Information Superhighway: An Overview of Technology Challenges (Chapter
Report, 01/23/95, GAO/AIMD-95-23).
To take advantage of emerging technologies to create, manage, and use
information that could be of strategic importance to the United States,
the administration has launched an initiative to guide industry's
development of the national information superhighway. While the
structure and services to be offered by the information superhighway
have not yet been determined, several critical technical challenges are
emerging. These include the necessity of ensuring data security and
protection of users' privacy: provision of a "seamless" web of features
that will require standards and common interfaces and protocols; and
measures to ensure reliability.
--------------------------- Indexing Terms -----------------------------
REPORTNUM: AIMD-95-23
TITLE: Information Superhighway: An Overview of Technology
Challenges
DATE: 01/23/95
SUBJECT: Computer networks
Computer security
Telecommunication
Proprietary data
Right of privacy
Interagency relations
Technology transfer
Confidential communication
IDENTIFIER: National Information Infrastructure Program
Internet
DOD Multilevel Information Systems Security Initiative
North American Dual-Mode Cellular System
High Performance Computing and Communications Program
Information Superhighway
*******************************************************************************
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Cover
========================================================================== COVER
Report to the Congress
January 1995
INFORMATION SUPERHIGHWAY - AN OVERVIEW
OF TECHNOLOGY CHALLENGES
GAO/AIMD-95-23
Information Superhighway
Abbreviations
========================================================================= ABBREV
AIN - advanced intelligent network
ARPA - Advanced Research Projects Agency
ATM - asynchronous transfer mode
B-ISDN - Broadband Integrated Services Digital Network
DOD - Department of Defense
FCC - Federal Communications Commission
GEO - geosynchronous Earth orbit
HPCC - High Performance Computing and Communications
Hz - Hertz
IDEA - international data encryption algorithm
IITF - Information Infrastructure Task Force
ISDN - integrated services digital network
Kbps - thousand bits per second
LAN - local area network
LEO - low Earth orbit
Mbps - million bits per second
NANP - North American Numbering Plan
NII - national information infrastructure
NIST - National Institute of Standards and Technology
NSA - National Security Agency
OSI - Office of Special Investigations
PCN - personal communications network
PCS - personal communication system
SAC - service access code
SONET - synchronous optical network
SS7 - Signaling System 7
VF - voice frequency
VSAT - very small aperture terminal
Letter
========================================================================= LETTER
B-259205
January 23, 1995
To the President of the Senate and the
Speaker of the House of Representatives
In light of the strategic importance of the information superhighway, we
summarized the socioeconomic, regulatory, and technical issues associated with
its development in a September 1994 report. The enclosed report focuses in
more detail on the major technical issues facing the industry and federal
regulators in planning and implementing the superhighway.
We are sending copies of this report to all Members of Congress; the Secretary
of Defense; the Secretary of Commerce; and the Chairman, Federal Communications
Commission. Copies will also be made available to others on request.
This report was prepared under the direction of Joel C. Willemssen, Director,
Information Resources Management/Resources, Community, and Economic Development
Issues, who can be reached at (202) 512-6253. Other major contributors to this
report are listed in appendix V.
Charles A. Bowsher
Comptroller General
of the United States
EXECUTIVE SUMMARY
====================================================================== Chapter 0
PURPOSE
-------------------------------------------------------------------- Chapter 0:1
To take advantage of emerging technologies to create, manage, and use
information that could be of strategic importance to the United States, the
administration has launched an ambitious initiative--known as the National
Information Infrastructure program--to guide industry's development of the
national information superhighway. The Congress, while sharing the
administration's vision, has been examining what impact the high stakes race
among the major industry players to carve out portions of the superhighway will
have on competition and service choices.
Because of the importance of the information superhighway, GAO initiated work
to identify the socioeconomic, regulatory, and technical issues associated with
this initiative in detail. GAO summarized these issues in a prior report.\1
This current report focuses in more depth on the pivotal technical
issues--security and privacy, interoperability, and reliability. Failure by
the private and public sectors to address these challenges could adversely
affect the future of the emerging information superhighway.
--------------------
\1 Information Superhighway: Issues Affecting Development (GAO/RCED-94-285,
Sept. 30, 1994).
BACKGROUND
-------------------------------------------------------------------- Chapter 0:2
The administration envisions the superhighway as a seamless web of
communications networks, computers, databases, and consumer electronics--built,
owned, and operated principally by the private sector--that will put vast
amounts of information at users' fingertips. It believes that the
superhighway, if freed from the constraints imposed by rigid regulatory
regimes, can fundamentally change the way we work, learn, get health care and
public services, shop, communicate, and entertain ourselves.
While initial versions of some of these advanced capabilities and services are
already provided by the existing infrastructure, albeit at relatively high cost
and low transmission speeds, much remains to be done to achieve the
superhighway's potential. For example, although some of the services
envisioned for the information superhighway are being provided by the Internet,
various on-line information services, and thousands of electronic bulletin
boards, these services are not ubiquitous, secure, or consistently user
friendly. Building the superhighway will require deploying and integrating
advanced communications technologies with the existing communications networks,
and investing tens of billions of dollars to build the "on ramps" to connect
residential, institutional, and business users.
The administration has formed a multiagency group--the Information
Infrastructure Task Force--to articulate a vision for the information
superhighway and to guide its development. The task force is examining a wide
range of technical issues relevant to the development and growth of the
superhighway.
RESULTS IN BRIEF
-------------------------------------------------------------------- Chapter 0:3
While the structure and services to be offered by the information superhighway
have not yet been determined, several critical technical challenges are
emerging. First, if it is to provide critical communications services to
manufacturing, health care, and other business sectors, the superhighway must
ensure data security and protect users' privacy. Because existing public
networks are largely unsecured and are vulnerable to damage from intruders,
achieving security and privacy will require careful and thoughtful design.
Second, the superhighway should provide a "seamless" web of features and
services to users, with thousands of systems and components interacting, or
interoperating, in a way that is transparent to users. Achieving
interoperability will require manufacturers to cooperate with standards-setting
bodies to establish common interfaces and protocols.
Third, to prevent network failures, the superhighway must be reliable,
end-to-end, from users to service providers. Recent outages on the existing
networks that will form the foundation for the superhighway have raised
concerns about achieving this goal.
PRINCIPAL FINDINGS
-------------------------------------------------------------------- Chapter 0:4
ENSURING SECURITY AND PRIVACY
WILL POSE A MAJOR CHALLENGE
------------------------------------------------------------------ Chapter 0:4.1
A large volume of the information that will traverse the superhighway will be
proprietary or privacy sensitive and therefore will need to be protected.
Unauthorized disclosure, theft, modification, or malicious destruction of such
information could bankrupt a business, interrupt vital public service, or
destroy lives. As it evolves, the infrastructure will likely become a tempting
target for intruders with the technical expertise and resources to cause great
harm. These intruders could include hackers, foreign governments conducting
political and military intelligence operations, domestic and foreign
enterprises engaged in industrial espionage, or terrorist groups seeking to
disrupt our society or cripple our economy.
Significant effort will be needed to define, develop, test, and implement
measures to overcome the security challenge posed by the development of the
superhighway. These measures include identifying the superhighway's security
and privacy requirements and developing tools and techniques to satisfy the
requirements.
The federal government, because of its extensive experience and expertise in
developing secure networks, could play a leading role in ensuring the
superhighway's security. However, critics of federal involvement argue that
current federal initiatives represent a danger to civil liberties, and that
individuals should be free to choose the technical means for achieving
information security. As a result, the challenge will be establishing a
reasonable level of consensus among the major players--the government, the
computer and communications industry, the business community, and civil liberty
groups--on how to ensure information security and privacy.
ACHIEVING INTEROPERABILITY IS A
CRITICAL GOAL
------------------------------------------------------------------ Chapter 0:4.2
An essential goal of the superhighway will be achieving interoperability among
the thousands of networks and components. Such interoperability is critical
for ensuring the delivery of seamless features and services to users.
Achieving this goal will be difficult because the components and services of
the superhighway will be designed, provided, and maintained by thousands of
suppliers. Further, ensuring interoperability will also require the
development and use of standards for voice, video, data, and multimedia
services. However, many of the standards needed to ensure the superhighway's
interoperability do not currently exist, while in other cases, systems,
including digital cellular system and some high-speed optical transmission
systems, are being deployed based on ill-defined, immature, or competing
standards. The federal and private sectors are beginning to deal with certain
aspects of network interoperability, such as the development of industry-wide
standards and the establishment of interoperability test beds.
NETWORK RELIABILITY IS EMERGING
AS A KEY CHALLENGE
------------------------------------------------------------------ Chapter 0:4.3
The superhighway will rely on complex hardware and software components to link
thousands of networks serving hundreds of millions of users worldwide. While
these components are beginning to provide a host of new services, they are also
becoming one of the largest causes of network failures. As fewer and fewer
components handle more and more connections, a failure of one component could
cause the loss of service for several million customers. In addition, the
introduction of new technologies and growth in the number of networks will
likely increase vulnerability. The government and industry have recently taken
steps, including the establishment of the Network Reliability Council and the
Networks Operations Forum, to address these issues.
RECOMMENDATIONS
-------------------------------------------------------------------- Chapter 0:5
Because this report is intended to serve as an overview of key technical
issues, it makes no recommendations.
AGENCY COMMENTS
-------------------------------------------------------------------- Chapter 0:6
GAO provided and discussed a draft of this report with officials from the
Federal Communications Commission, the National Telecommunications and
Information Administration, the Information Infrastructure Task Force, the
National Institute of Standards and Technology, the Department of Defense, the
Advanced Research Projects Agency, and the National Security Agency. These
officials generally agreed with the contents of this report. GAO incorporated
their comments where appropriate.
INTRODUCTION
====================================================================== Chapter 1
A global technological upheaval, fueled by rapid advances in information
processing, storage, switching, and transmission technologies, is beginning to
blur the lines between computing, telephony, television, and publishing. This
convergence is creating a new breed of information service industry, and
permitting the development of the much discussed National Information
Infrastructure (NII), commonly known as the information superhighway. The
administration envisions the superhighway as a seamless web of communications
networks, computers, databases, and consumer electronics--built, owned, and
operated principally by the private sector--that will put vast amounts of
information at users' fingertips. It believes that the superhighway, if freed
from the constraints imposed by rigid regulatory regimes, will fundamentally
change the way we work, learn, shop, communicate, entertain ourselves, and get
health care and public services.
Despite the dramatic advances in technology and the changes sweeping the
communications industry, the superhighway's development is expected to be slow
and arduous. As such, its development should not be viewed as a cliff that is
suddenly confronted, but rather an increasingly steep slope that society has
been climbing since the early communications networks were established.\1 A
national and global information infrastructure, which will serve as the
foundation for the superhighway, already exists. Telephones, televisions,
radios, computers, and fax machines--interconnected through a complex web of
fiber optics, wires, cables, satellites, and other communications
technologies--are used every day to receive, store, process, display, and
transmit data, text, voice, sound, and images in homes and businesses
throughout the world. However, the information superhighway is expected to
offer much more than separate telephone, data, or video services; it is
expected to integrate these services into an advanced high-speed, interactive,
broadband, digital communications system.\2
Some of the advanced capabilities and services envisioned for the superhighway
are beginning to be provided--albeit at a relatively high cost and at low
transmission speeds--by the existing information infrastructure. For example,
the Internet--a global metanetwork, or "network of networks," linking over
59,000 networks, 2.2 million computer systems, and over 15 million users in 92
countries--provides many of the services envisioned for the information
superhighway.\3 Similarly, a growing number of on-line services, such as
CompuServe, America Online, and Prodigy, provide their subscribers with a rich
array of information services. Finally, hundreds of communities across America
are served by electronic bulletin boards dispensing information to hundreds of
thousands of users.
The administration, believing that the technologies to create, manipulate,
manage, and use information are of strategic importance to the United States,
has formed a multiagency group--the Information Infrastructure Task Force
(IITF)--to articulate a vision for the information superhighway and to guide
its development. The task force, chaired by the Secretary of Commerce, is
responsible for addressing a wide range of regulatory and technical issues
related to the information superhighway and for the coordination of existing
federal efforts in the communications area. The task force is examining,
through its committees and working groups, a wide range of technical issues
relevant to the development and growth of the information superhighway. A more
detailed description of the IITF structure and its activities is presented in
appendix I.
--------------------
\1 What it Takes to Make It Happen: Key Issues for Applications of the
National Information Infrastructure, Committee on Applications and Technology,
Information Infrastructure Task Force, January 25, 1994.
\2 In digital networks, analog messages (such as voice) are converted to
digital signals (ones and zeroes). Once in digital form, voice, video,
graphics, and text can be combined and efficiently stored, compressed, and
transmitted. The capacity of a digital network may be described in terms of
the number of bits that the network can transmit every second. In general,
narrowband networks transmit at rates below 1.5 million bits per second (1.5
Mbps); broadband networks transmit at rates above 1.5 Mbps.
\3 Internet users with access to a transmission speed of 56 thousand bits per
second (56 Kbps) can receive digital radio or transmit and receive digital
files containing embedded text, voice, video, and images. However, at current
commercial rates, the average fee for attachment to the Internet at 56 Kbps is
about $15,000 per year. Users not requiring sophisticated multimedia services
may access Internet for about $25 per month.
THE GRAND VISION OF THE INFORMATION
SUPERHIGHWAY
-------------------------------------------------------------------- Chapter 1:1
While industry is beginning to build the information superhighway, little is
known about how the superhighway will be structured and what services it will
provide. Nevertheless, a common vision of its capabilities is beginning to
form among policymakers and public interest groups. First, there is an
emerging agreement that the superhighway should be structured as a metanetwork
that will seamlessly link thousands of broadband digital networks. Second, it
should allow a two-way flow of information, with users being able to both
receive and transmit large volumes of digital information. Third, it should be
open, ensuring equal access for service and network providers. Finally, it
should ensure the security and privacy of databases and users' communications,
and provide a high degree of interoperability and reliability.
Achieving the grand vision will depend largely on how successfully industry
integrates advanced technologies and capabilities into the various layers of
the information superhighway. To better understand the integration of advanced
telecommunication technologies into the existing communication infrastructure,
we developed a conceptual model of the information superhighway, as shown in
figure 1.1.
Figure 1.1: Functional Layers of
the Information Superhighway
(See figure in printed edition.)
