., store and forward

messaging and data. Little LEOS services are scheduled for

deployment and operation between 1996 and 2000. The service

providers consider emergency and personal communications,

law enforcement (vehicle location), environmental

monitoring, utility monitoring (power grids), shipping cargo

management, etc. as potential markets.

Each Little LEOS system will consist of between 25 and 50

satellites orbiting at about (621 miles) above the earth.

One or more earth stations will serve as a gateway to the

space-deployed system. The earth stations may be linked to

other peripheral message management nodes, which could be

linked to conventional wireline or wireless communications

networks.

Some regulatory matters, domestic and foreign, are yet to be

resolved.

Big LEOS--Big LEOS systems are in the development stage, and

have not yet been assigned international frequency

allocations, although the FCC has recently granted licenses

to three of the five potential service providers.

Big LEOS can provide a wide range of voice and data

services, including all of the services provided by Little

LEOS, plus cellular- or PCS- like telephone service.

Communications can be from mobile or fixed Earth stations.

These satellite-linked services are considered to be

possible alternatives to expensive land-based wire systems

in the remote areas of developing countries. The cost,

however, will be high, and international country-by-country

regulatory questions may slow global deployment.

Big LEOs, operating at frequencies above one Gigahertz, will

orbit at distances of (310 to 870 miles) above the earth.

Communications from a mobile handset would first seek a

transmission path to a local terrestrial cellular (or PCS)

network (if one exists) for connection to a wireline

network. In areas beyond the reach of a cellular network, a

direct connection to a satellite station would be made,

which would relay the call back to earth for connection with

a remote wireline network. After cut-through to the wireline

network, a call would be switched as would any other call

originating from a cellular, PCS, or conventional switched

system.

However, Motorola's proposed Iridium system (see footnote

24) would permit callers to make a direct connection from

one handset to another through intrasatellite links.

Satellite-to-satellite communication could seriously

complicate law enforcement's ability to perform lawful

electronic intercepts.

Packet Switched Transmission Technologies

The historical evolution of telephone technology was aimed

at optimizing voice communication. Appeals from the

fledgling computer users of the 1960s to the telephone

companies for better methods of transmitting data from one

computer to another were largely ignored. This led the

government and the computer industry to seek other means for

filling its needs. Thus, two technological cultures

developed independently of each other, with little in common

between the two and with little interaction among scientists

and engineers in both camps. (see footnote 25)

Today, computers are the telephone network, and the fastest

growing traffic on telephones networks is data and computer-

mediated communications. The lingua franca of both telephony

and computer communications is the digital transmission

mode. Voice, data, video, and images are all transmitted,

and for practical purposes, look and are processed the same

way. The concept of a National Information Infrastructure

(NII) is based on the common ground provided by digital

technology that can serve the needs of all users.

While the telephone industry continued to improve the

efficiency, quality, and reliability of circuit-connected

architecture for voice traffic (which tends to ebb and

flow), the computer communication industry developed packet

technologies to handle the bursty (short transactions with

periods of no traffic) nature of high-speed computer data.

A number of packet-switched networks were deployed to meet

the increasing need for computer communication. Many of

these networks were part of a national computer network

inspired by the Department of Defense (DOD) in the late

1960s to meet its mission needs. (see footnote 26) DOD was

instrumental in developing packet network technology and

packet protocols (the rules for formatting, addressing, and

routing the packets within the network). The DOD protocols

and routing technology (Transmission Control

Protocol/Internet Protocol--TCP/IP) has become a defacto

industry standard, and the operating standard for the

Internet. The Internet's phenomenal growth and success

spawned the vision of a National Information Infrastructure

(NII), which appears poised to subsume all

telecommunications under its aegis.

Prior to the development and deployment of packet-switched

networks, computer users relied on modems

(modulate/demodulate) for communication over the telephone

network. Modems convert the digital signals produced by a

computer to electrical signals (analog signals) that look

and behave in the telephone network as though they were

sounds or spoken words. At the receiving modem, the analog

electrical signals are converted back to digital form before

re- entering the receiving computer. Modem technology is

still a common means for communicating between computers

over the Public Switched Telephone Network (PSTN). However,

the speed of modem transmission is relatively slow and thus

limits their usefulness for high-speed, broadband

applications, e.g., video and images.

A packet-switched network can send information over several

different routes (like choosing alternative interconnected

highways) to reach a destination. Data placed in packets

(segments of data and routing information) containing

special control information (source and destination address)

are sent along any route within the network that happens to

be available that leads to the addressee. (see footnote 27)

Because of the random nature of the route to the destination

taken by packets, they arrive at different times and out of

order, although each contains only a portion of the data or

message sent by the originating computer. Packets must be

assembled and disassembled at the receiving end and put in

the same order or sequence as they were sent.

