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Advanced Network Technology

June 1993

OTA-BP-TCT-

NTIS order #PB93-

Recommended Citation: U.S. Congress, Office of Technology Assessment, Advanced Network Technology--Background Paper, OTA-BP-TCT-1O1 (Washington, DC: U.S. Government printing Office, June 1993).

For sale by the U.S. Government Printing Office Supcl IIIILWIICIII (If [k)c ulllLlll. \lAll stop $s01’, $ Allllg((u. [)(’ 2(141? () ~?x ISBN 0-16 -041805-

R (^) eviewers

Rick Adams CEO UUNET Technologies

Robert Aiken Department of Energy

Raymond Albers Assistant Vice President Technology Planning Bell Atlantic

Alan Baratz Applications Solutions Director High Performance Computing and Communications IBM

Adam Beguelin Research Scientist School of Computer Science Carnegie Mellon University

Richard Binder Principal Scientist Corporation for National Research Initiatives

John Cavallini Deputy Associate Director Office of Scientific Computing Department of Energy

Bruce Davie Member of Technical Staff Broadband Packet Switching Research Bellcore

Darleen Fisher Associate Program Manager Division of Networking and Communications Research and Infrastructure National Science Foundation

Linda Garcia Senior Associate Office of Technology Assessment

Tom Hausken Analyst Office of Technology Assessment

Milo Medin Deputy Project Manager NASA Science Internet Office NASA

Paul Messina Director Caltech Concurrent Supercomputer Facility California Institute of Technology

Craig Partridge Senior Scientist Bolt Beranek and Newman

Daniel Stevenson Director Communications Research MCNC

Richard Thayer Director Federal Government Affairs AT&T

Bo Thomas Senior Federal Account Manager sprint

Philip Webre Principal Analyst Congressional Budget Office

AlIan Weis President Advanced Network & Services

Joan Winston Senior Analyst Office of Technology Assessment

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the reviewers. The reviewers do not, however, necessarily approve, disapprove, or endorse this background paper OTA assumes full responsibili- ty for the background paper and the accuracy of its contents.

iv

ALAN BUZACOTT Project Director

Administrative Staff

Liz Emanuel, Office Administrator Barbara Bradley, Secretary Karolyn St. Clair, PC Specialist

P reject Staff

John Andelin Assistant Director, OTA Science, Information, and Natural Resources Division

James W. Curlin Program Manager OTA Telecommunication and Computing Technologies Program

—

T

Introduction

and

Summary 1

he vision of the Nation’s future telecommunications system is that of a broadband network (see box l-A) that can support video, sound, data, and image communica- tions. Toward this end, the High-Performance Comput- ing Act of 1991 called for the Federal computer networks that connect universities and Federal laboratories to be upgraded to “gigabit networks” (see box l-B) by 1996. 1 This background paper reviews technologies that may contribute to achieving this objective, and describes the six prototype gigabit networks or “testbeds” that are being funded as part of the Federal High Performance Computing and Communications Program. These prototype networks are intended to demonstrate new communi- cations technologies, provide experience with the construction of advanced networks, and address some of the unresolved research questions.

FEDERAL SUPPORT FOR GIGABIT NETWORKING The High Performance Computing and Communications Program (HPCC) is a multiagency program that supports The HPCC research on advanced supercomputers, software, and networks. 2 In part, these technologies are being developed to attack the program funds “Grand Challenges”: (^) science and engineering problems in climate change, chemistry, and other areas that can only be the development solved with powerful computer systems. Network research is one of four components of the HPCC program, and represents about of new 15 percent of the program’s annual budget of close to $1 billion. (^3) communications

21 High-Perfo^ rmance^ Computing Act of 1991^ (HPCA),^ PL^ 102-194, Sec. 102(a). Office of Science and Twhnology Policy (OSTP), “Grand Challenges 1993: High technologies. Perfo 3 rmance Computing and Communications, ’ 1992. Ibid., p. 28.