The model presents the following five critical layers--management,
applications, information, networks, and transport--linked with pervasive
security, interoperability, and reliability requirements:
the transport layer consists of optical fibers, coaxial cable, copper wire,
switches, routers, satellites, and transmitters
the networks layer consists of thousands of logical networks superimposed on
the transport layer
the information layer includes databases and electronic libraries containing
text, images, and video
the applications layer contains software and consumer electronics needed to
access the superhighway's information and services
the management layer consists of operations and administrative centers,
emergency response teams, and security services.
TODAY'S NETWORKS PROVIDE THE
FOUNDATION FOR THE SUPERHIGHWAY
------------------------------------------------------------------ Chapter 1:1.1
With a few exceptions, such as the recently proposed global satellite networks,
most experts anticipate that the superhighway will be built on the foundation
of the existing communications infrastructure. Over the years, this
infrastructure has evolved into three separate, and frequently incompatible,
communications networks.\4 These are
the wire-based voice and data telephone networks,
the cable-based video networks, and
the wireless voice, data, and video networks.
The wire-based voice and data telephone networks are part of the global
telephone network.\5 The voice networks provide ubiquitous, highly
interoperable, high-speed, and flexible telephone service to millions of users.
The data networks provide high-speed digital data communications services. The
cable-based video networks rely on various approaches to broadcast a one-way
broadband video signal to individual subscribers. Finally, the wireless
networks use a wide range of analog and digital radio technologies to deliver
voice, data, and video services.
The principal shortcoming of the existing communications infrastructure is its
inability to provide integrated voice, data, and video services. Over the
years, the voice and data networks have evolved separately, with voice networks
relying on circuit switching while data networks largely using packet switching
techniques. Thus, a business user requiring voice, data, and videoconferencing
services may have to use three separate networks--a voice network, a data
network, and a videoconferencing network. The emergence of multimedia
applications and the high bandwidth applications in health care, industry,
education, and business are beginning to require a network infrastructure
capable of supporting multiple types of information.
The basic architecture of the three types of networks is shown in figure 1.2
(see appendix II for an overview of each of these networks).
Figure 1.2: Telephone, Cable, and
Wireless Networks
(See figure in printed edition.)
The communications industry is beginning to introduce several new and
innovative technologies that could enable the superhighway's developers to
achieve the administration's vision of the information superhighway. These
technologies include
narrowband Integrated Services Digital Network (ISDN),
advanced signaling and intelligent networks,
broadband ISDN (B-ISDN),
personal communications networks, and
broadband in the local loop.
These technologies, described in more detail in appendix III, will help provide
many of the advanced services and capabilities of the information superhighway.
The development of the superhighway will also require the expenditure of tens
of billions of dollars to build the local broadband "on-ramps" connecting
residential, institutional, and business users with the evolving
superhighway.\6 Further, its users are expected to be offered viable services
and information products beyond the much touted 500 channels of high-definition
television.\7
--------------------
\4 An additional type of data network--the fiber optic networks used by
electric power utilities to manage their power distribution systems--also
exists. These networks may eventually become part of the information
superhighway.
\5 Unlike the private networks developed for the exclusive use of one
organization, the U.S. common carrier networks are shared-resource networks
that offer communications services to public subscribers.
\6 Cable Television Laboratories estimates that the replacement of the copper
wire in the local loop will cost hundreds of billions of dollars.
\7 Many argue that once the industry provides the on-ramps, a rich array of
services requiring interactive, broadband transmission capabilities will be
developed. Others believe that the response to the view "if we build it, they
will come" is "yes, but will they bring any money?"
OBJECTIVE, SCOPE, AND METHODOLOGY
-------------------------------------------------------------------- Chapter 1:2
In light of the strategic importance of the information superhighway, we
identified the socioeconomic, regulatory, and technical issues and challenges
associated with the development of the information superhighway. Our previous
report addressed all three areas.\8 Our objective in this report is to address
in more detail the key technical issues: security and privacy,
interoperability, and network reliability.
To accomplish our objective, we surveyed an extensive body of technical
literature and industry journals, searched and reviewed related documents from
Internet networks, and reviewed postings to various Internet news groups with
interest in telecommunications and information security issues. To obtain the
views of federal officials on the technical challenges related to the
development of the information superhighway, we met with representatives from
the Federal Communications Commission (FCC), the National Telecommunications
and Information Administration, the Information Infrastructure Task Force
(IITF), the National Institute of Standards and Technology (NIST), the National
Science Foundation, the Department of Defense (DOD), the Advanced Research
Projects Agency (ARPA), and the National Security Agency (NSA). We also met
with representatives of the telephone, cable, and communication industry to
obtain their views on technical issues related to the superhighway.
We conducted our work in Washington, D.C., and vicinity between September 1993
and October 1994, in accordance with generally accepted government auditing
standards. In addition, we discussed the contents of this report with
representatives of the National Telecommunications and Information
Administration, IITF, FCC, NIST, DOD, ARPA, and NSA, and have incorporated
their comments where appropriate.
--------------------
\8 Information Superhighway: Issues Affecting Development (GAO/RCED-94-285,
Sept. 30, 1994).
ENSURING SECURITY AND PRIVACY WILL POSE
A MAJOR CHALLENGE
====================================================================== Chapter 2
Much of the information that will be on the superhighway, including health care
records, business documents, engineering drawings, purchase orders, or credit
card transactions, will be proprietary or privacy sensitive and must be
protected. As it evolves, the superhighway will become an increasingly
tempting target for intruders with the technical expertise and resources to
cause great harm, including insiders,\1 hackers, foreign governments conducting
political and military intelligence operations, domestic and foreign
enterprises engaged in industrial espionage, and terrorist groups seeking to
disrupt our society or cripple our economy.\2 Unauthorized disclosure, theft,
modification, or malicious destruction of such information could bankrupt a
business, interrupt vital public service, or destroy lives.
Information security plays a key role in protecting computer systems, networks,
and information--including voice, fax, and data communications--from harm,
disclosure, or loss. Privacy depends heavily on security.\3 In essence, there
is little or no privacy protection afforded by poorly secured information
systems and networks. While privacy-enhancing legislation, regulations, and
management practices play an important role in reducing the threat to
individual privacy, it is security technology that will provide many of the
safeguards.\4
Significant effort will be needed to define, develop, test, and implement
measures to overcome the security challenge posed by the increasing complexity,
interconnectivity, and the sheer size of the evolving superhighway. These
measures include identifying the superhighway's security and privacy
requirements and developing tools and techniques to satisfy the requirements.
The federal government, because of its extensive experience and expertise in
developing secure networks, is addressing selected aspects of security and
privacy. However, critics of federal involvement argue that the current
federal strategy represents a danger to civil liberties and that individuals
should be free to choose the technical means for achieving information
security. As a result, the challenge will be establishing a reasonable level
of consensus among the major players--the government, the computer and
communications industry, the business community, and civil liberty groups--on
how to ensure information security and privacy on the information superhighway.
--------------------
\1 Many violations of information safeguards are perpetrated by trusted
personnel who engage in unauthorized activities or activities that exceed their
authority. These insiders may copy, steal, or sabotage information, yet their
actions may remain undetected.
\2 Economic Espionage: The Threat to U.S. Industry (GAO/T-OSI-92-6, Apr. 29,
1992).
\3 Privacy is the state of being free from unsanctioned intrusion; a condition
in which an individual can determine when, how, and to what extent information
about him or her is collected, used, and communicated to others.
\4 Information Security and Privacy in Network Environments, Office of
Technology Assessment, Washington, D.C: September 1994.
NETWORKS AND COMPUTER SYSTEMS ARE
INCREASINGLY VULNERABLE TO ATTACKS
-------------------------------------------------------------------- Chapter 2:1
The vulnerability of interconnected computer systems is periodically
highlighted by attacks on the thousands of computer systems connected to the
Internet. These attacks provide an important lesson. The Internet--the
world's largest network of networks--has many of the same attributes that will
eventually be found in the information superhighway. The information
superhighway may not only share similar vulnerabilities, but it may face
similar, albeit greatly magnified, threats.
Two major security incidents affecting the Internet illustrate the risk to the
evolving information infrastructure. On November 8, 1988, thousands of
computers connected to the Internet were attacked by a worm.\5 While the worm
did not damage or compromise data, it did deny service to thousands of users
working at the nation's major research centers. We found that a number of
vulnerabilities facilitated this attack, including the lack of a central focal
point to address Internet-wide security problems; security weaknesses at host
computer sites; and problems in developing, distributing, and installing
software patches to operating system software.\6 In response to this incident,
the Advanced Research Projects Agency established a Computer Emergency Response
Team to assist the Internet community in responding to attacks. Several
federal agencies and private-sector organizations also established additional
computer emergency response teams coordinated by NIST.
Five years later, in January 1994, intruders again exploited similar
weaknesses. This time, the attack was more serious. The intruders gained
access to a number of hosts (computer systems) linked to the Internet. The
intruders then installed software that captured user names, passwords, and
hosts' addresses for Internet traffic terminating at, or passing through, the
attacked sites. In addition, they installed two Trojan horse programs,\7 one
program to provide back-door access for the intruders to retrieve the captured
passwords, and a second program to disguise the network monitoring process.
With this information, the intruders could access 100,000 Internet accounts.\8
The Department of Defense reported that the attacks compromised a major portion
of the international commercial networks as well as major portions of the
unclassified Defense information infrastructure. Defense functions affected by
the attacks included ballistic weapons research, ocean surveillance, and the
military health care systems.
--------------------
\5 Worms are self-contained programs containing malicious code that copy
versions of themselves across electronically connected nodes.
\6 Computer Security: Virus Highlights Need for Improved Internet Management,
(GAO/IMTEC-89-57, June 12, 1989).
\7 A Trojan horse is a program that conceals malicious computer code.
Typically, a Trojan horse masquerades as a useful program that users would want
or need to execute. It performs, or appears to perform, as expected, but also
does surreptitious harm.
\8 Computer Incident Advisory Capability team, Department of Energy.
SECURITY MEASURES ARE CRITICAL TO
MINIMIZING RISK
-------------------------------------------------------------------- Chapter 2:2
Reducing the frequency and damage of attacks against the national networks will
require a significant effort to provide the tools and resources necessary for
the development and deployment of infrastructure-wide security services. These
services include
identification and authentication--the ability to verify a user's identity and
a message's authenticity,
access control and authorization\9 --the protection of information from
unauthorized access,
confidentiality--the protection of information from unauthorized disclosure,
integrity--the protection of information from unauthorized modification or
accidental loss,
nonrepudiation--the ability to prevent senders from denying they have sent
messages and receivers from denying they have received messages, and
availability--the ability to prevent denial of service, that is, to ensure that
service to authorized users is not disrupted.
Cryptography\10 will play a key role in the development of five of the six
security services for the information superhighway. It helps, through password
encryption, to improve identification and access control; it protects
confidentiality and data integrity by encrypting the data; and finally, it
improves, through encrypted electronic signature and related means,
nonrepudiation services.
Two basic types of cryptographic systems exist: secret key systems (also
called symmetric systems) and public key systems (also called asymmetric
systems).\11 In secret key cryptography, two or more parties use the same key
to encrypt and decrypt data. As the name implies, secret key cryptography
relies on keeping the key secret. If this key is compromised, the security
offered by cryptography is eliminated. The best known secret key algorithm is
the Data Encryption Standard. It is currently the most widely accepted,
publicly available symmetric cryptographic algorithm. Secret key systems also
require that a secure communications channel be established for the delivery of
the secret key from the sender to receiver. Such a secure, nonelectronic
communications channel for the distribution of secret keys is costly to
establish and maintain.
Unlike secret key cryptography, which employs a single key shared by two or
more parties, public key cryptography uses a pair of matched keys for each
party. One of these keys is public and the other private. The public key is
made known to other parties--mainly through electronic directories--while the
private key must be kept confidential. Thus, under the public key system,
there is no need to establish a secure channel to distribute keys. The sender
encrypts the message with the recipient's freely disclosed, unique public key.
The recipient, in turn, uses her unique private key to decrypt the message.
Public key cryptography also enables the user to produce an electronic
signature. The user encrypts the signature using the private key, which, when
decrypted with the public key, provides verification that the message
originated from that user. The best known public key algorithm is the
Rivest-Shamir-Adelman algorithm.\12 The Pretty Good Privacy software, which
implements the Rivest-Shamir-Adelman algorithm, is probably one of the best
known public key cryptographic systems.\13 Figure 2.1 highlights the principal
features of the secret and public key cryptographic systems.
Figure 2.1: Secret and Public Key
Encryption Systems
(See figure in printed edition.)
A host of related security technologies, including computer memory cards, will
also play an important role in securing the information superhighway. Computer
memory technology uses a credit-card-size electronic module to store digital
information that can be recognized by a network or a host system. Figure 2.2
shows a computer memory card--the Tessera Crypto Card--developed by the
National Security Agency.\14 The Tessera Crypto Card is a small, portable
cryptographic module that provides high-speed authentication and encryption
services.
Figure 2.2: Tessera Crypto Card
--------------------
\9 Authorization involves two steps--identification and authentication.
\10 Cryptography is a technique for transforming ordinary text (plaintext) into
unintelligible ciphertext through encryption.
\11 A key is a unique sequence of letters, numbers, or combination of both that
is used to encrypt and decrypt messages.
\12 Rivest-Shamir-Adelman is a public key algorithm used for both encryption
and authentication; it was invented in 1977 by Ron Rivest, Adi Shamir, and
Leonard Adelman.
\13 The Pretty Good Privacy is a public key cryptographic system developed by
Philip Zimmerman.
\14 The Tessera crypto card, based on the Personal Computer Memory Card
International Association Industry standard, was recently renamed Fortezza.
The card is a key element of the Department of Defense's Multilevel Information
Systems Security Initiative.