Intervening years have brought increased demand for switched

broadband networks to handle the high capacities needed for

video, images, and data. In response to this the telephone

industry has attempted to recoup the business it lost to

private networks and information service providers by

improving its computer communication services.

In 1976, the telephone industry adopted an international

packet switching standard designated X.25, a relatively slow

transmission service. (see footnote 28) Since then,

Switched Multimegabit Data Service (SMDS) and Frame Relay (a

technology that uses packets of variable payload length)

(see footnote 29) have been introduced. Both SMDS and Frame

Relay are precursors of what the telephone industry

considers to be its technology backbone of the future--the

Asynchronous Transfer Mode (ATM)

Asynchronous Transfer Mode (ATM)

ATM is a fast packet switching technology, i.e., it provides

fast processing power that can keep up with the increased

bandwidth (volume) available with very fast transmission

systems over optical fiber, which are required for video.

ATM is flexible enough to support voice, video, images, and

data. It is a scaleable technology, i.e., it can be used to

link a few computers in an office setting, it can serve a

campus setting, like Capitol Hill, it can be expanded to

cover an area the size of Washington, DC., or it can work in

a national network, as proposed for the National Information

Infrastructure. It has the added advantage of being accepted

and supported by both the computer industry and the

telecommunications industry.

ATM has two distinguishing features:

1. It is cell-based. Instead of variable-length frames,

as used by Frame Relay and other packet networks (sometimes

several thousand bytes, which contain 8 bits of binary

information), ATM uses fixed-length cells. (See figure 2-

10.)

2. ATM is connection-oriented, i.e., every cell in the

ATM transmission travels over the same route. The network

path, or virtual circuit, is designated during call setup by

information contained in the cell header. The header in the

ATM cell contains the information a network needs to relay

the cell from one network node (switching point) to the next

over the pre- established route.

ATM connections are sets of routing tables retained in an

ATM switch, which are matched with the address contained in

an ATM cell header. ATM addresses, unlike a geographically

locatable Directory Number (DN) or a TCP/IP packet, only

have meaning for locating one point (node) in an ATM net to

the next node.

Each ATM switch is provided with a set of lookup tables

(computer database), which identify an incoming cell by

header address, route it through the switch to the proper

output port, and overwrite the incoming address with a new

one that the next switch along the route will match with an

entry in its routing table. Thus, the message is passed

along from switch to switch, over a prescribed route, but

the route is virtual, since the switch carrying the message

is dedicated to it only while the cell is passing through

it.

The address in the header of an ATM cell contains two

fields:

1. Virtual Path Identifier (VPI); and

2. Virtual Channel Identifier (VCI).

The two-part addressing scheme allows the network to

designate major trunks between locations, and identify the

individual circuits (channels) within the trunk. A virtual

path may consist of several virtual channels. Thus, the VPI

might represent a trunk between two cities. The VCIs might

represent individual calls. Switching equipment along the

network can route all the calls on the basis of just the VPI

without having to query the rest of the address (VCI) until

the trunk gets to the final location, where the individual

calls are distributed to their destinations. (See figure 2-

11.)

Implications for Electronic Surveillance--If ATM becomes the

enabling technology for the nation's next generation of

multimedia networks (the NII) as some foresee, interception

of electronic communication will become more difficult.

Packet networks will require a substantially different

approach to surveillance than used for today's digital

telephony. Since the address is an integral part of the

packet that contains the message data as well, it will be

necessary to develop means to insert hooks into the packet

header to identify the sender and the intended recipient.

Packets in connectionless services, e.g., Internet (TCP/IP),

and Frame Relay, have destination addresses embedded in the

packet that are identifiable with a physical location and/or

an individual. A packet may travel any number of alternate

routes in reaching its destination. Since information is

segmented into variable length packets, connectionless

routing can result in a packet containing part of the

message that is sent before another, may reach its

destination after the second or later packets that are sent.

Connectionless packets must be reassembled in proper order

to make sense of the message. Once a message is sent by an

intercept subject, random routing will complicate the

process of identifying the packets--and only the packets--

that are authorized to be lawfully intercepted until they

reach their destination.

ATM establishes a virtual circuit between ATM switches (but

not physical connections as used in the Public Switched

Telephone Network) that routes each ATM cell over the same

trunk and channel. Many different calls (video, voice,

images, data) in addition to that of the intercept subject

or his or her correspondent may be moving over the same

routes simultaneously and/or intermittently. The route in

the header address is overwritten with a new address at each

ATM switch, which is translated from the switch route lookup

table. The unique routing protocol of ATM will require new

approaches to message identification and verifications and

will complicate trap and trace and pen register procedures.

Internet (TCP/IP) and Frame Relay packets can be sent over

ATM networks, although ATM cannot recognize the embedded

packet addresses in the headers. ATM incorporates the entire

TCP/IP or Frame Relay packet into an ATM cell and

readdresses the cell according to the ATM routing protocol.

