PACKET SATELLITE TECHNOLOGY REFERENCE SOURCES

Vinton G. Cerf
Defense Advanced Research Projects Agency

ABSTRACT

This paper describes briefly the packet satellite technology developed

by the Defense Advanced Research Projects Agency and several other

participating organizations in the U.K. and Norway and provides a

biblography of relevant papers for researchers interested in

experimental and operational experience with this dynamic

satellite-sharing technique.

INTRODUCTION

Packet Satellite technology was an outgrowth of early work in packet

switching on multiaccess radio channels carried out at the University of

Hawaii with the support of the Defense Advanced Research Projects Agency

(DARPA). The primary difference between the earlier packet-switched

ARPANET [1, 2] and the ALOHA system developed at the University of

Hawaii [3] was the concept of multiple transmitters dynamically sharing

a common and directly-accessible radio channel. In the ARPANET, sources

of traffic inserted packets of data into the network through packet

switches called Interface Message Processors (IMPs). The IMPs used high

speed point-to-point full-duplex telephone circuits [4] on a

store-and-forward basis. All packet traffic for a given telephone

circuit was queued, if necessary, in the IMP and transmitted as soon as

the packet reached the head of the queue. On such full duplex circuits

there is exactly one transmitter and one receiver in each direction.

The ALOHA system, on the other hand, assigned a common transmit channel

frequency to ALL radio terminals. A computer at the University of

Hawaii received packet bursts from the remote terminals which shared the

"multi-access" channel. Under the control of a small processor, each

terminal would transmit whenever it had traffic, and would await an

acknowledgement, on another frequency, dedicated to the service host. If

no acknowledgement was received, the terminal processor would transmit

again at a randomly chosen time. The system operated on the assumption

that no store-and-forward or radio relay was needed. The University of

Hawaii researchers later demonstrated that the ALOHA concept worked on a

satellite channel linking Hawaii and Nasa-Ames via NASA's ATS-1

satellite [5, 6]. A variety of more elaborate satellite channel

assignment strategies were developed and analyzed in the early 1970's

[7-13, 31].

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THE ATLANTIC PACKET SATELLITE EXPERIMENT (SATNET)

In 1973, DARPA began the development of a packet satellite system which

would support the sharing of a common, high speed channel among many

ground stations. Using an INTELSAT-IV satellite, the Atlantic Packet

Satellite experiment was carried out with the cooperation and support of

the British Post Office, COMSAT Corporation, Linkabit Corporation, and

Bolt Beranek and Newman Corporation, later joined by the Norwegian

Telecommunication Administration and the Norwegian Defense Research

Establishment (NDRE). Along with University College London and COMSAT

Laboratories, NDRE became one of the major users of the SATNET system.

During 1975-1978, SATNET underwent a broad range of performance

evaluations and tests. Since 1979, it has served as a stable support

for international experiments and demonstrations of command and control

technology of interest to DARPA, NDRE and the U.K. Royal Signals and

Radar Establishment (RSRE). Late in 1982, a ground station was added to

connect the German Aeronautics and Space Research Establishment (DFVLR)

into the system.

The early development of SATNET is outlined in [14]. The system design

is documented in [15-22]. Experience with the operation of the SATNET

is reported in [23-24] and experimental results in [25-26]. Potential

services which might be supported by this technology are discussed in

[27].

The integration of the packet satellite technology into a larger,

multiple packet network context is discussed in [28-29]. The system is

expected to continue in use to support joint research by DARPA, RSRE,

NDRE, DFVLR and UCL. DARPA and the U.S. Defense Communications Agency

are experimenting with a 3 megabit/second domestic packet satellite

system to determine whether packetized voice and data services can be

integrated economically using this technology. DARPA and the U.S. Naval

Electronic Systems Command recently demonstrated a Mobile Access

Terminal Network (MATNET) which uses packet satellite techniques to

support ship-ship and ship-shore communication over a shared FLTSATCOM

satellite channel [30].

ACKNOWLEDGEMENTS

The development of Packet Satellite technology has involved many

institutions and individuals, but special credit for the successful

realization of the SATNET and its successor systems must be given to Dr.

Robert E. Kahn, Director, Information Processing Techniques Office,

DARPA, for his continuous support and technical contributions throughout

the development and maturation of this technology.

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REFERENCES

1 L.G. Roberts and B.D. Wessler, "Computer Network Development to

Achieve Resource Sharing," Spring Joint Computer Conference, AFIPS

Proceedings, Vol. 36, 1970, pp. 543-549.

2 R.E. Kahn, "Resource Sharing Computer Networks," Proceedings of the

IEEE, Vol. 60, No. 11, November 1972, pp. 1397-1407.

3 N. Abramson, "The Aloha System - Another Alternative for Computer

Communications," AFIPS Conference Proceedings, Vol. 36, 1970, pp.