FEDERAL ROLE IN SECURITY AND PRIVACY
IS SUBJECT TO DEBATE
-------------------------------------------------------------------- Chapter 2:3
Federal involvement in communication security is fueling a debate over the
federal role in regulating the development and use of encryption and
communications technologies. Critics of federal involvement, such as the
Electronic Frontier Foundation--a public interest organization focused on
protecting civil liberties in digital environments--believe that government
control of encryption technologies and their implementation represents a danger
to civil liberties, and that individuals should be free to choose the technical
means for meeting their security requirements. Others, including NIST and
Defense officials, maintain that the federal government's participation and
guidance in securing the information superhighway may be needed for several
reasons. First, the government is a major consumer of telecommunications
services and has unique national security and law enforcement needs that must
be addressed. Second, the government, and particularly the Department of
Defense, has considerable experience in the areas of computer and
communications security. Defense, the developer and operator of the world's
largest secure communications network, could provide expertise needed to help
develop the superhighway's security architecture. The need for such an
architecture was underscored by a recent study which noted that it is
"imperative to develop at the outset a security architecture that will lay the
foundation for protections of privacy, security, and intellectual property
rights--safeguards that cannot be supplied as effectively on an add-on
basis."\15
Since the invention of the telegraph and telephone, intelligence and law
enforcement agencies have conducted legal intercepts of communications both
here and abroad. In general, these agencies used technically simple intercepts
that targeted unprotected communications. However, the emergence of digital
technologies and the increased availability of sophisticated encryption tools
has dramatically eroded the government's electronic intelligence and analysis
capabilities. The proliferation of digital communications is making
wiretapping increasingly difficult, while robust encryption prevents third
parties, including law enforcement and intelligence agencies, from deciphering
and understanding intercepted messages.
The administration, after coordination with the Congress, industry, and public
advocacy groups, has developed a strategy designed to preserve the government's
ability to conduct electronic surveillance, wiretapping, and analysis of voice
and data communications between criminals, terrorists, drug dealers, and
foreign agents. This strategy includes
a major new federal cryptography initiative known as the Key Escrow Standard
(popularly known as the "Clipper chip" program),
the Communications Assistance for Law Enforcement Act requiring the information
industry to provide "built-in" wiretapping support in its digital
communications systems, and
restrictions on the export of encryption technology.
--------------------
\15 Realizing the Information Future, National Research Council, National
Academy Press.
Washington, D.C.: 1994, p. 5.
KEY ESCROW INITIATIVE INTENDED TO
IMPROVE COMMUNICATION SECURITY
------------------------------------------------------------------ Chapter 2:3.1
The Key Escrow initiative is a voluntary program to improve the security and
privacy of telephone communications in the private sector while meeting the
legitimate needs of law enforcement. In essence, the initiative is the
government's attempt to preempt the threat posed by sophisticated encryption
capabilities by offering the industry a relatively inexpensive, albeit
government-controlled, hardware-based encryption system capable of providing
secure voice, fax, and data services. To ensure that law enforcement agencies
are able to understand Clipper-encrypted voice communications, the private
encryption keys assigned to each individual Clipper chip are to be escrowed
with the government. These keys will be made available to law enforcement
agencies for court-ordered wiretaps.
The Clipper chip, developed by NSA, is a microcircuit incorporating a
classified encryption algorithm known as Skipjack.\16 The chip, and its close
relative, the Capstone chip, contain a unique key that is used to encrypt and
decrypt messages, programmed by the escrow agents.\17 This unique key is then
split into two components and delivered to two federal agencies--or escrow
agents--for safekeeping. When federal authorities encounter Clipper chip
encrypted voice or Capstone chip encrypted data communications during the
course of court-authorized wiretapping, they may obtain the unique key
necessary for the decryption of the wiretapped communications from the escrow
agents. Figure 2.3 shows a Capstone chip and three prototypes of a Clipper
chip.
Figure 2.3: The Capstone and the Clipper Chips
Source: National Security Agency.
In April 1993, the President directed the Attorney General to (1) request
manufacturers of communications hardware that incorporates encryption to
install the Clipper chip in their products, and (2) designate two government
organizations as "key escrow" holders. The President also directed the
Secretary of Commerce to initiate, through NIST, a process to develop federal
key escrow encryption standards. Despite strong industry opposition,\18 the
administration reaffirmed its 1993 directive and instructed the Secretary of
Commerce to approve the Clipper chip as a voluntary national standard for
encrypted telephone communications. In February 1994, NIST formally approved
the new standard. At the same time, the Attorney General designated NIST and
the Automated Systems Design Division of the Department of the Treasury as the
key escrow agents.
Critics of the Key Escrow initiative argue that NSA's refusal to declassify and
publish the Skipjack encryption algorithm raises the possibility that the
algorithm may have a built-in "trap door."\19 Such a trap door would allow
intelligence agencies to decrypt Clipper and Capstone encrypted communications
at will, without obtaining the private keys from the escrow agents.\20 The
critics also note that since robust encryption technology is available both in
the U.S. and abroad, there is no incentive for domestic and international
industry or private citizens to adopt the Clipper/Capstone technology.
The misgivings about the Key Escrow initiative were also shared by the Computer
System Security and Privacy Advisory Board.\21 In its
June 4, 1993, resolution, the Board stated that the administration has not (1)
provided a convincing statement of the problem that Clipper attempts to solve,
(2) considered other escrow alternatives including the designation of a third,
non-government escrow agent, and (3) fully examined the legal and economic
implications of the Clipper chip initiative. The Board recommended that the
Key Escrow encryption technology not be deployed beyond current implementations
planned within the Executive Branch until the significant public policy and
technical issues inherent with this encryption technique are fully understood.
The Congress asked the National Research Council to conduct a comprehensive
study of national cryptography policy and submit, within 2 years, a report to
the Secretary of Defense.\22 In December 1993, the Board endorsed the proposal,
noting that the study should be conducted as quickly as possible.
In July 1994, the administration reaffirmed its commitment to the Key Escrow
scheme in general, and to the use of the Clipper chip for telephone
communications in particular. It also offered a compromise on the development
of the Capstone chip for computer and video networks. Specifically, the
administration said that it understood the concerns that industry has regarding
the Capstone chip and welcomed the opportunity to work with industry to design
a more versatile, less expensive system. NIST and the information security
industry have now initiated a joint effort to explore alternative approaches.
Such alternative key escrow schemes would be implemented in software, firmware,
or hardware, or a combination thereof; would not rely on a classified
algorithm; would be voluntary; and would be exportable.\23
--------------------
\16 The power of the Clipper chip technology is highlighted by comparing it to
earlier voice encryption devices. For example, in the early 1940s, the
administration asked scientists at the Bell Telephone Laboratories to develop a
telephone scrambler that would allow Winston Churchill and President Roosevelt
to have secure conversations. Code named "Sigsaly," this transatlantic
scrambler needed, at the London end, not only a five foot high intermediate
scrambler cabinet, but also over 30 seven foot tall relay racks weighing eighty
tons, 72 different radio frequencies, a large air-conditioned room, and 30 kW
of energy to encipher one short conversation (The Cabinet War Rooms, Imperial
War Museum, London, 1994).
\17 The Clipper chip is designed to encrypt voice transmission; the Capstone
chip is designed to encrypt data and video transmission.
\18 In July 1993, NIST asked industry to comment on the proposed standard. Of
the 320 respondents, only 2 supported the proposed standard.
\19 A trap door is a hidden software or hardware mechanism that allows systems
controls to be circumvented. Software developers often introduce trap doors in
their code to enable them to reenter the system later and perform certain
functions.
\20 On more than one occasion, administration officials, including the Deputy
Director of NIST, have testified before Congress that the Skipjack algorithm
does not incorporate a trap door mechanism.
\21 The Board, composed of representatives from the computer and
telecommunications industry, independent experts in telecommunications, and
federal employees, was established by the Computer Security Act of 1987 to
advise the Secretary of Commerce and the Director of NIST on security and
privacy issues.
\22 Public Law 103-160, Section 267.
\23 Letter from Vice President Al Gore to the Honorable Maria Cantwell, House
of Representatives, July 20, 1994.
LEGISLATION ENACTED TO FACILITATE
DIGITAL WIRETAPS
------------------------------------------------------------------ Chapter 2:3.2
To address concerns about the potential loss of wiretapping capability due to
the rapid deployment of digital communications,\24 in October 1994 the Congress
enacted the Communications Assistance for Law Enforcement Act.\25 The act
requires common carriers to ensure that they posses sufficient capability and
capacity to accommodate law enforcement's wiretapping needs. Specifically, the
act requires that telecommunications carriers develop the capability to
expeditiously isolate the content and call-identifying information of a
targeted communication and enable the government to access targeted
communication at a point away from the carrier's premise. The act requires the
government to reimburse carriers for all reasonable costs associated with
complying with the act's requirements. Critics of the act--including the
Electronic Frontier Foundation--argue that it further erodes communication
privacy, and that the Federal Bureau of Investigation has not adequately
documented its need for sophisticated digital wiretap capability.
--------------------
\24 Electronic Surveillance: Technologies Continue to Pose Challenges
(GAO/T-AIMD-94-173,
Aug. 11, 1994).
\25 Public Law 103-414.
FEDERAL GOVERNMENT RESTRICTS THE
EXPORT OF ENCRYPTION TECHNOLOGY
------------------------------------------------------------------ Chapter 2:3.3
Many of the U.S. encryption technologies, whether developed commercially or by
the government, are subject to export controls. The Departments of State and
Commerce share responsibility for controlling the exports of these
technologies.\26 However, computer industry representatives view the encryption
export controls as counterproductive and economically damaging. For example,
the representatives noted that because robust, sophisticated encryption
technologies, including technologies on the U.S. Munitions List, are widely
available in foreign markets, the export controls are reducing their
international sales.\27
Our brief search of foreign Internet sites confirms industry's assertion that
sophisticated encryption software is widely available to foreign users. For
example, we found that a number of European Internet sites are offering
U.S.-made encryption software. In less than two hours, we identified several
European sites offering the Pretty Good Privacy software, obtained it from an
Internet site in Great Britain, installed the software on our computer, and
encrypted a message (shown in figure 2.4).
Figure 2.4: Message Encrypted With
the Pretty Good Privacy Encryption
System
(See figure in printed edition.)
--------------------
\26 Certain encryption products are placed on the U.S. Munitions List. These
products require a munitions license for export to foreign countries.
\27 Communications Privacy: Federal Policy and Actions, (GAO/OSI-94-2, Nov.
4, 1993).
ACHIEVING INTEROPERABILITY IS A
CRITICAL GOAL
====================================================================== Chapter 3
Interoperability--the ability of two or more components of a system or network
to interact with each other in a meaningful way--is a key goal of the
information superhighway. However, full interoperability among the thousands
of networks, communications devices, and services that will comprise the
information superhighway will be difficult to achieve. To do so, governments,
industry, and standards-setting organizations must agree on well-defined
international standards for rapidly advancing communications technologies,
while manufacturers and service providers need to provide products and services
conforming to these standards. However, the telecommunications industry is
already deploying, or plans to deploy, a host of technologies and services that
are based on ill-defined, anticipatory, or competing standards. To address
this dilemma, the federal and private sectors have initiated interoperability
efforts, including the assessment of various "open network" architectures.\1
--------------------
\1 The National Research Council defines an open network as one that is capable
of carrying information services of all kinds, from suppliers to customers,
across network service providers of all kinds, in a seamless, accessible
fashion.
INTEROPERABILITY WILL BE DIFFICULT
TO ACHIEVE
-------------------------------------------------------------------- Chapter 3:1
Interoperability will define the information superhighway. Without
interoperability, the information superhighway will be fragmented into
thousands of poorly integrated communications networks providing a bewildering
choice of incompatible services. While policymakers, public interest groups,
and industry agree that interoperability is a key requirement, they also agree
that it will be difficult to achieve among the thousands of communications
networks, computers, databases, and consumer electronics that will comprise the
information superhighway. As discussed in chapter 1, the existing
infrastructure suffers from significant interoperability problems.
NEW TECHNOLOGIES BEING DEPLOYED
ARE BASED ON ILL-DEFINED,
ANTICIPATORY, AND COMPETING
STANDARDS
------------------------------------------------------------------ Chapter 3:1.1
Because of competitive pressures, the desire to provide new capabilities, and a
belief that the traditional standards-setting process is unable to keep up with
the fast pace of technological change, industry is deploying, or is planning to
deploy, a host of new technologies and services. However, many of these
technologies and services are based on ill-defined, anticipatory, or competing
standards, thereby further complicating efforts to achieve interoperability.
The effects of deploying new technology based on ill-defined standards is
illustrated by the implementation of the ISDN. ISDN is an end-to-end digital
network evolving from the existing telephone network. It is viewed as the
first step in the conversion to a fully digital network. However, the initial
deployment of ISDN resulted in the proliferation of "island" ISDN services that
could not interoperate because the ISDN standards provided only a broad outline
and lacked enough detail to ensure that all implementations would be identical.
For example, ISDN users in New York and New England are unable to communicate
data with ISDN users in the middle atlantic states. To alleviate the ISDN
interoperability problems, the industry announced a plan to establish a
consistent interface that would provide interoperability between local
telephone companies, long distance telephone companies, and equipment
manufacturers.
The deployment of the Asynchronous Transfer Mode (ATM) services provides an
example of a technology deployed based on anticipatory standards. The
broadband ISDN (B-ISDN) technology, which is expected to lay the foundation for
the superhighway's interactive, high-speed digital communications
infrastructure, will rely on ATM/SONET optical fiber networks.\2 However,
critical ATM standards including global routing and addressing, resource
management, multicast,\3 and network management remain undefined. The industry
is also developing products and services in the absence of less visible, but
equally important standards, for data display and exchange, accounting and
billing, network addressing and naming, and telephone number portability (see
appendix IV).
The introduction of competing technologies is highlighted by the deployment of
digital cellular systems. Digital cellular systems are viewed as a key
component of the evolving personal communications networks. While digital
systems will offer dramatically better performance than their analog
counterparts, their near-term value in serving as a key link in the emerging
B-ISDN network is reduced by compatibility problems. There are three principal
digital cellular standards--the U.S. standard, known as the North American
Dual-Mode Cellular System; the European standard, known as Global System for
Mobile Communications; and the Japanese Digital Cellular standard. Although
all three standards are based on the time division multiple mode access
technique,\4 they are not interoperable.
--------------------
\2 ATM is a fast packet switching technology utilizing small, fixed-size cells.
Synchronous Optical Network (SONET) is the U.S. implementation of an
international synchronous digital hierarchy standard for optical carrier
networks.
\3 Multicast is a variant of broadcast, where information can be sent to
selected recipients instead of all subscribers of a particular communications
systems.
\4 A digital encoding scheme that allows users to simultaneously transmit on
the same frequency by allocating each user a discrete time slot.