At the point of termination, the ATM envelope is stripped

away and the TCP/IP packets are assembled for processing by

the recipient. This may further complicate the

identification and association of a call from or to the

subject of a lawful electronic intercept. Moreover, there is

currently a market in redirecting TCP/IP traffic, or

changing a sender's address to an anonymous address. Some of

these services are based in foreign jurisdictions, thus

possibly complicating the legal procedure for identifying

communications from or destined for a lawful intercept

subject.

In addition to the technical difficulty in dealing with

packet-based communication in general, and ATM networks in

particular, the legal requirements for establishing a lawful

electronic intercept may be more difficult. The isolation of

an intercept subject's outgoing and incoming traffic

according to the strict requirements that assure the privacy

of other communicants may be more difficult. Minimization,

i.e., screening or filtering nongermane information from the

intercepted communication, also may be more complicated.

*

CHAPTER 2 FOOTNOTES

*

1 Material in this chapter was synthesized from documents

prepared by the various action teams of the Electronic

Communication Service Providers (ECSP) committee, operating

under the aegis of the Alliance for Telecommunications

Industry Solutions (ASIS). The OTA project director for this

report attended the functions of the ECSP under a

nondisclosure agreement. The material herein contains no

information considered to be sensitive by the law

enforcement agencies, or proprietary by the industry

personnel reviewing the draft document.

2 Testimony of A. Richard Metzger, Jr., Deputy Chief, Common

Carrier Bureau, Federal Communications Commission, before

the U.S. House of Representatives, Committee on Energy and

Commerce, Subcommittee on Telecommunications and Finance,

Sept. 13, 1994, 103d Cong., 2d sess.

3 Federal Communications Commission, Fiber Deployment

Update, table 1, May 1994.

4 Id at table 5.

5 Testimony of Thomas W. Wheeler, President and CEO,

Cellular Telecommunications Industry Association, before

hearings of the U.S. House of Representatives, Committee on

Energy and Commerce, Subcommittee on Telecommunications and

Finance, Sept. 19, 1994.

6 Cellular Telecommunications Industry Association, "The

Wireless Factbook," p. 36, spring 1994.

7 James Carlini, Telecom Services, "Utilities are Hungary

for a Piece of the Action," Network World, p. 55, Sept. 19,

1994.

8 Testimony of Hazel E. Edwards, Director, Information

Resources Management/General Government Issues, Accounting

and Information Management Division, U.S. General Accounting

Office, before a joint hearing of Subcommittee on Technology and the Law, U.S.

Senate, and the Subcommittee on Civil and

Constitutional Rights, Committee on the Judiciary, U.S.

House of Representatives, Aug. 11, 1994, p. 5.

9 The term "roaming" generally applies when the subscriber

initiates or receives a call in other than his or her home

area.

10Roaming within the service area of another service

provider is contingent on the home cellular provider having

entered a "roaming agreement" with the second carrier.

Roaming privileges are not uniform and reciprocal among all

providers.

11 Some rural cellular companies' may not own a MSC switch,

but instead may lease the use of an adjacent cellular

companies switch. In this case the leasor service provider

would have control of the switch, and any intercepting

activities would have to be performed by the leasor although

an authorized wiretap may be served on the leasee. This

problem may need to be addressed by promulgating

regulations.

12 "Handoff" occurs when a subscriber travels from one

service area to another while a wireless call is in

progress.

13 Maintenance ports built into the current generation of

cellular switches allow access to information needed by law

enforcement agencies. However, the number of access ports

are limited, and information at these ports can only be

recovered by manual queries. This limits their usefulness

for dealing with handoffs from MSC to MSC, slows the

recovery of information, and requires the involvement of

several law enforcement officials to implement some cellular

intercepts.

14 Each cellular service provider within a market area is

assigned 416 channels for communication. Twenty-one of the

channels are control channels that continuously connect each

activated handset with the cellular system.

15 Short Message Service is a function offered by some

cellular service provider. It is similar to paging, with

abbreviated messages being transmitted over the control

channels.

16 The basic authority for instituting a pen register

surveillance is contained in 18 USC 3123. More latitude is

granted for pen registers to obtain more detailed

information on a subject is authorized under the procedures

set forth in 18 USC 2703.

17 This process is still under consideration by industry and

law enforcement agencies.

18 Landline carriers now use a "500" dialing sequence to

allow subscribers to use a touch-tone phone to update a

database that indicates where incoming calls should be

routed for cellular service. These functions are not

integrated into the landline service provider's switching

system, however.

19 AIN architecture has been primarily developed by Bellcore

in collaboration with its clients, the Bell Regional

Operating Companies (RBOCs). The interexchange carriers

(AT&T, MCI, Sprint, etc.) have similar Intelligent Network

(IN) systems in their networks. AIN can also be deployed in

Cellular and Personal Communication Services (PCS).