2 I Advanced Network Technology

Box l-A–Broadband Networks

Computers and networks handle informa- Figure l-A-l—Digital Data tion as patterns of electronic or optical signals. Text pictures, sound, video, and numerical (^) Electrical or optical signal data can then be stored on floppy disks, used in computations, and sent from computer to ~

1 I^1 J

“ 1 computer through a network In digital/comput- ers or networks, the electronic or optical signals that represent information can take on one of (^) Binary representation two values, such as a high or a low voltage, which are usually thought of either as a “l” or “1” “o”^ “o”^ “l”^ “l”^

,,(),, H,,, (^) “o” “l” “o” a “O” (figure l-A-l). These 1s and 0s are called bits. SOURCE: Office of Technology Assessment, 1993. Different patterns of 1s and Os are used to represent different kinds of data Inmost computers, the letter ”A” is represented by the pattern of electronic signals corresponding to “01 000001 .“ To represent images, different patterns of bits are used to represent different shades (from Iight to dark) and odors. Sound is represented in much the same way, except that the patterns of bits represent the intensity of sound at points in time. The number of bits required to represent information depends on a number of factors. One factor is the quality of the representation. A good quality, high-resolution image would require more bits than a low-resolution image. Also, some kinds of information inherently require more bits in order to be represented accurately. A page of a book with only text might contain a few thousand characters, and could be represented with a few tens of thousands of bits. A page of image data on the other hand, could require millions of bits. Because images and video, which is a sequence of images, require many more bits to be represented accurately, they have strained the capabilities of computers and networks. Images take up too much space in a computer’s memory, and take too long to be sent through a network to be practical. The new high-capacity network technologies described in this background paper have the ability to support two-way digital, image, and video communications in a more efficient manner.

Digital Networks In the past, networks designed for video or sound used anabg transmission. In the old analog telephone network, for example, the telephone’s microphone converted the spoken sounds into an electrical signal whose

The other three components of the program target Network (NREN). The gigabit research program supercomputer design, software to solve the Grand Challenges, and research in computer science and mathematics. The HPCC program is the most visible source of Federal funds for the development of new communications technology. The networking com- ponent of the program is divided into two parts:

1. research on gigabit network technology, and 2) developing a National Research and Education

supports research on advanced network technol- ogy and the development of the six testbeds. The NREN program supports the deployment of an advanced network to improve and broaden net- work access for the research and education community. The High-Performance Computing Act of 1991 specfies that the NREN should operate at gigabit speeds by 1996, if technically possible. 4

(^4) HPCA, op. cit., footnote 1.

4 I Advanced Network Technology

Box l-B-Gigabit Networks

Much of the research described in this background paper is aimed at the development of gigabit networks, broadband networks that can transmit data atone billion bits per second or more (a “gigabit? is one billion bits; “gigabit per second” is abbreviated as Gb/s or Gbps). This represents a 20-fold increase over the most capable links in the networks that currently serve the research and education community. The current National Science Foundation network uses Iinks that transmit data at 45 million bits per second (megabits per second or Mb/s), and even this capacity has not been fully utilized because of bottlenecks in the network’s switches. The development of a gigabit network is an ambitious target-most current industry technology planning targets broadband networks with lower bandwidths, in the 150 million bits per second range. The basic outlines of the technology evolution of the DOD, NASA, DOE, and NSF networks that serve research and education were established in 1987 and 1989 reports issued by the Office of Science and Technology Policy. In the late 1980s, link bandwidths in the Federal networks were 1.5 Mb/s or less. The OSTP reports outlined a three-stage plan for the evolution of these networks to gigabit networks by the mid-to-late 1990s (see figure l-B-l). The gigabit target was also specified by the High-Performance Computing Act of 1991. The OSTP report envisioned that each generation of technology would move from an experimental phase in the Federal networks to commercial service. Figure l-B-l—Timetable for the National Research and Education Network

Stage 3 –.- -—.--.– —-- ---- Experimental networks Gbits/sec (^) 1 - —.————Research and development^ I Revolutionary (^) to commercial technology changes / Stage 2 45 mbps

h

Operational network (^) .-

Evolutionary changes Stage 1 1.5 mbps F’”- r–- ‘-:::= Stages 1^ &^2 R&D

89 90 91 92 93 94 95

services

........... ..........