THE FEDERAL AND PRIVATE SECTORS HAVE
INITIATED EFFORTS TO ADDRESS
INTEROPERABILITY
-------------------------------------------------------------------- Chapter 3:2
While the key players--the federal government, the computer and communication
industries, and various user groups--appear to agree on the need for a fully
interoperable information superhighway, there is no agreement yet on how it
should be achieved. The principal federal organizations focused on
superhighway interoperability include NIST and the National Research Council's
Computer Science and Telecommunications Board.\5 The overall coordination of
federal interoperability efforts is being examined by IITF's Technology Policy
Working Group. In the private sector, the FCC is working with industry to
ensure the interoperability of selected technologies deployed in public
networks. Industry has also established a consortium for the development and
testing of superhighway applications.
--------------------
\5 The federal interagency High Performance Computing and Communications
program is also addressing a wide range of network interoperability issues.
NATIONAL RESEARCH COUNCIL
ADVOCATES HIGH-LEVEL ARCHITECTURE
TO GUIDE INTEROPERABILITY EFFORTS
------------------------------------------------------------------ Chapter 3:2.1
One promising approach to the planning for interoperability is to develop a
high-level architecture--or framework--of the superhighway. This approach was
advocated by a recent National Research Council report that presented a vision
of the superhighway based on an open data network concept.\6 Under this
concept, the superhighway must be
open to users: it does not force users into closed groups or deny access to
any sector of society, but permits universal connectivity, as does the
telephone system,
open to service providers: it provides an open and accessible environment for
competing commercial or intellectual interests, including information
providers,
open to network providers: it makes it possible for any network providers to
meet the necessary requirements to attach and become a part of the aggregate of
interconnected networks, and
open to change: it permits the introduction of new applications and services
over time; it also permits the introduction of new transmission, switching, and
control technologies as these become available.
This concept, expressed as a high-level network architecture, could provide a
set of specifications to guide the detailed design of the information
superhighway. Without such a framework, the pieces of the emerging
superhighway may not fit together. The IITF's Technology Policy Working Group
is planning to examine the open data network concept and its applicability to
various industries, including cable television, broadcasting, communications
and computer.
--------------------
\6 Realizing the Information Future, National Research Council, National
Academy Press. Washington, D.C.: 1994.
INDUSTRY RESPONDS TO
INTEROPERABILITY PROBLEMS
------------------------------------------------------------------ Chapter 3:2.2
In an attempt to improve interoperability, the Network Operation Forum of the
Alliance for Telecommunications Industry Solutions established the Internetwork
Interoperability Test Plan Ad Hoc Committee. However, the committee's effort
was limited to solving problems with the Signaling System 7 (SS7)\7 switching
systems. The requirements for intranetwork, product-to-product, and
stand-alone equipment modeling and testing were considered to be outside of the
committee's charter. Other aspects of existing networks such as
interoperability testing requirements of newer technologies were also not
addressed. So far, the committee has developed scenarios designed to test the
interoperability of SS7 systems.
--------------------
\7 SS7 is an international common-channel signaling system.
NETWORK RELIABILITY IS EMERGING AS A
KEY CHALLENGE
====================================================================== Chapter 4
Ensuring the reliability\1 of the information superhighway will be essential.
The public and private sectors are increasingly dependent on the existing
telecommunications networks, which will be the foundation of the information
superhighway, to meet their business needs. Yet recent outages on these
networks have raised concerns and caused economic losses. Moreover, new
technologies and industry trends will likely increase network vulnerability,
making reliability of the superhighway a key challenge. The government and
industry have recently taken several steps to address reliability, including
the formation of the Network Reliability Council and the Alliance for
Telecommunications Industry Solutions.
--------------------
\1 Reliability is the probability that a system will not fail over a given
period of time and under specified conditions. It is based on the combined
reliability of all of the components that make up the system, their
interconnections, and the environment in which the system operates.
RELIABILITY OF THE SUPERHIGHWAY WILL
BE ESSENTIAL
-------------------------------------------------------------------- Chapter 4:1
In providing critical commercial and personal services, the superhighway will
require a highly reliable network. The nation is already dependent on the
existing networks, which will provide the underpinning for the superhighway.
For example, in addition to conventional telephone services, computers are
networked together, facsimile machines provide almost instant access to images
and documents, and teleconferencing and videoconferencing have emerged as
substitutes for travel. The number of electronic transactions conducted over
these networks is enormous. For example, the value of the telephone
transactions that take place daily on Wall Street exceeds one trillion dollars.
Similarly, the Federal Aviation Administration relies on the public network to
transmit air traffic control information between individual airports.
Public telephone networks are also being increasingly relied upon for emergency
services. For example, the telephone has replaced fire alarm boxes as the
primary method for reporting fires. Emergency 911 service can be obtained from
personal or public pay phones. Telephones are also used to report medical
emergencies requiring emergency medical technicians, and burglaries and
domestic problems requiring responses from the police. Enhanced 911 service,
available in many locations, is even capable of automatically routing the
emergency call to a public service answering point, the facility in charge of
answering calls and dispatching appropriate services in the caller's area. The
system also searches phone company databases to determine and report the
caller's location and telephone number to the dispatcher.
RECENT NETWORK OUTAGES HAVE
RAISED CONCERNS AND CAUSED
ECONOMIC LOSSES
------------------------------------------------------------------ Chapter 4:1.1
While the public and private sectors are becoming more dependent on networks, a
growing number of major outages have raised concerns, triggered losses of
service, potentially risked lives, and affected the economy. Several of these
outages are highlighted below.
May 8, 1988: More than 500,000 business and residential customers lost
telephone service due to a fire at the Hinsdale, Illinois, central office.
During the following two weeks, approximately 3.5 million calls were disrupted.
Hospitals with centrex service in the affected area could not make calls from
one floor to another. Twenty percent of the departing flights from O'Hare
International Airport were canceled and flights from other airports around the
country had to be rescheduled. In a study of the Hinsdale outage, the
University of Minnesota concluded that the cost of network failures to airlines
could be between $2 and $3 million per hour and investment bankers could lose
up to $5 million per hour.
Jan. 4, 1991: Maintenance workers in a cable vault in New Jersey accidentally
cut an optical fiber transmission line that provided service to lower
Manhattan. Sixty percent of the calls into and out of the city were disrupted
for eight hours. The New York Mercantile Exchange and the Commodity Exchange
had to shut down operations. Voice and radar systems that are used to control
air traffic from facilities in New York, Washington, and Boston were disabled
for five hours.
Sept. 17, 1991: Through a power sharing arrangement with New York's
Consolidated Edison, AT&T agreed to use its own power when Consolidated
Edison's facilities were heavily loaded.\2 On this particularly warm day in
September, AT&T switched to its own power. Batteries designed to meet the
initial instantaneous power demand performed as intended. However, alarms that
were intended to inform technicians to start the facility's diesel generator
had been manually disabled. When the batteries discharged, all telephone
transmission systems in the facility shut down and voice and data
communications controlled by the facility failed. Voice and data
communications between the New York, Boston, and Washington Air Route Traffic
Control Centers stopped. Three New York area airports closed for several
hours. Flights destined for New York were either delayed or canceled. Air
traffic at Boston was severely disrupted and delays occurred nationwide. More
than 1,174 flights were canceled or delayed and approximately 85,000 passengers
were affected. The day after the phone outage, flight schedules were still
disrupted because aircraft were not at the right airports for the scheduled
morning flights.
Sept. 10, 1993: A road crew boring holes for highway road signs in Ohio cut a
high-capacity fiber-optic cable belonging to MCI.\3 The cable, which carries
most of the company's east-to-west traffic, was repaired in about seven hours.
However, millions of residential and business customers were unable to make
coast-to-coast calls during that period.
March 15, 1994: During the early morning hours a fire broke out in Pacific
Bell's Los Angeles central office known as the Madison Complex. Before
complete service was restored, almost 17 hours later, approximately 395,000
customers may have been affected and over 5 million calls were blocked.
Cable cuts, a source of major outages, occurred 160 times during the period
between March 1, 1992, and February 4, 1993, with 93 (58 percent) of them
caused by "dig-up" incidents, such as the one illustrated in figure 4.1. The
average time needed to restore service after a cable cut was 5.2 hours with a
maximum of 21.4 hours. The average time required to repair a fiber cable cut
was 14.2 hours with a maximum of 97.5 hours.
Figure 4.1: Fiber Optic Cable "Dig-up" Accident
Source: AT&T Technology Magazine.
On February 13, 1992, the FCC instituted mandatory outage reporting
requirements for outages that affect more than 30,000 customers for durations
lasting 30 minutes or longer. As of June 1994, more than 314 outages were
reported. The calculation of the cost of an outage is difficult because of the
variety of users that could be affected.
--------------------
\2 Wall Street Journal, December 12, 1991.
\3 Wall Street Journal, September 13, 1993.
NEW TECHNOLOGIES, NETWORK GROWTH,
AND COMPLEXITY WILL LIKELY
INCREASE NETWORK VULNERABILITY
------------------------------------------------------------------ Chapter 4:1.2
The deployment of advanced technologies, such as intelligent network
architectures, common channel signaling, integrated services digital network,
broadband transport facilities, customer control, and user-programmability, is
increasing network complexity and vulnerability. The new technologies,
described in appendix III, are also allowing network designers to concentrate
more traffic into larger and fewer switches, and to rely on fewer higher
capacity fiber optic cables to transmit hundreds of thousands of telephone
calls. Failure of any of these high-capacity elements could be potentially
devastating.
As the information superhighway grows, the number of networks and service
providers is also expected to grow. Telecommunications consumers will
increasingly acquire services from combinations of suppliers' products, service
providers, and network providers. Increasing network complexity will make it
more difficult to isolate and correct problems.
THE GOVERNMENT AND INDUSTRY ARE
TAKING STEPS TO ADDRESS RELIABILITY
-------------------------------------------------------------------- Chapter 4:2
In 1991, the FCC, concerned about the spate of telephone network outages that
affected a large number of subscribers on both the east and west coasts,
established the Network Reliability Council. The council's goal was to bring
together leaders of the telecommunications industry, telecommunications experts
from academia, and consumer organizations, to explore and recommend measures
that would enhance network reliability. Members include the executive officers
of most of the major U.S. telephone companies, principal equipment suppliers,
long-distance companies, consumer organizations, corporate and federal user
representatives, and state regulatory agencies.
The council established a steering committee and seven focus groups to deal
with the key problem areas--signaling network systems, digital cross-connect
systems, fiber cable cuts, fire prevention, enhanced 911 service, power
systems, and switching systems (with a focus on software). The groups
formulated recommendations for developing and implementing countermeasures to
reduce the number of outages; monitoring the results; and modifying, as
necessary, the countermeasures. The commission is now looking at these
recommendations and considering regulations that would require the carriers and
equipment suppliers to implement them.
In 1994, the Network Reliability Council restructured and created four focus
groups. The first group will concentrate on network reliability; the second
will examine reliability issues arising from expanded interconnection of
networks; the third will study network technology and examine reliability
concerns related to providing telephone service through cable, satellites, and
wireless systems; and the fourth group will study the reliability of critical
services, including 911, Federal Aviation Administration, military, and
government.
The Alliance for Telecommunications Industry Solutions--a private sector
organization--was formed to promote the timely establishment of
telecommunications standards and operational guidelines. Its members include
representatives of local exchange carriers, interexchange carriers, enhanced
service providers, manufacturers, vendors, and end users who participate in a
number of sponsored committees.
The alliance also sponsors the Network Operations Forum, a group of
telecommunications industry access providers and customers who meet
periodically to identify national operations issues involving the installation,
testing, and maintenance of access services. In July 1991, the alliance began
focusing on the area of network reliability. One of the forum's subcommittees
has developed traffic management guidelines that provide network management
personnel with alternatives when emergencies occur. The forum also maintains
contact directories for use in emergency situations.
CONCLUSIONS
====================================================================== Chapter 5
While the information superhighway's development is expected to be arduous, a
grand vision of its capabilities is beginning to emerge among policymakers,
industry leaders, and public interest groups. Viewed as a global metanetwork
that will seamlessly and reliably link millions of users through broadband
terrestrial and satellite digital networks, it is hoped that the superhighway
will allow users to routinely receive and transmit large volumes of digital
information, and ensure equal access for service and network providers.
Achieving the grand vision will depend largely on how successfully industry and
government meet the key technical challenges of security and privacy,
interoperability, and reliability.
Security and privacy of databases and users' communications is a critical
issue. The superhighway will become an increasingly enticing target for
intruders with the technical expertise and resources to cause damage. Given
the complexity, size, and importance of the evolving superhighway, significant
effort will be needed to define, develop, test, and implement security
measures.
Interoperability among the thousands of networks, communications devices, and
services that will comprise the superhighway is also essential, but will be
difficult to achieve. The telecommunications industry is deploying, or plans
to deploy, a host of technologies and services that are based on ill-defined,
anticipatory, or competing standards. A coordinated approach will help reduce
the risk of the superhighway being fragmented into thousands of poorly
integrated networks providing a bewildering choice of incompatible services.
Because the proposed superhighway is intended to provide critical commercial
and personal services, its end-to-end reliability requirements will be very
high. The public and private sectors are already highly dependent on the
existing telecommunications infrastructure and networks that will be the
foundation of the superhighway. Outages on these networks have raised concerns
about achieving reliability.
Government and industry are beginning to recognize these challenges. The
administration's Information Infrastructure Task Force, working together with
the private sector, has formed committees and working groups charged with
addressing security and privacy, interoperability, and reliability issues. The
challenge remains for the major public and private players to work together to
resolve these issues. With effective cooperation, the promise of the
information superhighway can be attained.
INFORMATION INFRASTRUCTURE TASK FORCE
IS ADDRESSING SELECTED TECHNICAL ISSUES
===================================================================== Appendix I
The administration formed the Information Infrastructure Task Force (IITF) to
articulate and implement its vision for the information superhighway. The task
force includes high-level representatives of federal agencies that play a major
role in the development and application of information and telecommunications
technologies. Working together with the private sector, the participating
agencies plan to develop comprehensive technology, telecommunications, and
information policies and promote applications that best meet the needs of both
the agencies and the country. By helping build consensus on difficult policy
issues, the IITF is planning to enable agencies to make and implement policy
more quickly and effectively.