20 Beginning in 1983, intelligent elements have been

progressively introduced into the Public Switched Telephone

Network (PSTN). In the 1980s, Phase 1 of Bellcore's IN

architecture (IN/1) was introduced. This was followed by AIN

Release 0, AIN 0.1,. . .AIN 0.X. The introduction of AIN

Release 0 in 1991 marked the transition from providing

telephone service totally under switch- control software to

providing services through shared control among intelligent

network elements.

21 For instance, Service Creation Environments (SCEs) allow

nonprogrammer users to create a new service using icons

representing functional service blocks without the

intervention of the service provider. Service Management

Systems (SMSs) allow users direct access to their services

so they can make real-time adjustments as their requirements

change.

22 Satellites are used extensively for video, data

communication, and for communication with ships at sea. For

the purpose of this discussion, the use of satellite based

systems for personal wireless applications to the end user

will be the focus.

23 The terms "big" and "little" have little to do with the

physical size of the satellites. The primary difference is

the radio frequencies that have been allocated to each

service. "Little" LEOS will operate at frequencies less than

one Gigahertz; "Big" LEOS will operate at frequencies above

one Gigahertz. The difference in frequencies affects the

nature of the services offered by each of the two LEOS.

24 Motorola's Iridium system would use 66 LEOS orbiting in

11 different planes of 6 satellites each. This would provide

worldwide telephone and data communication linked to 15 to

20 Earth stations connected to terrestrial wireline

networks. Satellite-to-satellite cross links would be

capable of data rates up to 25 Million bits/second (Mbps).

Several other companies are proposing similar systems, e.g.

Globalstar (Loral and Qualcomm, Inc.), Odyssey (TRW, Inc.

and Teleglobe), Ellipso (Mobile Communications Holding,

Inc.), ECCO (Equitorial Constellation Communications--

Constellation Communications, Inc., Bell Atlantic

Enterprises International, and Telecommuniccacoes

Brasileiras S.A.). Not all of these systems will offer

intra-satellite communications from caller to caller as will

Iridium.

25 Even today the schism between the two industries remains

evident. The two cultures continue to exist, with different

language and different perspectives on communications,

although both use common digital technology and are being

forced to act as one, if ever so reluctantly.

26 A number of regional networks and Internet service

providers have appeared to meet the increasing demand. Many

of these entities lease lines from the Public Switched

Telephone Network (PSTN), although the Internet operates

independently of the PSTN.

27 Packets have been compared to envelopes used for

traditional mail. The data or information in the packet data

field is like the writing on paper, and the numerical

address of the computer to which it is sent that is

contained in the packet header is like the address on an

envelope.

28 X.25 packet switching carries a relatively low data rate

of approximately 9.6 kilobits/second.

29 Frame Relay is not based on fixed-length data frames, it

uses flags in the header and trailer to indicate the

beginning and end of frames.

APPENDIX A:

*

ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

*

APPENDIX A:

SECTION-BY-SECTION SUMMARY OF THE COMMUNICATIONS ASSISTANCE

FOR LAW ENFORCEMENT ACT PUBLIC LAW 103-414

SERVICES COVERED

All "telecommunications carriers" that are considered to be

common carriers, including mobile service, e.g., local

exchange carriers, competitive access providers (CAPs),

interexchange carriers, cellular carriers, providers of

personal communications services (PCS), satellite-based

service providers and other service providers that may act

as a replacement for a local telephone exchange as

determined by the Federal Communications Commission (FCC),

e.g., cable television operators, and electric and other

utilities that provide telecommunications for hire to the

public. (Sec. 102(8))

SERVICES EXCLUDED

Service providers engaged in "information services," e.g.,

electronic messaging services (electronic mail, electronic

form transfer, electronic document interchange (EDI)),

information and databanks available for downloading by a

subscriber, private networks, and Internet service

providers, (Sec. 102(6)), and other services that the

Attorney General (AG) and the FCC may exclude from coverage.

(Sec. 102©)

CARRIER CAPABILITIES REQUIRED

Operational Requirements

Upon a lawful request by a law enforcement agency, a

telecommunications carrier must provide the agency the

capability to selectively isolate and intercept electronic

traffic and call identification information in an

understandable format, to be delivered beyond the carriers

premises. This must be capable of being done instantaneously

in real time or recorded or stored for latter access.

Interception of calls either originated or received by a

subscriber must be able to be identified in a manner that

will satisfy the rules of evidence before a court of law.

(Sec. 103(a))

Constraints

If the information is gathered only under the authority for

"pen registers and trap and trace devices," (unless a court

authorizes otherwise) call identification information must

not reveal the physical location of a subscriber other than

that could be determined from a telephone number. (Sec.