96 SOURCE: Office of Science and Technology Policy, "The Federal High Performance Computing Program,” September 8, 1989.

Currently, the Federal agency networks are in the middle phases of the second stage, the operation of networks with 45 Mb/slinks. At the same time, research and development for the third stage, the deployment of gigabit networks, is underway. In practice, the network capacity will not jump directly from 45 Mb/s to gigabit rates. The next step will be to 155 Mb/s, then to 622 Mb/s, and then to greater than one gigabit per second. The bandwidths used in computer networks (1.5 Mb/s, 45 Mb/s, 155 Mb/s, and 622 Mb/s) correspond to standards chosen by manufacturers of transmission equipment. SOURCES: Office of Science and Technology Policy (OSTP), “A Research and Development Strategy for High Performance Computing,” Nov. 20, 1987; OSTP, “The Federal High-Performance Computing Program,” Sept. 8, 1989; High-Performance Computing Act of 1991 (HPCA), Public Law 102-194, Sec. 102(a).

—.

Chapter I–Introduction and Summary | 5

Box l-C-Computer Network Components A computer network has three main components: computers, links, and switches (figure 1 -C-l). The web of links and switches carry data between the computers. Links are made of copper (either “twisted pair” or “coaxial cable”) or fiber optics. Transmission equipment at each end of the fiber or copper generates the electrical or optical signals. There are also satellite and microwave links that send radio waves through the air. Fiber has several advantages over other types of Iinks--most notably its very high bandwidth. The fiberoptic links needed for gigabit networks are already commercially available. However, gigabit networks will not be deployed until research issues in other network components are addressed.

Figure l-C-l—A Simple Computer Network

Link {^
m -

1

( +^1 5 A^. El -

**-!

• 53** SOURCE: Office of Technology Assessment, 1993.

For example, new high-capacity switches are needed to keep pace with the higher bandwidth of fiber optic links. Just as railroad switches direct trains from track to track, the switches in computer networks direct information from link to link. As the information travels through the network, the switches decide which link it will have to traverse next in order to reach its destination. The rules by which the switches and users’ computers coordinate the transmission of information through the network are called protocols. While most computer networks are limited in their ability to carry high-bandwidth signals such as video, cable television networks are widely used to distribute television signals to homes. However, cable networks usually do not have switches. For this reason, they only permit one-way communications: the signal is simply broadcast to everyone on the network. Much of the network research today is devoted to the development of switches that would allow networks to support two-way, high-bandwidth communications. SOURCE: Office of Technology Assessment, 1993.

the faster flow of data. Broadband networks will sufficient flexibility to carry all types of informa- be more than simply higher bandwidth versions of tion efficiently. today’s networks, however. Networks will also be redesigned so that a single type of network can B The NREN carry video, sound, data, and image services. The One objective for the NREN is that it serve as existing telephone and data networks do not have an enabling technology for science and engineer-

Chapter 1–Introduction and Summary | 7

and universities and an estimated 1,000 high schools are connected to the Internet. 9 As the Internet user community becomes more diverse, there is a growing need for simplifying the applications and their user interfaces. This background paper primarily describes gigabit NREN applications and network technol- ogies. There are, however, several controversial policy issues related to the NREN program. 10 First, the scope of the NREN is uncertain. As a key component of the HPCC program, a clear role of the NREN is to serve scientists and engineers at Federal laboratories, supercomputer centers, and major research universities. This objective will be met primarily by upgrading the networks operated by the National Science Foundation (NSF), Department of Energy (DOE), and the National Aeronautics and Space Administration (NASA). However, there are several different visions of the extent to which the NREN program should also serve a broader academic community, such as libraries and schools. A second major issue concerns the “commer- cialization" of the NREN. The NREN will develop from the current Internet, which is increasingly used by government and businesses, not only by the research and education commu- nity. Several new commercial providers have emerged to offer Internet services to this market, which is not served by Federal agency networks. One of the goals of the NREN program is to continue this commercialization process, while at

the same time achieving the science and network research goals of the NREN program. There has been considerable uncertainty about the mecha- nisms by which this objective is to be achieved. The High-Performance Computing Act does not clearly specify the scope of the NREN or the mechanism for commercialization. NSF has had to address these issues in the course of developing a plan for the development of its network, which will be a central component of the NREN. These debates have slowed considerably the process by which NSF will select the companies that will operate its network. NSF’s original plan, released in the summer of 1992, is undergoing significant revisions (see box 5-A). As of May, 1993, a new plan had not been issued. It is increasingly unlikely that NSF will be able to deploy its next-generation network by the Spring of 1994, as was originally planned. In addition, the growing commercial impor- tance of networking is leading to greater scrutiny of the agencies’ choices of contractors to operate their NREN networks. DOE selected a contractor for its component of the NREN in thes summer of 1992, planning to deploy the new network in mid-1993. However, a losing bidder protested DOE’s selection to the General Accounting Office (GAO). In March, 1993, GAO overturned DOE’s choice of contractor and recommended that DOE revise its solicitation, conduct discus- sions with potential contractors, and allow con- tractors a new opportunity to bid. ll DOE has