295-298

4 F.E. Heart, et al, "The Interface Message Processor of the ARPA

Computer Network, Spring Joint Computer Conference, AFIPS Proceedings,

1970, pp. 551-567.

5 R. Binder, et al, "Aloha Packet Broadcasting--a retrospect," AFIPS

Conference Proceedings, National Computer Conference, 1975, pp. 203-215.

6 N. Abramson and F. Kuo, Editors, Computer Communication Networks,

Prentice Hall, Englewood Cliffs, N.J., 1973.

7 L. Kleinrock and S. Lam, "Packet Switching in a Slotted Satellite

Channel," AFIPS Conference Proceedings, NCC, 1973, pp. 703-710.

8 L. Kleinrock and F. Tobagi, "Random Access Techniques for Data

Transmission over Packet Switched Radio Channels," AFIPS Conference

Proceedings, NCC, 1975, pp. 187-201.

9 L. Kleinrock and S.S. Lam, "Packet Switching in a Multiaccess

Broadcast Channel: Performance Evaluation," IEEE Transactions on

Communication, Vol. COM-23, 1975, pp. 410-423.

10 L.G. Roberts, "Aloha Packet System with and without Slots and

Capture," ACM SIGCOMM, Computer Communication Review, Vol 5, No. 2,

April 1975.

11 S.S. Lam and L. Kleinrock, "Packet Switching in a Multi-access

Broadcast Channel: Dynamic Control Procedures," IEEE Transactions on

Communication, Vol Com-23, September, 1975.

12 L.G. Roberts, "Dynamic Allocation of Satellite Capacity through

Packet Reservation," AFIPS Conference Proceedings, NCC, 1973, pp.

711-716

13 N. Abramson, "Packet Switching with Satellites," AFIPS Conference

Proceedings, NCC, 1973, pp. 695-702.

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14 R.E. Kahn, "The Introduction of Packet Satellite Communications,"

National Telecommunications Conference, Nov. 1979, p. 45.1.1-45.1.8.

15 I.M. Jacobs, et al, "CPODA - A Demand Assignment Protocol for

SATNET," Fifth Data Communications Symposium, Snowbird, Utah, 1977.

16 I.M. Jacobs, et.al, "General Purpose Satellite Networks,"

Proceedings IEEE, Vol 66, No. 11, November 1978, pp. 1448-1467.

17 I.M. Jacobs, et al, "Packet Satellite Network Design Issues,"

Proceedings, NTC, November 1979.

18 L. Palmer, J. Kaiser, S. Rothschild and D. Mills, "SATNET Packet

Data Transmission," COMSAT Technical Review, Volume 12, No. 1, Spring

1982, pp. 181-212.

19 Weissler, et al, "Synchronization and Multiple Access Protocol in

the Initial Satellite IMP," COMPCON, September 1978.

20 Hsu and Lee, "Channel Scheduling Snychronization for the PODA

Protocol," ICC, June 1978.

21 E. Killian and R. Binder, "Control Issues in a PODA Voice/Data

Satellite Network," ICC, June 1980.

22 C. Heegaard, J. Heller and A. Viterbi, "A Microprocessor-based PSK

Modem for Packet Transmission over Satellite Channels," IEEE

Transactions on Communications, COM-26, No. 5, May 1978, pp. 552-564.

23 P. Cudhea, D. McNeill, D. Mills, "SATNET Operations," AIAA 9th

Communications Satellite Systems Conference, Collection of Technical

Papers, 1982, pp. 100-105.

24 D.A. McNeill, et al, "SATNET Monitoring and Control," Proceedings

of the NTC, November 1979.

25 P.T. Kirstein, et al, "SATNET Applications Activities," Proceedings

of the NTC, November 1979.

26 W.W. Chu, et al, "Experimental Results on the Packet Satellite

Network," Proceedings of the NTC, November 1979.

27 E.V. Hoversten and H. L. Van Trees, "International Broadcast Packet

Satellite Services," ICCC Conference Proceedings, Kyoto, Japan,

September 1978.

28 V.G. Cerf and R.E. Kahn, "A Protocol for Packet Network

Intercommunication," IEEE Trans. on Comm., Vol. COM-23, May 1974, pp.

637-648

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29 V.G. Cerf and P.T. Kirstein, "Issues in Packet Network

Interconnection," IEEE Proceedings, Vol. 66, No. 11, Nov 1978, pp.

1386-1408

30 L. Evenchik, D. McNeill, R.P. Rice, F. Deckelman, et al, "MATNET,

an Experimental Navy Shipboard Satellite Communications Network, "IEEE

INFOCOM 82 Proceedings, March, 1982.

31 M.L. Molle and L. Kleinrock, "Analysis of Concentrated ALOHA

Satellite Links," Sixth Data Communications Symposium, Nov 27-29, 1979,

pp. 87-95.

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