102(a)(2)) The information must be acquired without

disrupting other communications, while preserving the

privacy of other subscribers not under surveillance. The

confidentiality of the government's surveillance must also

be protected.

Limitations--Law enforcement agencies can neither require

the carriers to adhere to any specific technologies to

achieve the objectives of the Act, nor prohibit the adoption

of any specific technologies. (Sec. 103(b)(1)) Carriers are

not responsible for decrypting any encrypted messages that

are not encrypted as a service by the carrier. (Sec.

103(b)(3))

Special Provisions for Mobile Service--A carrier must be

able to notify a law enforcement agency before, during, or

immediately after the transfer of control of the

communication to another carrier when communication is

handed off, redirected, or assigned to another carrier in a

different service area. (Sec. 103 (d))

CAPACITY AND PERFORMANCE REQUIREMENTS

Capacity

Initial (Actual) Capacity--Within one year the Attorney

General must notify the industry of the number of

simultaneous communication interceptions, pen registers, and

trap and trace devices that the law enforcement agencies'

may conduct and use within the four-year period following

approval of the Act.

Maximum Capacity--The Attorney General must also provide

similar information for the period beyond the initial four-

year period following approval of the Act. (Sec. 104(a)) The

information provided by the Attorney General may be based on

the type of equipment, type of service, number of

subscribers, type or size of carrier, nature of service

area, and should be given in terms that are specific for

geographic areas.

Performance

Initial (Actual) Capacity--Within four years after approval,

or three years after notification of needed capacity by the

Attorney General, should the Attorney General's notification

occur later than the one year deadline set by the Act, the

carriers must accommodate the law enforcement agencies needs

simultaneously, and have the capability to expand to the

maximum capacity needed as determined by the Attorney

General. (Sec. 104(b)(1))

Maximum Capacity--At the expiration of the period that

carriers are required to meet the needs of initial capacity,

the carriers are required to ensure the capability to

increase the number of interceptions as needed by the law

enforcement agencies, up to the maximum capacity set forth.

(Sec. 104(b)(2))

Increases in Maximum Capacity--The Attorney General will

periodically review the needs of the law enforcement

agencies and notify the industry of any needed changes in

capacity. (Sec. 104©(1))

Compliance with Changes in Maximum Capacity--Within three

years after the Attorney General notifies the carriers of

the need to increase the maximum capacity, a carrier must

inform the Attorney General of any systems or services that

do not have the capacity to simultaneously meet the expanded

need of the law enforcement agencies. (Sec. 104©(2))

MEETING THE INDUSTRY'S OBLIGATIONS

Equipment Manufacturers

Carriers, manufacturers, and vendors are directed to

collaborate in developing and modifying technology and

equipment to meet the needs of law enforcement agencies.

(Sec. 106)

Government Responsibilities

The Attorney General, as representative of the law

enforcement community, must consult with industry

associations, standards-setting organizations,

telecommunication users, and state regulatory commissions to

facilitate the implementation of the Act. (Sec. 107(a)(1))

Standards

The Act relies on the integrity of the standards setting

process to meet the capability requirements set forth by the

Attorney General. If a carrier or manufacturer adopts an

accepted technical requirement or standard, it will be

considered to meet the capabilities requirements. (Sec.

107(a)(2)) The absence of technical requirements or

standards, however, does not relieve a carrier or

manufacturer from an obligation to satisfy the capability

requirements. (Sec. 107(a)(3))

ROLE OF THE FEDERAL COMMUNICATION COMMISSION

Failure of Industry to Set Standards

In the absence of voluntary adoption of standards by

industry standards- setting organizations, or if the adopted

standard is believed to be deficient, an agency or

individual may petition the Federal Communication Commission

to establish technical requirements or standards. (Sec.

107(b))

Extending Time for Compliance

A carrier may petition the Federal Communication Commission

for an extension of the compliance deadline if meeting the

capability requirements is not reasonably achievable by that

time. The Commission may grant an extension of up to two

years. (Sec. 107©)

The Act authorizes the Federal Communication Commission to

adjust rates and rules for interstate and foreign

communication carriers within its jurisdiction to offset the

reasonable costs of compliance. (Sec. 229(e))

ENFORCEMENT

Court Order

A court may issue an enforcement order for specific

performance by a carrier if workable alternative

technologies or the capabilities of another carrier can not

meet law enforcement's needs, if technology is available to

reasonably achieve timely compliance. (Sec. 106(a))

Limitations if Technology is not Reasonably Achievable

A court may not issue an enforcement order in excess of the

capacity for which the Attorney General has agreed to

reimburse the carrier (Sec. 106©(1)), or if the Federal

Communication Commission determines that compliance is not

reasonably achievable (Sec. 106©(2)), unless the Attorney

General has agreed to pay the costs for developing the

technology necessary to make compliance reasonably

achievable. (Sec. 109(a)(2)(A))

Prior Installed Technology

A court may not issue a compliance order for modifying

equipment installed before January 1, 1995, unless the

Attorney General has agreed to reimburse the carrier to

bring its facility into compliance, or the previously

installed equipment or service has been replaced,

significantly upgraded, or modified since that date. (Sec.