g Darleen Fisher, Associate Program Manager, National Science Foundation, personal comrnunicatio% Feb. 11, 1993. 10 For ism= relat~ to tie NREN program, see Hearings before the House Subcommittee on Science,W. 12, 1992, Seti No. 120. 11 me dispute concem~ tie pmies’ interpretation of certain provisions in DOE’s Request for fiOfXMdS WV. ATM’ protested DOE’S selection of Sprint to be the contractor for the DOE network arguing successfully that the RFF had specified more fully-developed switches than had been proposed by Sprint as part of its bid. GAO ruled that the switches that Sprint planned to use did not comply with a provision in the RFP that proposals had to “conclusively demonstrate cument availability of the required end-to-end opemtional capability,” DOE, by contrast, was satisfkd that the switches had been developed to the level envisioned by the RFP and were appropriate to a program designed to explore leading-edge technology. DOE’s RFP had speci.fkd the use of “cell relay’ technology, which is the basis for both synchronous Transfer Mode (Am and Switched Multimegabit Data Service (SMDS) services. ATM is expected to play an important role in the future development of computer networking and the telecommunications industry, while SMDS is viewed primarily as an intermediate step towards ATM. DOE selected Sprint in large part because Sprint proposed to begin ATM services immediately, while AT&T bid a service based on SMDS and evolving to ATM only in

1994. Early deployment of ATM would have provided a valuable opportunity to evaluate and demonstrate a key telecommunicationsindustxy technology. Comptroller General of the United States, Decision in the Matter of AT&~ File B-250516.3, March 30, 1993.

8 I Advanced Network Technology

asked GAO to reconsider its decision. The DOE example raises questions about the effect of government procurement procedures on the abil- ity of federal agencies to act as pioneers of leading-edge network technology. The additional time that would be required to comply with GAO’s recommendations, added to the seven- month GAO process, would delay deployment of DOE’s network by over a year.

9 The Testbeds The HPCC program’s six gigabit testbeds (table l-l) are intended to demonstrate emerging high-speed network technologies and address unresolved research questions. While each testbed involves a different research team and is emphasizing dif- ~ f“nttoP@~=

s

is similarity in ignificant (^) their approach. progress has been The testbeds typ- made toward the ically consist of development of gigabit technology.

a high-speed net- work connecting I (^) three or four sites -universities, in- dustry laboratories, supercomputer centers, and Federal laboratories-with high-bandwidth opti- cal fiber. Located at each of the testbed sites are computers, prototype switches, and other network components. Each research group has both net- work and applications researchers-the applica- tions will be used to test different approaches to network design. The testbed program is administered by NSF and the Advanced Research Projects Agency 12 (ARPA). Five of the testbeds are jointly funded for 3 years by NSF and ARPA under a cooperative agreement with the Corporation for National Research Initiatives (CNRI). The principals of CNRI, a nonprofit organization, played signifi-

cant roles in the development of both the Arpanet and the Internet. 13 CNRI is responsible for org anizing the testbeds and coordinating their progress. Funding for the testbeds is modest, when compared to their visibility and the overall HPCC budget. The cooperative agreement with CNRI is for $15.8 million over 3 years. Most of the cost of building the networks has been borne by industry, in the form of contributions of transmission capacity, prototype switches, and research personnel. The testbeds are investigating the use of advanced network technology to match the needs of the NREN. There is an emphasis on delivering the highest bandwidths possible to the users and demonstrating the range of applications that would be used by leading-edge users of the NREN. Most of these applications are super- computer-based. For example, some applications use the network to link several supercomputers, allowing their combined processing power to compute complex simulations more rapidly. Many of the applications being investigated also use the network to enable visualization of the results of simulations or experiments. Initially, only a few users would have comput- ers powerful enough to need a gigabit network. However, the processing power of lower cost workstations and ordinary desktop computers is likely to continue to increase rapidly, as a result of advances in microprocessor technology. Giga- bit networks and the lessons learned from the testbeds will then be used more widely.