The Secretary of Commerce chairs the IITF, and much of the staff work and
administrative support for the task force is being done by Commerce's National
Telecommunications and Information Administration. The task force operates
under the aegis of the White House Office of Science and Technology Policy and
the National Economic Council. The administration has also established the
United States Advisory Council on the National Information Infrastructure to
facilitate private sector input to the IITF. The Secretary appointed 37
members to serve a two-year term on the advisory council. The council members
represent the many different stakeholders in the information superhighway,
including industry, labor, academic, public interest groups, and state and
local governments.
The task force is undertaking a wide-ranging examination of all issues relevant
to the development and growth of the information superhighway. The
Administration's Agenda for Action, released September 15, 1993, identified
nine specific principles and goals to guide government action:
promoting private sector investment,
extending the "universal service" concept to ensure that information resources
are available to all at affordable prices,
promoting technological innovation and new applications,
promoting seamless and interactive operation,
ensuring information security and network reliability,
improving management of the radio frequency spectrum,
protecting intellectual property rights,
coordinating with other levels of government and with other nations, and
providing access to government information and improving government
procurement.
To carry out its responsibilities, the IITF established three
committees--Telecommunications Policy, Information Policy, and Applications and
Technology. The Telecommunications Policy Committee is responsible for
formulating a consistent administration position on key telecommunications
issues. The committee has established the following four working groups:
The universal service working group works to ensure that all Americans have
access to and can enjoy the benefits of the information superhighway.
The network reliability and vulnerability working group works to (1) ensure
that the superhighway will provide protection for all users from catastrophic
failure of the network, along with mechanisms for recovery from threats ranging
from natural disasters to overt attacks; and (2) define and monitor national
security and emergency preparedness requirements.
The international telecommunications working group examines international
telecommunications issues. This working group is subdivided into five
subworking groups that are addressing:
the participation of foreign governments/foreign corporations in the
superhighway and the use of the superhighway to open overseas markets,
the effects of current law on setting policy, and legislative efforts to change
the law,
the federal government's controls of technology exports,
U.S. participation in international organizations and standards-setting
bodies, and
international use of research networks.
The legislative drafting task force is to formulate the administration's
telecommunications legislative reform initiatives.
The Information Policy Committee has five working groups that are addressing
critical information policy issues:
The intellectual property rights working group is to develop proposals for
protecting copyrights and other intellectual property rights in an electronic
world.
The privacy working group is to develop proposals to protect individual
privacy.
The government information working group is to focus on ways to promote
dissemination of government data in electronic form.
The Freedom of Information Act legislation working group is to define public
access rights to government electronic records.
The scientific and technical information group is to focus on ways to manage
technical and scientific information.
The Committee on Applications and Technology coordinates the administration's
efforts to develop, demonstrate, and promote applications of information
technology in manufacturing, education, health care, government services,
libraries, environmental monitoring, electronic commerce, and other
applications. It has three working groups:
The government information technology services working group coordinates
efforts to improve the application of information technology by federal
agencies.
The technology policy working group addresses cross-cutting technology issues
related to interoperability and scalability of new telecommunications and
information services.
The health information and applications working group coordinates efforts that
affect use of the superhighway for health care.
The IITF has also established the NII Security Issues Forum to coordinate
security efforts across the committees and working groups of the IITF.
DESCRIPTION OF EXISTING NETWORK
TECHNOLOGIES
==================================================================== Appendix II
The following provides a brief overview of the three major types of
communication networks that comprise the existing communication
infrastructure--the wire-based voice and data telephone networks; the
cable-based video networks; and the wireless, voice, data, and video networks.
THE TELEPHONE NETWORKS
------------------------------------------------------------------ Appendix II:1
The telephone system is the world's largest switched distributed network
providing point-to-point voice, fax, data, and videoconferencing services to
hundreds of millions of subscribers. It is also, at first glance, the primary
foundation for the information superhighway. It is ubiquitous, highly
interoperable, and reliable. It is capable of handling millions of
simultaneous calls, and it provides accurate usage tracking and billing. In
the U.S., voice, data, and videoconferencing services are provided by the local
exchange carriers (local telephone companies) serving the local access and
transport areas, and by the interexchange carriers (long distance carriers)
providing long distance and international dialing services through their long
distance networks.\1 Although the industry is rapidly introducing advanced
digital communication technologies, the telephone network continues to be
dependent on analog transmission.\2
Much of today's telephone service is based on two analog-oriented transmission
technologies--the analog voice frequency (VF) systems and the digital T-carrier
system. The VF system supports voice transmission over a pair of copper
wires--also known as the local loop--connecting millions of residential and
business subscribers with the local telephone company's central offices. The
T-carrier system plays a major role in the first step in the transition from
analog to digital capabilities. One of the fastest growing segments of
services offered by the local telephone companies and the long distance
carriers, the system can provide transmission speeds up to 274.176 Mbps. The
basic building block of the T-carrier technology is a single VF voice channel
digitized into a 64 Kbps data stream; a T-1 line carries 24 digitized voice
channels, an aggregate of 1.544 Mbps. The T-carrier digital hierarchy allows
T-1 lines to be combined to provide transmission rates of up to 274.176 Mbps.
The telephone network's capabilities are unevenly distributed. Most of the
high-capacity fiber optic lines capable of carrying interactive video and other
bandwidth-intensive applications are either part of the long distance or the
local telephone area interoffice networks, or are used by the telephone
companies to provide private voice, data, and videoconferencing services to
business, government, and institutions. The bandwidth available to residential
subscribers is effectively constrained by the limited transmission capacity of
the copper wire linking the local telephone company's central office with the
subscriber's instrument, and the lack of subscriber's equipment capable of
providing broadband services. Similarly, although the local telephone
companies generally use digital switches to route telephone calls, in most
cases the calls are converted back to analog format for transmission to
individual subscribers. The basic architecture of a typical telephone network
is shown in figure II.1.
Figure II.1: A Typical Local
Telephone Network
(See figure in printed edition.)
Source: Adapted from the "Hybridizing the Local Loop," Craig J.
Burnet, IEEE Spectrum, June 1994.
--------------------
\1 The local telephone companies, created in the wake of the breakup of AT&T,
include 22 Bell Operating Companies organized into seven regional Bell holding
companies--Pacific Telesis, US West, Ameritech, Southwestern Bell, BellSouth,
Bell Atlantic, and NYNEX. Many local area and transport areas are also served
by independent telephone companies. The major long distance carriers include
AT&T, MCI, U.S. Sprint, Advanced Telecommunications Corporation, and Wiltel.
\2 During the 1980s, the telephone service providers replaced most of their
older electromechanical switches with analog or digital computer-driven
switches.
CABLE TELEVISION NETWORK
---------------------------------------------------------------- Appendix II:1.1
The nation's cable television network links thousands of cable systems with
millions of subscribers via broadband coaxial cable.\3 This web of coaxial
cables is, in many respects, a counterpart of the local loop linking telephone
subscribers with the local telephone companies. However, there are
considerable differences between the transmission technologies and network
architectures deployed in the telephone and the cable systems. The telephone
system is based on a switched, distributed network architecture, and uses
standard switching and transmission protocols capable of supporting global,
narrowband, two-way, point-to-point communications. The cable systems, on the
other hand, are based on a tree-and-branch network architecture and proprietary
transmission protocols designed to support one-way broadband analog
transmission with little or no provision for �upstream� communications. The
basic architecture of a typical cable system is shown in figure II.2.
Figure II.2: A Typical Cable System
Architecture
(See figure in printed edition.)
--------------------
\3 During the last decade, the cable television industry experienced
considerable growth, from 4,225 systems serving 17.7 million subscribers in
1980, to 11,075 cable systems serving over 57 million subscribers. Today,
cable service--or ready access to the service provider's coaxial cable--is
available to over 96 percent of the nation's homes.
WIRELESS NETWORKS
---------------------------------------------------------------- Appendix II:1.2
Wireless networks are an important element of the communications
infrastructure. These systems--including cellular and space-based systems and
networks--are providing users with an unprecedented degree of mobility and
flexibility. The cellular and satellite networks have advantages over
terrestrial networks because they are potentially accessible from any point on
the globe without the cost of installing wire or a cable. The current analog
cellular services were developed in the early 1970s to alleviate growing radio
frequency spectrum congestion and to overcome the limited capacity of the early
mobile radio systems. In the cellular systems, this is accomplished by
dividing a large geographic service area into discrete regions--or cells--each
of which is served by a low-power base station transmitting to and receiving
from mobile telephones within its area. The use of low-powered transmitters
operating on short-wavelengths allows the cellular systems to efficiently
exploit the available radio spectrum by "reusing" the assigned radio
frequencies throughout the service area.\4 However, the analog cellular systems
have not fulfilled their early promise. In many large metropolitan markets,
the systems are saturated and will be slowly supplemented, and eventually
replaced, with digital systems.\5 The architecture of a typical cellular system
is shown in figure II.3.
Figure II.3: A Typical Cellular
System Architecture
(See figure in printed edition.)
Satellite networks have advantages over terrestrial networks because they are
accessible from any spot on the globe; can provide broadband digital services,
including voice, data, and video, to many points without the cost of acquiring
right-of-way and cable installation; and can add receiving and transmitting
sites without significant additional costs. Commercially available since 1965,
communications satellites are a critical part of the global communications
infrastructure. Today, there are about 150 communications satellites in
geosynchronous orbit (GEO) providing a wide range of services, including
broadcast video and overseas telephone links.\6
In general, GEO satellites are designed to broadcast a wide beam to ensure the
coverage of a large geographic area. Although such a large broadcast
"footprint" allows only three GEO satellites to provide nearly global coverage,
the network's receiving stations require large antennas to capture the
relatively weak signal.
In the 1980s, industry introduced a new class of satellites using a narrow beam
to focus the transmitted energy on a small geographic areas. Known as very
small aperture terminal (VSAT) satellites, the new breed of satellites use
small ground antennas to provide low data rate point-to-point network services.
VSAT networks are being increasingly used by large corporations to link
hundreds of motel/hotel or retail sites. Figure II.4 shows a typical GEO
broadcast and VSAT satellite system based on a hub and spoke relay
configuration. Because this configuration does not allow direct
terminal-satellite-terminal relays, all communications must be routed through
the hub terminal.
Figure II.4: Broadcast and VSAT
Satellites
(See figure in printed edition.)
--------------------
\4 In the U.S. and in several other countries, the analog cellular systems are
based on the Advanced Mobile Phone Services standard. This standard provides
416 voice channels and employs a seven-cell frequency reuse pattern.
\5 The FCC requires that any new digital cellular system be fully compatible
with the current analog system. The new hand-held mobile units will be capable
of either analog or digital operation.
\6 GEO satellites are placed in a high circular orbit 22,300 miles above the
equator. Because GEO satellites rotate with the Earth, they appear to be
stationary.
DESCRIPTION OF ADVANCED TECHNOLOGIES
=================================================================== Appendix III
The communications industry is beginning to introduce several new and
innovative technologies that will allow the delivery of many of the advanced
services and capabilities of the information superhighway. These technologies
include
narrowband ISDN,
advanced signaling and intelligent networks,
B-ISDN,
personal communications networks, and
broadband in the local loop.
THE NARROWBAND ISDN
----------------------------------------------------------------- Appendix III:1
One of the emerging technologies that will be key to the future superhighway is
the narrowband ISDN. Deployment of this technology is the first step in the
conversion from the existing networks to a fully digital network. ISDN is an
end-to-end digital network that is evolving from the existing telephone
network. It is already providing some users with direct access to digital
transmissions--at speeds ranging from 144,000 bits per second (144 Kbps) to
1.544 Mbps--capable of handling many different forms and types of information,
including conventional analog voice, digital voice, and packet data.
Because of poorly defined standards, the early implementations of ISDN were
plagued with interoperability problems. In an effort to effectively manage the
integration of the ISDN technology with the public switched networks, the
industry has adopted a set of standards known as the National ISDN. National
ISDN will include advance signaling capabilities, as well as a wide range of
digital services.
Telecommuting or work-at-home is one area where the benefits of ISDN service
can be readily identified. Currently, an employee working at home may have to
install additional telephone lines to handle computer and fax communications.
Using ISDN, the telecommuter can communicate--over a single line--with the
employer's local area network, while simultaneously carrying on a telephone
conversation with a colleague and receiving a fax from the employer's office.
Similarly, as shown in figure III.1, a large business or institutional ISDN
customer can use ISDN to consolidate voice, data, and videoconferencing
services.
Figure III.1: ISDN Architecture
(See figure in printed edition.)
Source: Adapted from A Guide to New Technologies and Services, Bellcore, 1993;
figure 4-1, pp. 4-7.
ADVANCED SIGNALING AND INTELLIGENT
NETWORKS
----------------------------------------------------------------- Appendix III:2
In order to offer new services and advanced capabilities, such as 800 number
and ISDN services, the telephone industry is deploying common channel signaling
networks. These networks are based on the Signaling System 7 (SS7) protocol.
An SS7 network is a packet-switched communications network that transports call
control and signaling messages on a dedicated high-speed data network separate
from the voice or data communications networks. The SS7 provides capabilities
critical to the development of advanced intelligent networks (AIN). A
programmable AIN network provides the capability for network switches to
interrogate remote processors, databases, and mobile communications devices.
The network intelligence resides in on-line, real-time databases, rather than
in every switch, and is accessed through the SS7 signaling system. Such
intelligent networks allow greater customer control, provide the tools for the
creation of virtual private networks, increase competition by allowing
competing carriers to use the AIN capabilities to offer custom services, and
provide the mechanisms for alternative call destination routing required by the
emerging personal communications services (PCS).\1
Figure III.2 shows a simplified view of an AIN architecture.
Figure III.2: AIN Architecture
(See figure in printed edition.)
Source: Adapted from A Guide to New Technologies and Services, Bellcore, 1993;
figure 1-1, pp. 1-5.
--------------------
\1 PCS is a new type of service designed to support hand-held personal voice
and data communications terminals. Mobile PCS users are expected to be able to
receive services such as high-quality voice, data, facsimile, and video at any
terminal anywhere the user has directed his or her calls.
B-ISDN TECHNOLOGIES
----------------------------------------------------------------- Appendix III:3
The B-ISDN technology is a dramatic departure both from the existing digital
infrastructure and the narrowband ISDN concept. Because it will provide
transmission rates up to 2,488 Mbps, B-ISDN will not be able to use the
existing digital infrastructure, but will largely rely on the Asynchronous
Transfer Mode (ATM)/Synchronous Optical Network (SONET) optical fiber networks.