107©(3))

REIMBURSEMENT FOR COST

Installations Prior To January 1, 1995

Authorization to Reimburse--The Attorney General is

Authorized to pay the direct cost of modification of

equipment, facilities, or services deployed on or before

January 1, 1995, to establish the capabilities identified by

the Attorney General, if the Congress appropriates money for

such purpose. (Sec. 109(a)

Authorization of Appropriations for Reimbursement--A total

of $500 million is authorized to be appropriated over the

four fiscal years 1995 through 1998. (Sec. 110)

Cost Determination--The Attorney General is to establish

regulations to permit carriers to recover direct costs for

providing the capabilities and capacities through

modification of equipment, facilities, or services deployed

before January 1, 1995, including the cost of training

personnel, and the direct costs of deploying or installing

such capabilities needed to meet the requirements of law

enforcement. (Sec. 109(e)(2)(B))

Consequence of Attorney General Failing to Make Payment--If

a carrier requests payment to modify equipment, facilities,

or services deployed before January 1, 1995, and the

Attorney General has not agreed to reimburse the carrier,

the carrier is considered in compliance with the Act until

such equipment is replaced or significantly upgraded, or

otherwise undergoes major modification. (Sec. 109(d))

Installations After January 1, 1995

A carrier may petition the Federal Communication Commission

to determine whether compliance with capability requirements

is reasonably achievable with equipment, facilities, or

services deployed after January 1, 1995. The Commission must

make a determination within a year, having considered

whether compliance would impose "significant difficulty or

expense" on the carriers or users. (Sec. 109(b)(1))

Compensation

Compensation--If compliance is not reasonably achievable,

the Attorney General may agree to pay the carrier for

reasonable costs for making compliance requirements

reasonably achievable. If the Attorney General does not

agree to pay such costs, the carrier is deemed to be in

compliance. (Sec. 109(b)(2))

Appendix B: Electronic Surveillance Requirements Keyed to P.L. 103-414

*

ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

*

APPENDIX B:

ELECTRONIC SURVEILLANCE REQUIREMENTS KEYED TO P.L. 103-414

REQUIREMENT 1

A) Law enforcement agencies require access to the

electronic communications transmitted, or caused to be

transmitted, to and from the number, terminal equipment, or

other identifier associated with the intercept subject

throughout the service areas operated by the service

provider served with a lawful authorization. Law enforcement

agencies also require access to generated call-identifying

information necessary to determine the calling and called

parties. Law enforcement agencies will coordinate delivery

of these communications with the service provider in

accordance with Requirement 3(A) infra for each service

area. (Sec. 103(a)(1), Sec. 103(a)(2))

B) Law enforcement agencies require real-time, full-

time monitoring capability for interceptions. (Sec.

103(a)(1))

C) Law enforcement agencies require telecommunications

carriers to make provisions for implementing a number of

simultaneous interceptions. (Sec. 103(a)(1))

D) Law enforcement agencies require telecommunications

carriers to expeditiously provide access to the

communications of the intercept subject. (Sec. 103(a)(1))

REQUIREMENT 2

Law enforcement agencies require:

1) information from the telecommunications carrier to

verify the association of the intercepted communications

with the intercept subject, and

2) information on the services and features subscribed

to by the intercept subject prior to and during the

intercept implementation. (Sec. 103(a)(2))

REQUIREMENT 3

A) Law enforcement agencies require telecommunications

carriers to transmit intercepted communications to a

monitoring facility designated by the law enforcement

agency. (Sec. 103(a)(3))

B) During the intercept period, law enforcement

agencies require that the reliability of the services

supporting the interception at least equals the reliability

of the communications services provided to the intercept

subject. (Sec. 103(a)(3))

C) Law enforcement agencies require that the quality of

service of the intercepted transmissions forwarded to the

monitoring facility comply with the performance standards of

the telecommunications carriers. (Sec. 103(a)(3)

REQUIREMENT 4

Law enforcement agencies require the intercept to be

transparent to all parties except the investigative agency

or agencies requesting the intercept and specific

individuals involved in implementing the intercept

capability. Law enforcement agencies require the

implementation of safeguards to restrict access to intercept

information. (Sec. 103(a)(4))

Appendix C: Related OTA Reports for Further Reading

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ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

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APPENDIX C:

RELATED OTA REPORTS FOR FURTHER READING

o U.S. Congress, Office of Technology Assessment, Critical

Connections: Communication for the Future, OTA-CIT-408

(Washington, DC: U.S. Government Printing Office, January

1990)

o U.S. Congress, Office of Technology Assessment, The 1992

World Administrative Radio Conference: Technology and Public

Policy, OTA-TCT-549 (Washington, DC: U.S. Government

Printing Office, May 1993)

o U.S. Congress, Office of Technology Assessment, Advanced

Network Technology, OTA-BP-TCT-101 (Washington, DC: U.S.