SUMMARY I Progress Significant progress has been made toward the development of gigabit network technology since 1987, when the Office of Science and Technology Policy (OSTP) noted that considerable research would be needed to determine the design of

12 Fo~erly the Defense Advanced Research Projects Agency (DARPA). 13 Dr. Row )?. ~ is fie~id~t of ~; Dr. Vtiton G. Cerf is Vim ~sident.

10 I Advanced Network Technology

gigabit networks. 14 There has been growing con- sensus within the technical community on many issues, and the development of the optical fiber links, switches, and other network components is underway. The testbeds represent the next step in the research-integrating the hardware and soft- ware components into a working network system and testing it with applications. The basic characteristics of the design of broadband networks began to emerge in the mid-1980s, supported by the results of simula- tions and small-scale experiments. Researchers’ objective was to develop networks that could support high band - widths and were

T

also sufficiently he testbeds have (^) flexible to sup- established a useful (^) port a range of model for network (^) services. One research. characteristic of these networks is the use of optical fiber links, which have the necessary capacity to support many new services, including bandwidth-intensive video- and image- based applications. The second major characteris- tic of the proposed designs for advanced networks is the use of ‘‘fast packet switches, ’ a new type of switch that has both the processing power to keep up with increases in link bandwidth and the flexibility to support several kinds of services. As these ideas began to emerge, computer and telecommunications companies initiated the de- velopment of the network components required for broadband networks. There appear to be no significant technological barriers to the develop- ment of the components required for the gigabit NREN. Transmission equipment of the type that would be required for the gigabit NREN is already becoming available commercially and is being used in the testbeds. Some fast packet

switches are also becoming commercially avail- able. Versions of these switches that operate at gigabit rates are in prototype form and will be incorporated in the testbeds over the coming year. The testbeds are looking to the next step in the research-the development of test networks. This is a systems integration task-developing the individual components is only part of the process of building an advanced network. There is often much to be learned about making the components work together and solving unforeseen problems in the implementation. In addition, there are research questions that can only be investigated with a realistic test network. The testbeds will provide a way to test various proposed ap- proaches to network design. Progress on the testbeds has been slower than expected, due to delays in making the transmis- ion equipment available and in completing work on the switches and other components. Switches are complex systems, requiring the fabrication of numerous electronic circuits. It was originally hoped that the optical fiber links could b e deployed and the gigabit switches and other components finished in time to have a year to experiment with the working testbed networks before the end of the program in mid-1993. It now appears that the testbeds will not be operational until the third quarter of 1993. The testbed program has been extended to permit a year’s research on the testbed facilities once they become operational.

H Testbed Concept The testbeds have established a useful model for network research. The design and construction of a test network fills a gap between the earlier stages of the network research-small scale experiments and component development—and the deployment of the technology in production

14 OfflW of Science and ‘lkchnoIo~ policy, “A Research and Development Strategy for High Performance Computing,” NOV. 20, 1987, p. 21.

networks. The testbed networks model the config- uration in which the technology is expected to be deployed—the test sites are separated by realistic distances and the networks will be tested with applications of the type expected to be used in the gigabit NREN. In addition, the participants in the testbeds will play important roles when the networks are deployed. The testbed research contributes in a number of ways to a knowledge base that reduces the risks involved in deploying advanced network technol- ogy. First, there are a number of research issues that are difficult to address without a working network that can be used to try different ap- proaches. Second, the systems integration process provides experience that can be applied when the production network is constructed. In many ways the experience gained in the process of getting the testbeds to work will be as valuable as any research done with the operational testbeds. Third, the testbeds serve to demonstrate the utility of the technology, which serves to create interest among potential users and commercial network providers. The relatively small amount of government money invested has been used primarily to organize and manage the testbeds and to encour- age academic involvement. The testbeds have mainly drawn on other government and industry investment. The organization of the testbeds as a collaborative effort of government, academic, and industry groups is essential, because of the many disciplines required to build and test a network. Industry has contributed expertise in a number of areas. For example, it would be too difficult and expensive for academic researchers to develop the high-speed electronics needed for the switches and other components. Academic researchers are involved in the Internet community, and have contributed ideas for new protocols and applica- tions. Other applications work has come from a