SONET, an international standard for optical carrier networks, provides a
variety of transmission rates in multiples of
51.84 Mbps, with currently deployed optical circuits operating between
156 to 622 Mbps, and with future circuits expected to operate at up to 2,488
Mbps. SONET will support B-ISDN using the ATM standard. While SONET is one of
the transmission technologies that provides the high-speed transmission system
required by the information superhighway, ATM will allow users to transmit a
rich mix of data during a single transmission session. Figure III.3 provides
an overview of the B-ISDN architecture.
Figure III.3: B-ISDN Architecture
(See figure in printed edition.)
Source: Adapted from A Guide to New Technologies and Services, Bellcore, 1993;
figure 2-6, pp. 2-11.
Much remains to be done to develop a global integrated B-ISDN network.
Although the local and long distance telephone companies are beginning to
deploy ATM/SONET networks, ATM standards are continuing to evolve. For
example, several standards, including service quality, transmission routing,
and encryption standards, have not yet been defined. The Advanced Research
Projects Agency and the National Science Foundation, in coordination with
industry, are actively pursuing investigations focused on the development of
ATM standards and network management tools. These two agencies established
five gigabit network research testbeds focused on ATM network technology,
alternative network architectures, and applications. In addition, the Advanced
Research Projects Agency is evaluating the best commercial prototypes of
ATM/SONET technology and related applications, including ATM satellite
connections and the encryption of gigabit data streams.
PERSONAL COMMUNICATIONS NETWORKS
----------------------------------------------------------------- Appendix III:4
Some observers believe that we are moving toward a ubiquitous, tetherless
global metanetwork composed of cellular and satellite communications systems
supplemented by wire-based ground networks. Personal communications networks
(PCN) and the related personal communications services (PCS) are expected to be
an important part of this tetherless metanetwork. PCNs are based on a concept
of tetherless digital communications systems providing mobile users with
worldwide connectivity. Unlike the station-to-station connectivity provided by
the existing telephone systems, PCNs will provide person-to-person access using
a national--and potentially worldwide--personal numbering concept.
Digital wireless communications, cellular systems, and the AIN capabilities of
the evolving B-ISDN networks are expected to play a crucial role in the
development of PCNs. Initially, PCNs will include a diverse mix of analog and
digital technologies and services--cellular systems, mobile satellite systems,
paging, and local area networks--based on radio access technology and
interfaced with the wire-based public networks. It is expected that a
full-scale PCN will deploy a combination of technologies, mostly because the
terrestrial wire and cellular networks will not provide worldwide connectivity,
particularly to users in remote areas. To achieve this objective, the
terrestrial cellular systems may be complemented by space-based cellular type
services.
There are two basic approaches to space-based PCNs. One uses satellites in
high geosynchronous earth orbit (GEO), while the other relies on a
constellation of low-earth orbit (LEO) satellites. The GEO systems, being in
higher orbit, require more power at both the transmitter and the receiver than
the LEOs, but provide more earth coverage with fewer spacecraft. On the other
hand, LEO systems, while cheaper on a unit-basis, require far more satellites
to provide earth coverage. In general, most of the recently proposed
space-based PCNs are focused on LEO systems, including Motorola's Iridium
system (77 satellites), TRW's Odyssey system (12 satellites), Leosat's system
(18 satellites), and the recently announced network of 840 satellites proposed
by the Teledesic Corp. Figure III.4 show a typical LEO satellite network.
Figure III.4: Low Earth Orbit
Satellite System
(See figure in printed edition.)
BROADBAND IN THE LOCAL LOOP
----------------------------------------------------------------- Appendix III:5
While industry is upgrading the transport layer and laying thousands of miles
of optical fiber, the on-ramps that will link the high-speed portions of the
national information infrastructure with homes, business, and institutions
continue to form a bottleneck to high-speed information flow. In the near
term, the primary challenge will be to provide broadband digital services over
the existing plant--the hundreds of thousands of miles of copper wire and
coaxial cable--although ultimately it may be preferable to provide fiber optics
to each residence. The replacement cost for this �last mile� of the
superhighway--linking the broadband backbone with residences, business, and
institutions--continues to be high, not only because there is so much copper
wire and coaxial cable to be replaced, but also because of the need for special
equipment to process the optical signal on the customer's premises.
The telephone and cable companies are adopting a mix of technologies and
strategies to cope with the bottleneck in the local loop--the portion of the
telephone communication circuit connecting individual subscribers with the
telephone company's central office. For the telephone companies, the most
promising approaches are the asymmetrical digital subscriber line and the
fiber-to-the-curb architectures. The asymmetrical digital subscriber line
allows telephone companies to use a single copper wire to simultaneously
transmit video and telephone signals by increasing the transmission speed from
64 Kbps to 1.5 Mbps while providing an upstream channel between 16 to 384 Kbps.
The fiber-to-the-curb architecture provides high-capacity switched digital
network services to optical network units serving multiple residences. Optical
network units house the necessary equipment to convert the optical signals to
electrical impulses and distribute them to individual homes over a copper wire
or coaxial cable.
Most of the newer or rebuilt cable systems also use a hybrid fiber
optics/coaxial cable architecture, commonly known as fiber trunk feeder. This
hybrid fiber optics/coaxial cable architecture is capable of supporting all
digital, fully switched ATM/SONET services. Figure III.5 highlights two
fiber-to-the-curb architectures that may be used by the telephone and cable
industries to deliver broadband services to subscribers.
Figure III.5: Broadband in the
Local Loop
(See figure in printed edition.)
ENSURING THE PORTABILITY OF TELEPHONE
NUMBERS POSES A CHALLENGE
==================================================================== Appendix IV
The ability of the public networks to efficiently route and deliver electronic
communications is heavily dependent on the efficient allocation and use of a
limited resource--the pool of available ten-digit telephone numbers. In recent
years, the proliferation of telecommunications services and providers has
placed increasing demands on this resource. More importantly, new
requirements, such as demands for (1) personal mobility, whereby communications
services are provided to individuals, rather than to fixed geographic locations
(for example geographic mobility), and (2) number portability, whereby
customers are able to change service features and providers quickly without
needing to change their telephone number, will significantly alter the way we
manage the numbering resources.
The first demand--the provision of services to individuals rather than fixed
geographic locations--will be largely satisfied by emerging PCSs. PCSs will
exploit the capabilities of AIN and nongeographic telephone numbers to provide
wireless or land-line based services to "roaming" individuals. The second
demand--the assignment of a permanent "personal" telephone number to
individuals--will require the development of national or regional databases
containing the personal numbers and customer service profiles. Although there
are no insurmountable technical barriers to number portability, industry's
experience with the development of full portability for the 800 number services
indicates that it will be a lengthy and arduous process.\1
--------------------
\1 It took almost 7 years for industry to implement full portability for 800
service.
THE NORTH AMERICAN NUMBERING PLAN
GUIDES THE MANAGEMENT OF NUMBERING
RESOURCES
------------------------------------------------------------------ Appendix IV:1
The basic telephone numbering scheme, known as the North American Numbering
Plan (NANP), was developed the Bell System. In 1984, following the AT&T
divestiture, the numbering plan functions performed by AT&T were transferred to
Bell Communications Research (Bellcore). Since that time, Bellcore has served
as the NANP administrator. Under NANP, each telephone within the World Zone
1\2 can be reached by dialing a unique ten-digit number generally composed of
three parts--a three-digit geographic area code, a three-digit secondary code,
and a four-digit "station" or "line" code.
However, under the current format, there are only 160 possible area codes.
These represent the number of combinations available when the first digit
cannot be zero or one, and the second digit is always zero or one. Sixteen of
the codes have a unique format: eight have a double "0" ("N00" codes) and
eight have a double "1" ("N11" codes). The N00 codes are called Service Access
Codes (SAC).\3 The most widely recognized SACs are the 800 and 900 codes. The
N11 codes are known as "service codes" and are set aside for special functions,
the most widely used being the 911 emergency code. All of the remaining 144
codes are assigned and it has been long expected that the present stock of
codes would be exhausted sometime in the 1990s.
A numbering relief plan, scheduled to be implemented in January 1995, will
expand the number of potential codes from 160 to 800. This expansion will be
accomplished by allowing the second digit of the area code to include the
digits "2" through "9" in addition to "1" and "0". For example, area code 334
is scheduled to be placed in service in northern Alabama on January 15, 1995.
The addition of 640 new codes will not only significantly increase the
numbering resource, but may also provide additional codes for nongeographic
assignment such as the "personal" numbers needed for PCS users. Because the
new codes will not be available until 1995, carriers anxious to offer PCS asked
Bellcore for the assignment of one of the four nongeographic codes (500 SAC)
for PCS. The carriers plan to offer PCS that includes personal mobility,
terminal mobility, and service profile services, but not, at least initially,
number portability. In essence, PCS users would have to be issued a new
telephone number every time they changed a PCS provider.
--------------------
\2 The World Zone 1 includes the United States, Canada, Bermuda, and most of
the Caribbean. It provides a uniform dialing scheme applicable in 18
countries, and serves more than a thousand local exchange carriers, several
hundred long distance carriers, and over one hundred million customers.
International calls to countries not included in the NANP require the dialing
of country codes; thus telephone numbers can differ in length from country to
country.
\3 Three SACs (700, 800, and 900) are currently in use through World Zone 1;
one (600) is assigned to the Canadian government, while the 500 SAC has been
assigned for roaming PCS.
PORTABILITY ISSUES REMAIN UNRESOLVED
------------------------------------------------------------------ Appendix IV:2
In June 1993, Bellcore informed the FCC that it had decided, absent
instructions to the contrary, to proceed with the assignment of 500 SAC for PCS
service to carriers that had expressed an urgent need for these assignments.
In response to Bellcore's notification, the FCC requested public comments on
the proposed assignment of the 500 SAC for PCS, and directed Bellcore to delay
the assignments until it had a chance to consider the comments. At the same
time, FCC asked Bellcore to submit, within 30 days, a detailed proposal for
achieving 500 number portability. In response, Bellcore noted that there were
many ways to achieve number portability, but did not offer a concrete proposal.
An industry workgroup is addressing the issue of PCS number portability.
Bellcore began assigining numbering resources within the 500 SAC for roaming
services after the FCC considered the comments on the issue and gave its
approval in May 1994. Bellcore also notified the FCC that because of the many
changes in the telecommunications environment which have resulted in increased
controversy regarding numbering, Bellcore and its owners believed that it was
time to relinquish Bellcore's voluntary administration of the NANP.
The FCC has yet to take final action in finding a replacement for Bellcore or
to act on the 500 SAC portability issues. According to the United States
Telephone Association, it appears unlikely that the initial PCS services will
provide number portability. Full national number portability may not be
available for years, given that the design and deployment of a database
architecture for the 500 SAC will take considerable time.
MAJOR CONTRIBUTORS TO THIS REPORT
===================================================================== Appendix V
ACCOUNTING AND INFORMATION
MANAGEMENT DIVISION, WASHINGTON D.C.
------------------------------------------------------------------- Appendix V:1
Rona B. Stillman, Chief Scientist for Computers and Communications
Ronald W. Beers, Assistant Director
Mirko J. Dolak, Evaluator-in-Charge
John P. Rehberger, Staff Evaluator
Shane D. Hartzler, Reports Analyst
Susan B. Willson, Secretary
OFFICE OF GENERAL COUNSEL
------------------------------------------------------------------- Appendix V:2
John A. Carter, Senior Attorney
RESOURCES, COMMUNITY, AND ECONOMIC
DEVELOPMENT DIVISION
------------------------------------------------------------------- Appendix V:3
Paul J. O'Neill, Assistant Director
Edmond E. Menoche, Senior Evaluator
BOSTON REGIONAL OFFICE
------------------------------------------------------------------- Appendix V:4
Bruce Holmes, Assistant Director
GLOSSARY
====================================================================== Chapter 1
The definitions in this glossary are drawn from several sources, including the
Computer Dictionary: The Comprehensive Standards for Business, School,
Library, and Home, Microsoft Press, 1991, Washington, D.C.; The McGraw-Hill
Telecommunications Factbook, McGraw-Hill, New York, 1993; The New IEEE Standard
Dictionary of Electrical and Electronic Terms, The Institute of Electrical and
Electronic Engineers, New York, 1993; and the Auerbach Data Communication
Management, Auerbach Publishers, Pennsauken, New Jersey, 1994.
ADDRESS
------------------------------------------------------------------ Chapter 1:0.1
A sequence of bits or characters that identifies the destination and the source
of a transmission.
ADVANCED INTELLIGENT NETWORK
------------------------------------------------------------------ Chapter 1:0.2
An evolving architecture that allows rapid creation and modification of
telecommunications services.
AGILE MANUFACTURING
------------------------------------------------------------------ Chapter 1:0.3
An approach to industrial production that allows a manufacturer to rapidly
respond to market demand by reducing the time it takes to design and
manufacture a product. Also known as rapid response or demand activated
manufacturing.
AMPLITUDE
------------------------------------------------------------------ Chapter 1:0.4
A relative magnitude of a signal.
ANALOG
------------------------------------------------------------------ Chapter 1:0.5
A term applied to any device, usually electronic, that represents values by a
continuously variable physical property, such as voltage in an electronic
circuit. An analog device can represent an infinite number of values within
the range the device can handle. In contrast, digital representation maps
values onto discrete numbers, limiting the possible range of values to the
resolution of the digital device.
ANALOG SIGNAL
------------------------------------------------------------------ Chapter 1:0.6
A continuous electrical signal whose amplitude varies in direct correlation
with the original input.
ARCHITECTURE
------------------------------------------------------------------ Chapter 1:0.7
A general term referring to the structure of all or part of a computer system.
The term also covers the design of system software, such as the operating
system, as well as refers to the combination of hardware and basic software
that links the machines on a computer network. Computer architecture refers to
an entire structure and to the details needed to make it functional. Thus,
computer architecture covers computer systems, chips, circuits, and system
programs, but typically does not cover applications, which are required to
perform a task but not to make the system run.
ASYNCHRONOUS OPERATION
------------------------------------------------------------------ Chapter 1:0.8
Generally, an operation that proceeds independently of any timing mechanism,
such as a clock. In communications, for example, two modems communicating
asynchronously rely upon each one sending the other start and stop signals in
order to pace the exchange of information.