Government Printing Office, June 1993)

o U.S. Congress, Office of Technology Assessment,

Protecting Privacy in Computerized Medical Information, OTA-

TCT-576 (Washington, DC: U.S. Government Printing Office,

September 1993)

o U.S. Congress, Office of Technology Assessment,

Information Security and Privacy in Network Environments,

OTA-TCT-606 (Washington, DC: U.S. Government Printing

Office, September 1994)

o U.S. Congress, Office of Technology Assessment, Wireless

Technology and the National Information Infrastructure, (to

be released Summer 1995)

Glossary

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ELECTRONIC SURVEILLANCE IN A DIGITAL AGE

*

Glossary

Access The technical capability to interface with a

communications facility, such as a communications line or

switch, so that law enforcement can monitor and receive call

setup information and call content.

Actual Capacity That portion of the Maximum Capacity

simultaneously required to conduct electronic surveillances

at or before a specified date in a given switch as indicated

by the Attorney General for all government agencies

authorized to do surveillance.

Advanced Intelligent Network (AIN) A system of interrelated

computer-based components linked to a switched or wireless

telecommunications network that provides a framework for

services, e.g., call forwarding, credit card authentication,

personal identification numbers, speed dialing, voice

dialing, etc.

Base Station The common name for all of the radio equipment

located at a single site for serving one or several cells.

Call Any wire or electronic signaling information generated

by a human or a computer acting as an agent for a human to

set up a physical or virtual connection to transit

information to another or multiple users (humans and/or

computer processes).

Call Content The same as "contents" as defined in 18 U.S.C.

2510 (8) and with respect to any electronic communication,

includes any information concerning the substance, purport,

or meaning of that communication.

Call Content Channel (CCC) The link between the surveillance

switch and the law enforcement agency that carries the call

content. The CCC may be a switched connection or a dedicated

path through the Public Switched Telephone Network (PSTN),

e.g., on a private line.

Call Data Channel (CDC) The interface between the

surveillance switch and the law enforcement agency that

carries the call set-up data. The CDC may be a switched

connection or dedicated path through the Public Switched

Telephone Network (PSTN) or may be separate from the PSTN,

e.g., via a private line or a packet switched network.

Call Setup Data Includes all of the setup and call release

information received and interpreted by the surveillance

switch as a regular part of processing the call as defined

in applicable standards and specifications for the services

being provided. For example, this includes the initial

digits dialed to access an Interexchange Carrier (IC) but

may not include those dialed via Dual Tone Multi-Frequency

(DTMF) after connection with the IC.

Call Setup Information When used with respect to any

electronic communication, the information generated during

the establishment of communications or transmission of a

protocol data unit such as a datagram, that identifies the

origin and destination of the call. For voice

communications, this information is typically the electronic

pulses, audio tones, or signaling messages that identify the

numbers dialed or otherwise transmitted, or caused to be

transmitted, by the intercept subject. It also includes

incoming pulses, tones, or messages that identify the number

of the originating instrument, device, or user. For data

services, this information is typically the source (calling)

address and destination (called) address contained in fields

of the data unit, such as in the header of a frame or

packet.

Calling Features Indicator The authorization and activity

status of the Mobile Switch features, including call

forwarding (unconditional, busy, no answer), call waiting,

three-way calling, and call delivery.

CDMA Code-Division Multiple Access.

Central Office In telephone operations, the facility housing

the switching system and related equipment that provides

telephone services for customers in the immediate

geographical area.

DTMF Dual tone, multi-frequency, i.e., push button dialing.

Electronic Communications The same as defined in 18 U.S.C.

2510 (12), any transfer of signs, signals, writing, images,

sounds, data, or intelligence of any nature transmitted in

whole or in part by a wire, radio, electromagnetic photo-

electric, or photo- optical system, etc. The term includes

"wireless communication," as defined in 18 U.S.C 2510 (1).

Electronic Serial Number A coded serial number assigned by

the manufacturer to the mobile unit.

Electronic Surveillance The statutory-based process and the

associated technical capability and activities of law

enforcement agencies related to the interception and

monitoring of electronic communications.

Handoff Occurs when a subscriber travels from one service

area to another while a wireless call is in progress.

Home Location Register (HLR) The location register to which

a user identity is assigned for record purposes, such as

subscriber information (e.g., Electronic Serial Number,

Directory Number, Profile Information, Current Location,

Validation Period). The HLR may or may not be located

within, and be indistinguishable from, a Mobile Switching

Center (MSC). A HLR may serve more than one MSC and the HLR

may be distributed over more than one physical entity.

