Serial link protocol design: A critique of the X.25 standard, level 2

ABSTRACT

There are certain technical design principles for link communication protocols which, if followed, result in a protocol that is less complex in both concept and implementation, but at the same time provides better service, than if the principles are not followed. These principles include modularization into sub-protocols, symmetry between the nodes on the link, and use of the state-exchange model of a conversation rather than the command-response model. The principles are described, the extent to which they are followed by the standard protocol X.25, level 2, is examined, and a protocol adhering to them is presented.

REFERENCES

• 1: Sloan, L. J.: Limiting the lifetime of packets in computer networks. Fourth Conference on Local Computer Networks. Minneapolis, Minn. (1979).
• 2: Fletcher, J. G. and Watson, R. W.: Mechanism for a reliable timer-based protocol. Computer Networks 2, No. 4-5, pp. 271-290 (1978).
• 3: Lawrence L. Garlick , Raphael Rom , Jonathan B. Postel, Reliable host-to-host protocols: Problems and techniques, Proceedings of the fifth symposium on Data communications, p.4.58-4.65, September 27-29, 1977, Snowbird, Utah, United States [doi>10.1145/800103.803343]
• 4: International Telegraph and Telephone Consultative Committee: Recommendation X.25. Geneva, Switzerland (1980).
• 5: Jablonski, Z.: Possible improvements for the HDLC protocol. Unpublished.
• 6: Donnan, R. A. and Kersey, J. R.: Synchronous data link protocol: a perspective. IBM System Journal 13, No. 2, pp. 140-162, (1974).
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• 8: Fletcher, J. G.: A serial communication protocol. Computer Design 17, pp. 77-86 (1978).

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.2 Network Protocols
          Subjects: Protocol architecture (OSI model)

Additional Classification:
  B. Hardware
  B.4 INPUT/OUTPUT AND DATA COMMUNICATIONS
      B.4.2 Input/Output Devices
          Subjects: Channels and controllers

General Terms:
Design