ASYNCHRONOUS TRANSFER MODE
------------------------------------------------------------------ Chapter 1:0.9
A fast-packet technology that was developed for use in area networks using
fixed-length cells. Current ATM standards allow it to scale from speeds of 155
Mbps to 622 Mbps over fiber networks. ATM appears to be the best alternative
for multimedia applications where data are mixed with voice, images, or
full-motion video.
BANDWIDTH
----------------------------------------------------------------- Chapter 1:0.10
In communications, the difference between the highest and lowest frequencies in
a given range. For example, a telephone accommodates a bandwidth of 3000 hertz
(Hz), the difference between the lowest (300 Hz) and highest (3300 Hz)
frequencies it can carry. In computer networks, greater bandwidth indicates
faster data-transfer capabilities.
BASIC RATE INTERFACE
----------------------------------------------------------------- Chapter 1:0.11
Transmission rates for the integrated service digital network. Basic rate
interface consists of two 64 Kbps channels and one 16 Kbps channel
packet-switched data channel used for signaling and packet data transmission
functions.
BIT
----------------------------------------------------------------- Chapter 1:0.12
Short for "binary digit"; either 1 or 0 in the binary number system. In
processing and storage, a bit is the smallest unit of information handled by a
computer and is represented physically by an element such as a single pulse
sent through a circuit or a small spot on a magnetic disk capable of storing
either a 1 or a 0. Considered singly, bits convey little information a human
would consider meaningful. In groups of eight, however, bits become the
familiar bytes used to represent all types of information, including the
letters of the alphabet and the digits.
BROADBAND NETWORK
----------------------------------------------------------------- Chapter 1:0.13
A type of local area network on which transmissions travel as radio-frequency
signals over separate inbound and outbound channels. Stations on a broadband
network are connected by coaxial or fiber-optic cable. The cable itself can be
made to carry data, voice, and video simultaneously over multiple transmission
channels. This complex transmission is accomplished by the technique called
frequency-division multiplexing, in which individual channels are separated by
frequency and buffered from one another by guard bands of frequencies that are
not used for transmission. A broadband network is capable of high-speed
operation (20 megabits or more), but it is more expensive than a baseband
network and can be difficult to install. Such a network is based on the same
technology as is used by cable television. Broadband transmission is sometimes
called wideband transmission.
CAPSTONE CHIP
----------------------------------------------------------------- Chapter 1:0.14
A data security chip. The Capstone chip, also known as MYK-80, incorporates
NSA's Skipjack, key exchange algorithms, and the NIST digital signature and
secure hash algorithms.
CELL
----------------------------------------------------------------- Chapter 1:0.15
In cellular systems, the smallest geographic area defined for mobile
communications systems.
CELLULAR SYSTEMS
----------------------------------------------------------------- Chapter 1:0.16
Mobile telephony systems employing hexagonal geographic areas, or cells, with
group frequencies allocated to each cell. Typically, seven cells make a block,
and no adjacent cell uses the same set of frequencies.
CIPHERTEXT
----------------------------------------------------------------- Chapter 1:0.17
The encrypted form of a plaintext message or data.
CIRCUIT SWITCHING
----------------------------------------------------------------- Chapter 1:0.18
A method of opening communications lines, as through the telephone system,
creating a physical link between the initiating and receiving parties. In
circuit switching, the connection is made at a switching center, which
physically connects the two parties and maintains an open line between them for
as long as needed. Circuit switching is typically used in modem communications
on the dial-up telephone network, and it is also used on a smaller scale in
privately maintained communications networks.
CLIPPER CHIP
----------------------------------------------------------------- Chapter 1:0.19
A microcircuit that contains a classified secret-key encryption algorithm known
as Skipjack. The Clipper chip family, manufactured by Mykotronx, Inc.,
includes three prototypes chips--the MYK-78E, MYK-78T, and MYK-77. MYK-78E and
MYK-78T are designed for wirebased digital telephony. MYK-77 is designed for
use in digital radios operating at low data rates. Also see Capstone Chip.
COAXIAL CABLE
----------------------------------------------------------------- Chapter 1:0.20
Often referred to as coax or coax cable. A cable that consists of two
conductors, a center wire inside a cylindrical shield that is grounded. The
shield is typically made of braided wire and is insulated from the center wire.
The shield minimizes electrical and radio-frequency interference; signals in a
coaxial cable do not affect nearby components, and potential interference from
these components does not affect the signal carried on the cable.
CODE DIVISION MULTIPLE ACCESS
----------------------------------------------------------------- Chapter 1:0.21
A cellular digital standard that deploys frequency hopping--rapid change of
frequency--with the carrier frequency continually shifted through a wideband
channel.
COMMON CHANNEL SIGNALING
----------------------------------------------------------------- Chapter 1:0.22
A method of carrying signaling and supervisory information between telephone
central offices in a separate, dedicated channel.
COMMUNICATIONS PROTOCOL
----------------------------------------------------------------- Chapter 1:0.23
A set of rules or standards designed to enable computers to connect with one
another and to exchange information with as little error as possible. The word
"protocol" is used, sometimes confusingly, in reference to a multitude of
standards affecting different aspects of communication. Some standards affect
hardware connections, while other standards govern data transmission. Still
other protocols govern file transfer, and others define the methods by which
messages are passed around the stations on a local area network. Taken as a
whole, these various and sometimes conflicting protocols represent attempts to
facilitate communication among computers of different makes and models.
COMPUTER NETWORK
----------------------------------------------------------------- Chapter 1:0.24
A group of computers and associated devices that are connected by
communications facilities. A network can involve permanent connections, such
as cables, or temporary connections made through telephone or other
communications links. A network can be as small as a local area network
consisting of a few computers, printers, and other devices, or it can consist
of many small and large computers distributed over a vast geographic area.
Small or large, a computer network exists to provide computer users with the
means of communicating and transferring information electronically. Some types
of communication are simple user-to-user messages; others, of the type known as
distributed processes, can involve several computers and the sharing of
workloads or cooperative efforts in performing a task.
CRYPTANALYSIS
----------------------------------------------------------------- Chapter 1:0.25
The process of converting encrypted messages into plaintext without knowledge
of the key employed in the encryption algorithm.
CRYPTOGRAPHY
----------------------------------------------------------------- Chapter 1:0.26
The transformation of ordinary text--or plaintext--and other data into coded
form by encryption and the transformation of the coded text or data back to
plaintext or data by decryption.
CRYPTOGRAPHIC ALGORITHM
----------------------------------------------------------------- Chapter 1:0.27
A mathematical procedure used for such purposes as encrypting and decrypting
messages and signing documents digitally.
CRYPTOGRAPHIC SYSTEM
----------------------------------------------------------------- Chapter 1:0.28
The hardware, software, documents, and associated techniques and processes that
together provide a means of encryption.
DATA ENCRYPTION STANDARD
----------------------------------------------------------------- Chapter 1:0.29
A NIST Federal Information Processing Standard and a commonly used secret-key
cryptographic algorithm for encrypting and decrypting data.
DIGITAL
----------------------------------------------------------------- Chapter 1:0.30
Related to digits or the way they are represented. In computing, digital is
virtually synonymous with binary because the computers familiar to most people
process information coded as combinations of binary digits, or bits--zeros and
ones. One bit can represent at most two values--0 or 1. Two bits can
represent up to 4 different values--00, 01, 11, and 10. Eight bits can
represent 256 values--00000000, 00000001, 00000011, and so on.
DIGITAL SIGNATURE
----------------------------------------------------------------- Chapter 1:0.31
A cryptographic method, provided by public-key cryptography, used by a
message's recipient or any third party to verify the identity of the message's
sender and the integrity of the message. A sender creates a digital signature
or a message by transforming the message with his or her private key. A
recipient, using the sender's public key, verifies the digital signature by
applying a corresponding transformation to the message and the signature.
DIGITAL SIGNATURE STANDARD
----------------------------------------------------------------- Chapter 1:0.32
A NIST Federal Information Processing Standard that supports digital signature.
ELECTRONIC SIGNATURE
----------------------------------------------------------------- Chapter 1:0.33
See digital signature.
ENCRYPTION
----------------------------------------------------------------- Chapter 1:0.34
The transformation of data into a form readable only by using the appropriate
key, held only by authorized parties. The key rearranges the data into its
original form by reversing the encryption.
ESCROW ENCRYPTION STANDARD
----------------------------------------------------------------- Chapter 1:0.35
A Federal Information Processing Standard specifying technology that provides a
mechanism for the secure escrow of encryption keys, which can be used to
intercept message only by government officials acting under proper legal
authorization. The standard relies on a key escrow chip, known as Clipper,
programmed with the classified Skipjack algorithm. Also see Clipper Chip,
Capstone Chip, Skipjack, key escrow system, private key, public key
cryptography.
FIBER-OPTICS
----------------------------------------------------------------- Chapter 1:0.36
A method of transmitting light beams along optical fibers. A light beam, such
as that produced in a laser, can be modulated to carry information. A single
fiber-optic channel can carry significantly more information than most other
means of information transmission. Optical fibers are thin strands of glass or
other transparent material.
FRAME RELAY
----------------------------------------------------------------- Chapter 1:0.37
A type of fast packet technology using variable length packets called frames.
By contrast, a cell relay system, such as ATM, transports user data in
fixed-sized cells.
GEOSYNCHRONOUS ORBIT
----------------------------------------------------------------- Chapter 1:0.38
The orbit of a satellite in which the speed and path are precisely timed to
position it 22,300 miles over a fixed location on Earth.
GIGA
----------------------------------------------------------------- Chapter 1:0.39
A prefix for one billion (10\9 ) times a specific unit.
GIGABYTE
----------------------------------------------------------------- Chapter 1:0.40
The precise meaning often varies with the context; strictly, a gigabyte is 1
billion bytes. In reference to computers, however, bytes are often expressed
in multiples of powers of two. Therefore, a gigabyte can also be either 1,000
megabytes or 1,024 megabytes, where a megabyte is considered to be 1,048,576
bytes.
GLOBAL SYSTEM FOR MOBILE
COMMUNICATIONS
----------------------------------------------------------------- Chapter 1:0.41
A European standard for digital cellular services.
HACKER
----------------------------------------------------------------- Chapter 1:0.42
A person who accesses or attempts to access a computer without authorization.
For the purpose of this report, the term hacker refers to an external threat of
unauthorized access to communications networks and related systems.
HASH FUNCTION
----------------------------------------------------------------- Chapter 1:0.43
A technique for computing a hash total. Hash total is an error-checking value
derived from the addition of a set of numbers taken from text or data. In
cryptography, the recipient may use the hash function to verify a message's
integrity by recalculating and verifying the hash total. If the two do not
match, the original information has been changed in some way.
HERTZ
----------------------------------------------------------------- Chapter 1:0.44
A unit of frequency equal to one cycle per second.
INFORMATION SUPERHIGHWAY
----------------------------------------------------------------- Chapter 1:0.45
A popular term for the emerging global broadband digital metanetwork. Also
known as the national information infrastructure, infobahn, or global grid.
INTERACTIVE
----------------------------------------------------------------- Chapter 1:0.46
Operating in a back-and-forth, often conversational manner, as when a user
enters a question or command and the system immediately responds.
Microcomputers are interactive machines; this interactivity is one of the
features that make them approachable and easy to use.
INTERNATIONAL DATA ENCRYPTION
ALGORITHM
----------------------------------------------------------------- Chapter 1:0.47
A block-encryption algorithm that operates on 64 bits of plaintext at a time.
Developed by James Massay and Xuejia Lai at ETH, a technical institute in
Zurich, the International Data Encryption Algorithm (IDEA) is perceived as a
potential replacement for Data Encryption Standard. Also see Pretty Good
Privacy.
INTERNET
----------------------------------------------------------------- Chapter 1:0.48
Abbreviation for "internetwork." In communications, a set of computer
networks--possibly dissimilar--joined together by means of gateways that handle
data transfer and the conversion of messages from the sending network to the
protocols used by the receiving network (with packets if necessary). When
capitalized, the term "Internet" refers to the collection of networks and
gateways that use the Transmission Control Protocol/Internet Protocol suite of
protocols.
INTEROPERABILITY
----------------------------------------------------------------- Chapter 1:0.49
The ability of two or more systems or components to exchange information and to
use the information that has been exchanged.
ISDN
----------------------------------------------------------------- Chapter 1:0.50
Abbreviation for "Integrated Services Digital Network"--a worldwide digital
communications network evolving from existing telephone services. The goal of
ISDN is to replace the current analog telephone system with totally digital
switching and transmission facilities capable of carrying data ranging from
voice to computer transmissions, music, and video. ISDN is built on two main
types of communications channels: a B channel, which carries data at a rate of
64 Kbps (kilobits per second), and a D channel, which carries control
information at either 16 or 64 Kbps. Computers and other devices are connected
to ISDN lines through simple, standardized interfaces. When fully implemented
(possibly around the turn of the century), ISDN is expected to provide users
with faster, more extensive communications services.
JAPANESE DIGITAL CELLULAR
----------------------------------------------------------------- Chapter 1:0.51
A Japanese standard for digital cellular services.
KEY
----------------------------------------------------------------- Chapter 1:0.52
A long stream of seemingly random bits used with cryptographic algorithms. The
keys must be known or guessed to forge a digital signature or decrypt an
encrypted message.
KEY ESCROW SYSTEM
----------------------------------------------------------------- Chapter 1:0.53
A mechanism for the secure escrow, and controlled release, of secret or private
encryption keys to law enforcement officials. Also see Escrow Encryption
Standard.
KILO
----------------------------------------------------------------- Chapter 1:0.54
A prefix for one thousand (10\3 ) times a specific unit.
LAST MILE
----------------------------------------------------------------- Chapter 1:0.55
A popular term for the last segment of the connection between a communication
provider and the customer. Also see local loop and on-ramps.
LOCAL AREA NETWORK
----------------------------------------------------------------- Chapter 1:0.56
A group of computers and other devices dispersed over a relatively limited area
and connected by a communications link that enables a device to interact with
any other on the network. Local area networks (LANs) commonly include
microcomputers and shared (often expensive) resources such as laser printers
and large hard disks. Most modern LANs can support a wide variety of computers
and other devices. Each device must use the proper physical and data-link
protocols for the particular LAN, and all devices that want to communicate with
each other on the LAN must use the same upper-level communications protocol.
Although single LANs are geographically limited (to a department or an office
building, for example), separate LANs can be connected to form larger networks.
Similar LANs are linked by bridges that act as transfer points between
networks; dissimilar LANs are linked by gateways, which both transfer data and
convert it according to the protocols used by the receiving network.