Home Service Area The service area in which a customer has

subscribed to receive service.

Intercept Subject Person or persons identified in the lawful

authorization and whose incoming and outgoing communications

are to be intercepted and monitored.

Interface A shared boundary or point common to two or more

similar or dissimilar command and control systems,

subsystems, or other entities against which, or at which, or

across which useful information takes place.

Local Exchange An exchange where subscribers' lines are

terminated.

Local Switch A switch that connects one customer's line to

another customer's line, or to a facility that goes to

another switching system, i.e., a trunk.

Maximum Capacity That switch capacity (in terms of the

number of simultaneous surveillances and the number of

simultaneous monitorings) that cannot be exceeded in a

switch without revision of its generic software.

Mobile Identification Number An identification number

assigned by the service provider to a subscriber.

Mobile Station (MS) The interface equipment used to

terminate the radio path at the user. It provides the user

the ability to access network services.

Mobile Switching Center (MSC) An automatic switching system

that constitutes the interface for user traffic between the

cellular network and public switched networks or other MSCs

in the same or different cellular networks.

Monitoring The process of capturing information, either call

content or call set-up information or both, in real time

during he processing of a call. (This does not include

nonreal time access to stored data such as billing records

for previous calls or subscription parameters).

Multiple Agency Distribution The capability to provide

multiple surveillances of a given access to a target to

satisfy the needs of more than one government agency by some

appropriate means.

Multiplex (MUX) Use of a common channel to make two or more

channels. This is done either by splitting of the common

channel frequency band into narrower bands, each of which is

used to constitute a distinct channel (frequency division

multiplex), or by allotting this common channel to multiple

users in turn, to constitute different intermittent channels

(time division multiplex).

Packet Switching A system whereby messages are broken down

into smaller units called packets that are then individually

addressed and routed through the network.

Pen Register A device that records or decodes electronic or

other impulses that identify the numbers dialed or otherwise

transmitted on the telephone line to which such device is

attached. Pen Register is an archaic name that survived the

transition from pulse dialing to touch-tone dialing. The

recording device is now called a "Dial Number Recorder"

(DNR). The term does not include a device used by a service

provider for billing, or recording incidental to billing,

for communications services, or any device used by a service

provider for cost accounting in the course of business.

Private Branch Exchange (PBX) Small local telephone office,

either automatic or manually operated, serving extensions in

a business complex and providing access to the public

switched telephone network.

Remote Switch A switch associated with, and controlled by,

an exchange in a different location (host switch). Host

switches can serve several remote switches, and are

connected to the remotes with facility links.

Roaming When the subscriber initiates or receives a call in

other than his or her home service area.

Service Profile Information The set of features,

capabilities, and/or operating restrictions associated with

a subscriber, e.g., account code digits, alternate billing

digits, etc.

Service Switching Point (SSP) A specially designed switch

that contains Advanced Intelligent Network (AIN) switching

capabilities.

Stored Program Control Point (SPCP) A computer component

that stores many of the intelligent functions of an Advanced

Intelligent Network (AIN).

Surveillance The process of maintaining watch on a target,

on behalf of a single law enforcement agency, for the

occurrence of originating or terminating calls that must be

monitored or for any other activity that must be recorded,

such as administrative changes to the service parameters.

Surveillance Switch The circuit switch which identifies

calls made from or to the target and which performs

surveillance. This is normally the local exchange (or end-

office) serving that target.

Tandem Switch A switch that connects trunks to trunks.

Target An identifiable origination or termination of a

telecommunications call. The most common identifier is the

telephone number (or "DN") that a call is made to or from,

but other identifiers may also be used.

TDMA Time Division Multiple Access

Transmission The act of transferring a sign, signal,

writing, image, message, sound, data, or other form of

intelligence (information) from one location to another by a

wire, radio, electromagnetic, photo-electronic, or photo-

optical system.

Transparency The circumstances wherein the parties to a

communication and unauthorized individuals (i.e.,

individuals who are not involved in implementing and

maintaining the intercept) are unaware of ongoing electronic

surveillance.

Trap and Trace Device A device that captures the incoming

electronic impulses that identify the originating number of

an instrument or terminal from which electronic

communication is transmitted.

Trunk A circuit between two ranks of switching equipment in the same office, or between different switching centers or different central offices.

Verification The process whereby law enforcement can adequately demonstrate to a judge or jury that the number or other identifier (e.g., telephone number, electronic mail address) targeted for interception corresponds to the person or persons whose communications are being intercepted.

Visitor Location Register (VLR) The location register other than the Home Location Register (HLR) used by a Mobile Switching Center (MSC) to retrieve information for handling of calls to or from a visiting subscriber. The VLR may or may not be located within, and be indistinguishable from, an MSC. The VLR may serve more than one MSC.