Chapter I-Introduction and Summary I 11

number of scientific disciplines and the super- computer community. One of CNRI’s main contributions was to encourage the involvement of the telecommuni- cations carriers in the testbeds. The transmission facilities required for the testbeds are expensive because of the long distances between the testbed sites and the demands for very high bandwidth. Most experimental work in the past was on small scale networks in a laboratory, due to the prohibi- tive cost of linking distant test sites. However, the carriers are installing the required transmission capacity and making it available to the testbeds at no cost. All three major interexchange carriers (AT&T, MCI, and Sprint), and most of the Regional Bell Operating Companies (RBOCs) are playing a role in the testbeds. The testbed research overlaps with industry priorities in some areas and not in others. The basic design of the networks—the types of switches and transmission equipment—reflects emerging industry concepts. However, much of the research agenda focuses on higher bandwidths and more specialized applications than will be used with commercial broadband networks in the near term. Only a few users will use the types of supercomputer-based applications being empha- sized by the testbeds. Of greater near-term com- mercial importance to industry are medium band- width ‘‘multimedia’ applications that require more bandwidth than can be supported by current networks, but significantly less than the gigabit speeds required by the supercomputer commu- nity.

1 Application of Testbed Research The testbed research is applicable both to the NREN and to other networks. The NREN will serve only the research and education community and is best viewed as only part of the broader national information infrastructure. 15 The scope of the national information infrastructure will in-

lfI For one view of tie relatiomtip ~Ween the NREN and the ‘‘National kfOMKitiOn masmcti~,’ (^) see Michael M. Roberts, “Positioning the National Research and Education Network” EDUCOMRcview, vol. 26, No. 3, s ummer^ 1991,^ pp. 11-13.

Chapter I-Introduction and Summary 113

within the Internet community. Also, the testbeds are not looking at applications that would be used by a broad range of users in the near term, or at issues related to making the Internet applications easier to use.

OTHER NETWORKS One of the roles of the NREN is to serve as a testbed in itself, demonstrating technology that will then be deployed more broadly in the national information infrastructure. The testbed program will also impact the evolution of the national information infrastructure more directly, bypassing the intermediate stage of deployment in the NREN. This is because the network technology used in the testbeds reflects near-term industry planning. While the testbeds have em- phasized higher bandwidths and more specialized applications than are of immediate commercial importance, the testbed networks reflect ideas that figure prominently in industry plans and,

wherever possible, use equipment that conforms to emerging standards. For example, many of the testbeds use a switching technology called Asynchronous Trans- fer Mode or ATM. This technology has become central to telecommunications industry planning because it is designed to support many different kinds of services-today’s telephone network switches are limited mainly to carrying ordinary telephone calls. ATM can support Internet-type services such as will be used in the NREN, and also video, voice, and other data communications services-the carriers plan to use ATM to enter a variety of markets. Although ATM has been widely accepted by the telecommunications in- dustry and progress has been made towards its implementation, there are a number of unresolved research issues. The testbeds are providing a large-scale opportunity to test this technology and possibly provide input to the standards process.

—— —.-.———.

T

he gigabit National Research and Education Network (NREN) is to develop from the current Internet, a ‘‘network of networks” that connects users in all parts of the United States and around the world. The Internet allows users to communicate using electronic mail, to retrieve data stored in databases, and to access distant computers. The network began as an Advanced Research Projects Agency research project to investigate computer networking technology, and in slightly over 20 years has grown into an essential infrastructure for research and education. The NREN initiative and associated research programs are intended to support the further evolution of research and education networking, broaden- ing access to the network and enabling new applications through the deployment of advanced technologies. Federal support to further the development of networks that support research and education communications is directed primarily at upgrading the Federal “backbone” networks that have formed the core of the Internet. l These networks include the National Science Foundation’s NSFNET backbone, the NASA Science Internet (NSI) (figure 2-l), the Department of Energy’s Energy Sciences Network (ESnet), and the Department of Defense’s DARTnet and Terrestrial Wideband Network (TWBnet). The NASA and DOE networks are primarily intended for traffic related to the mission of the supporting agency, while the current NSFNET backbone serves users in a broader range of disciplines in universities, supercomputer centers, and industry research laboratories. The DOD networks support research and development of new communications technologies. The Federal

The

Internet 2

Federal agency

networks will

f orm the core

of the gigabit

NREN.

1 Office of Science and lkchnology Policy (OSTP), “Grand Challenges 1993: High Perfo rmance Computing and Communications, ’ p. 18.

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