The devices on a LAN are known as nodes, and the nodes are connected by cables
through which messages are transmitted. Types of cables include twisted-pair
wiring, coaxial cable, or fiber-optic (light-transmitting) cable. Nodes on a
LAN can be wired together in any of three basic layouts, known as bus, ring,
and star. As implied by their names, a bus network is more or less linear, a
ring network forms a loop, and a star network radiates from a central hub. To
avoid potential collisions when two or more nodes attempt to transmit at the
same time, LANs use either contention and collision detection or token passing
to regulate traffic.
LOCAL LOOP
----------------------------------------------------------------- Chapter 1:0.57
A communication circuit connecting the telephone company central office with a
subscriber's instrument. Also see last mile and on-ramps.
MEGA
----------------------------------------------------------------- Chapter 1:0.58
Abbreviated M. A prefix meaning 1 million (10\6 ). In computing, which is
based on the binary (base-2) numbering system, mega has a literal value of
1,048,576, which is the power of 2 closest to one million.
MEGABIT
----------------------------------------------------------------- Chapter 1:0.59
Abbreviated Mb or Mbit. Usually, 1,048,576 bits; sometimes interpreted as 1
million bits.
MEGABYTE
----------------------------------------------------------------- Chapter 1:0.60
Abbreviated MB. Either 1 million bytes or 1,048,576 bytes.
METANETWORK
----------------------------------------------------------------- Chapter 1:0.61
A "super" network connecting many other networks. A network of networks.
MULTICAST
----------------------------------------------------------------- Chapter 1:0.62
A variant of broadcast, where information can be sent to selected recipients
instead of all subscribers of a particular communications system.
MULTIMEDIA
----------------------------------------------------------------- Chapter 1:0.63
A popular term for the integration of information in a single format, for
example an electronic document that may contain text, embedded voice, video, or
images.
NARROWBAND NETWORK
----------------------------------------------------------------- Chapter 1:0.64
A flexible, all purpose, two-way medium that supports transmission rates under
1.5 Mbps. Also see broadband network.
NATIONAL INFORMATION
INFRASTRUCTURE
----------------------------------------------------------------- Chapter 1:0.65
The administration's term for the information superhighway.
NETWORK ARCHITECTURE
----------------------------------------------------------------- Chapter 1:0.66
The underlying structure of a computer network, including hardware, functional
layers, interfaces, and protocols (rules) used to establish communications and
ensure the reliable transfer of information. Because a computer network is a
mixture of hardware and software, network architectures are designed to provide
both philosophical and physical standards for enabling computers and other
devices to handle the complexities of establishing communications links and
transferring information without conflict. Various network architectures
exist, among them the internationally accepted seven-layer open systems
interconnection model and International Business Machine (IBM) Systems Network
Architecture. Both the open systems interconnection model and the Systems
Network Architecture organize network functions in layers, each layer dedicated
to a particular aspect of communication or transmission and each requiring
protocols that define how functions are carried out. The ultimate objective of
these and other network architectures is the creation of communications
standards that will enable computers of many kinds to exchange information
freely.
NORTH AMERICAN DUAL-MODE CELLULAR
SYSTEM
----------------------------------------------------------------- Chapter 1:0.67
A North American standard for digital cellular services.
ON RAMP
----------------------------------------------------------------- Chapter 1:0.68
A popular term for a digital broadband connection linking a subscriber with the
information superhighway. Also see local loop and last mile.
OPERATING SYSTEM
----------------------------------------------------------------- Chapter 1:0.69
The software responsible for controlling the allocation and usage of hardware
resources such as memory, the central processing unit, disk space, and
peripheral devices.
OPTICAL FIBER
----------------------------------------------------------------- Chapter 1:0.70
A lightguide for electromagnetic waves traveling in the infrared and visible
light spectrum. An optical fiber consists of two different types of glass,
core and cladding, surrounded by a protective coating. The core is the
light-guiding region of the fiber, while the cladding ensures that the light
pulses remain within the core. One mile of fiber, capable of transmission
speeds of 2,500 Mbps (2.5 gigabits per second) weighs about 1/7 of a pound. A
copper cable with the same information-carrying capacity would weigh 33 tons.
PACKET
----------------------------------------------------------------- Chapter 1:0.71
In general usage, a unit of information transmitted as a whole from one device
to another on a network. In packet-switching networks, a packet is defined
more specifically as a transmission unit of fixed maximum size that consists of
binary digits representing both data and a header containing an identification
number, source and destination addresses, and, sometimes, error-control data.
PACKET SWITCHING
----------------------------------------------------------------- Chapter 1:0.72
A message-delivery technique in which small units of information (packets) are
relayed through stations in a computer network along the best route currently
available between the source and the destination. A packet-switching network
handles information in small units, breaking long messages into multiple
packets before routing. Although each packet may travel along a different
path, and the packets composing a message may arrive at different times or out
of sequence, the receiving computer reassembles the original message.
Packet-switching networks are considered to be fast and efficient. To manage
the tasks of routing traffic and assembling/disassembling packets, such
networks require some "intelligence" from the computers and software that
control delivery.
PERSONAL COMMUNICATIONS NETWORK
----------------------------------------------------------------- Chapter 1:0.73
Advanced cellular communications and the internetworking of both wire and
wireless networks that are expected to offer new communications services via
very small portable handsets. The network will rely on microcellular
technology--many low-power, small-coverage cells--and a common channel
signaling technology, to provide a wide variety of features in addition to the
basic two-way telephone service.
PLAINTEXT
----------------------------------------------------------------- Chapter 1:0.74
Plain, unencrypted text or data.
POINT OF PRESENCE
----------------------------------------------------------------- Chapter 1:0.75
A long distance carrier's network access facility located within the service
area of a local telephone company.
PRETTY GOOD PRIVACY
----------------------------------------------------------------- Chapter 1:0.76
A cryptographic software application for the protection of computer files and
electronic mail. It combines the convenience of the Rivest-Shamir-Adelman
public key algorithm with the speed of the secret-key IDEA algorithm, digital
signature, and key management. It was developed by Philip Zimmerman, and is
available globally as freeware from Internet sites or as commercial software.
PRIMARY RATE INTERFACE
----------------------------------------------------------------- Chapter 1:0.77
A transmission rate interface for the integrated service digital network. It
consists of 23 64 Kbps channels and one 64 Kbps channel used for signaling.
Six of the 64 Kbps channels can be combined into a single 384 Kbps channel, or
24 64 Kbps channels can be combined to form a single 1.536 Mbps channel. These
bundles can support applications requiring high data rates, such as video or
host-to-host bulk data transfers.
PRIVATE KEY
----------------------------------------------------------------- Chapter 1:0.78
The undisclosed key in a matched key pair--private key and public key--used in
public key cryptographic systems.
PRIVATE BRANCH EXCHANGE
----------------------------------------------------------------- Chapter 1:0.79
A private telephone exchange connected to the public telephone network.
PUBLIC KEY
----------------------------------------------------------------- Chapter 1:0.80
The key in a matched key pair--private key and public key--that is made public,
for example, posted in a public directory, for public key cryptography.
PUBLIC KEY CRYPTOGRAPHY
----------------------------------------------------------------- Chapter 1:0.81
Cryptography using two matched keys (or asymmetric cryptography) in which a
single private key is not shared by a pair of users. Instead, each user has a
key pair. Each key pair consists of a private key that is kept secret by the
user and a public key that is posted in a public directory. Public key
cryptography is used to perform (1) digital signature, (2) secure transmission
or exchange of secret keys, and/or (3) encryption and decryption.
REAL-TIME SYSTEM
----------------------------------------------------------------- Chapter 1:0.82
A computer and/or a software system that reacts to events before the events
become obsolete. For example, airline collision avoidance systems must process
radar input, detect a possible collision, and warn air traffic controllers or
pilots while they still have time to react.
RIVEST-SHAMIR-ADELMAN ALGORITHM
----------------------------------------------------------------- Chapter 1:0.83
A public key algorithm invented by Ronald L. Rivest, Adi Shamir, and Leonard
M. Adelman. The algorithm can be used to generate digital signatures, encrypt
messages, and provide key management for Data Encryption Standard and other
secret key algorithms.
SECRET KEY
----------------------------------------------------------------- Chapter 1:0.84
The single key that two or more parties share and keep secret for secret key
cryptography. Given secret key algorithms of equal strength, the approximate
difficulty of decrypting encrypted messages by brute force search can be
measured by the number of possible keys. For example, a key length of 56 bits
is over 65,000 times stronger or more resistant to attack than a key length of
40 bits.
SECRET KEY CRYPTOGRAPHY
----------------------------------------------------------------- Chapter 1:0.85
Cryptography based on a single key (or symmetric cryptography). It uses the
same secret key for encryption and decryption.
SIGNALING
----------------------------------------------------------------- Chapter 1:0.86
The process of generating and exchanging information between components of
telecommunications systems to establish, monitor, or release connections (call
handling functions) and to control related network and system operations and
functions.
SIGNALING SYSTEM 7
----------------------------------------------------------------- Chapter 1:0.87
An international common channel signaling system.
SKIPJACK
----------------------------------------------------------------- Chapter 1:0.88
A classified encryption algorithm. Skipjack provides high-speed encryption
when implemented in a Clipper chip.
STANDARD
----------------------------------------------------------------- Chapter 1:0.89
In computing, a set of detailed technical guidelines used as a means of
establishing uniformity in an area of hardware or software development.
Computer standards have traditionally developed in either of two ways. The
first, a highly informal process, occurs when a product or philosophy is
developed by a single company and, through success and imitation, becomes so
widely used that deviation from the norm causes compatibility problems or
limits marketability. This type of de facto standard setting is typified by
such products as Hayes modems and IBM Personal Computers. The second type of
standard setting is a far more formal process in which specifications are
drafted by a cooperative group or committee after an intensive study of
existing methods, approaches, and technological trends and developments. The
proposed standards are later ratified by consensus through an accredited
organization and are adopted over time as products based on the standards
become increasingly prevalent in the market.
SYNCHRONOUS OPERATION
----------------------------------------------------------------- Chapter 1:0.90
Generally, any operation that proceeds under control of a clock or timing
mechanism.
SYNCHRONOUS OPTICAL NETWORK
(SONET)
----------------------------------------------------------------- Chapter 1:0.91
An international standard for transmitting information over optical fiber at
high speeds.
SYNCHRONOUS TRANSMISSION
----------------------------------------------------------------- Chapter 1:0.92
The serial transmission of a bit stream in which each bit occurs at a fixed
time interval and the entire stream is preceded by a specific combination of
bits that initiate the timing.
T-CARRIER SYSTEM
----------------------------------------------------------------- Chapter 1:0.93
A hierarchy of digital transmission capabilities designed to operate at various
rates, designated T1 (1.544 Mbps), T2 (6.312 Mbps), T3 (44.736 Mbps), and T4
(274.176 Mbps).
TELECOMMUNICATIONS
----------------------------------------------------------------- Chapter 1:0.94
A general term for the electronic transmission of information of any type,
including data, television pictures, sound, facsimiles, and so on.
TELECOMMUTING
----------------------------------------------------------------- Chapter 1:0.95
Also called electronic commuting. The practice of working in one location
(often, at home) and communicating with a main office in a different location
through a personal computer equipped with a modem and communications software.
TIME DIVISION MULTIPLE ACCESS
----------------------------------------------------------------- Chapter 1:0.96
A digital encoding scheme used in cellular service, this transmission method
allows users to simultaneously transmit on the same frequency by allocating
each user a discrete time slot.
TROJAN HORSE
----------------------------------------------------------------- Chapter 1:0.97
A computer program that conceals harmful code. A Trojan horse usually
masquerades as a useful program that a user would wish to execute.
TWISTED-PAIR WIRE
----------------------------------------------------------------- Chapter 1:0.98
A wire made of two separately insulated strands of wire twisted together.
VIRUS
----------------------------------------------------------------- Chapter 1:0.99
A computer program that can infect, replicate, and spread among computer
systems. Unlike the computer worm, a virus requires human involvement (usually
unwitting) to propagate.
WIDE AREA NETWORK
---------------------------------------------------------------- Chapter 1:0.100
A communications network that connects geographically separated areas.
WIRETAPPING
---------------------------------------------------------------- Chapter 1:0.101
The real-time collection of transmitted voice or data, and the sending of that
data in real time to a listening device. ("Real time" is defined as the actual
time that something, such as communication of information, takes place.)
WORM
---------------------------------------------------------------- Chapter 1:0.102
An independent computer program that reproduces by copying itself from one
system to another while traveling from machine to machine across the network.
Unlike computer viruses, worms do not require human involvement to propagate.
Most worms and viruses are closely related--they both spread and reproduce and
their effects can be identical.
RELATED GAO PRODUCTS
====================================================================== Chapter 2
Information Superhighway: Issues Affecting Development (GAO/RCED-94-285, Sept.
30, 1994).
Electronic Surveillance: Technologies Continue to Pose Challenges
(GAO/T-AIMD-94-173, Aug. 11, 1994).
IRS Automation: Controlling Electronic Filing Fraud and Improper Access to
Taxpayer Data (GAO/T-AIMD/GGD-94-183, July 19, 1994).
Communications Privacy: Federal Policy and Actions (GAO/OSI-94-2, Nov. 4,
1993).
IRS Information Systems: Weaknesses Increase Risk of Fraud and Impair
Reliability of Management Information (GAO/AIMD-93-34, Sept. 22, 1993).
Telecommunications: Interruptions of Telephone Service (GAO/RCED-93-79FS, Mar.
5, 1993).
FBI: Advanced Communications Technologies Pose Wiretapping Challenges
(GAO/IMTEC-92-68BR, July 17, 1992).
Economic Espionage: The Threat to U.S. Industry (GAO/T-OSI-92-6, Apr. 29,
1992).
Computer Security: Hackers Penetrate DOD Computer Systems (GAO/T-IMTEC-92-5,
Nov. 20, 1991).
Computers and Privacy: How the Government Obtains, Verifies, Uses, and
Protects Personal Data (GAO/IMTEC-90-70BR, Aug. 3, 1990).
Computer Security: Unauthorized Access to a NASA Scientific Network
(GAO/IMTEC-90-2, Nov. 13, 1989).
Computer Security: Virus Highlights Need for Improved Internet Management
(GAO/IMTEC-89-57, June 12, 1989).
*** End of document. ***