Development of a TCP/IP for the IBM/370

ABSTRACT

This paper describes the design and implementation decisions that have been made in developing software to support the DARPA TCP/IP protocols for the IBM OS/370 environment at the University of California Division of Library Automation. The implementation is designed to support over 100 concurrent TCP connections, all of which are managed by a single program, which acts as a specialized sub-operating system. The system is optimized for line-by-line or screen-by-screen terminal traffic rather than character-by-character traffic. In addition, this TCP is designed to exploit the availability of the large main storage and processor speed available on the IBM/370. TCP/IP is generally considered to be a mature protocol specification; however, in the course of our implementation we found several parts to be either ambiguous or problematic — in particular, error handling and notification, ICMP and its relationship to other protocols, and synchronization of data flow with TCP callers. We also discuss problems encountered in trying to replace hardwired terminals in a public access environment with TCP and TELNET, and some protocol changes that would make these protocols more hospitable to our environment.

REFERENCES

• 1: University of California, Office of the Executive Director of University-Wide Library Planning, The University off California Libraries' A Plan for Development, 1978-1988 (Berkeley' The University of California, t977).
• 2: James Aagaard, Application Level Protocol Development for Library and Information Science Applications (Washington, D.C.' Council on Library Resources, 1982).
• 3: SRI Network ~nformation Center, I nternet Protocol Transition Workbook (Menlo Park, CA' Network Information Center, SP,t International, 1982).
• 4: Edwin Brownrig9 and Clifford Lynch, "Development of a Packet Switching Network for Library Automation," in Proceedings of the National Online Meetinq, New York, April 1983 (Medford, NJ' Learned Information, Inc., 1983), pp. 67-74.
• 5: David L. Shaughnessy and Clifford A. Lynch, "Telecommunications for an Online Catalog," Information Technology and Libraries 2, No. 1'73-86 (March 1983).
• 6: Edwin B. Brownrigg and Clifford A. Lynch, "Beyond the Integrated Library System Concept' Bibliographic Networking at the University of California," Proceedinqs o_ff the Second National Conference on Integrated Online Library_ Systems, Atlanta, Georgia, September 1984.
• 7: David Clark, Modularity and Efficiency in Protocol Implementation, RFC 817 (Cambridge, MA' Laboratory for Computer Science, Massachusetts institute of Technology, 1982).
• 8: D. Plummer, An Ethernet Address Resolution Protocol o_~r Converting Network Protocol Addresses to 48-Bit Ethernet Addresses for Transmission on Ethernet Hardware, P,FC 826 (Cambridge, MA' Laboratory for Computer Science, Massachusetts Institute of Technology, 1982).
• 9: Bolt Beranek and Newman, Interface Message Processor' Specifications for the Interconnection of a Host and an IMP, BBN Report 1822 (Cambridge, MA' Bolt Beranek and Newman, Inc., t981).
• 10: Andrew Malls, The ARPANET 1822L Host Access Protocol, P,F 878 (Cambridge, MA' Bolt Beranek and Newman, Inc., 1983).
• 11: Eric C. Rosen, Issues in Buffer Management, IEN 182, (Cambridge, MA' Bolt Beranek and Newman, 1980).
• 12: IBM Corporation, IBM SYSTEM/370 Principles of Operation (New York' IBM Corporation, 1981).
• 13: M1T Laboratory for Computer Science, PC/IP User's Guide (Cambridge, MA' Laboratory for Computer Science, Massachusetts Institute of Technology, 1984).
• 14: Jerome Saltzer, David Clark, John Romkey, and Wayne Gramlich, The Desi<top Computer as a Network Participa-~. (Cambridge, MA' Massachusetts Institute of Technology, 1985).
• 15: Mark Sherman, A Network Package for the Macintosh Using the DoD Internet Protocols, Dartmouth College, Hanover, NH, 1986
• 16: Carl Sunshine, "Addressing Problems in Multi-Network Systems," Proceedinqs INFOCOM 82, (Silver Spring, MD' IEEE Press, 1982), pp. 12-18.
• 17: Virginia Strazisar, How to Build a Gateway_, iEN 109 (Cambridge, MA' Bolt Beranek and Newman, Inc., 1979).
• 18: SRI Network information Center, Internet TELNET Proctocol and Options (Menlo Park, CA' Network Information Center, SP, I international, 1983).
• 19: Clifford Lynch, "Extensions to TELNET for Effective Break Support," ( 1984, unpublished).
• 20: Robin S. Clifford, TAg Users' Guide. BBN Report 4780 (Cambridge, MA' Bolt Beranek and Newman, Inc., 1982).

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.2 Network Protocols
          Subjects: Applications (SMTP, FTP, etc.)

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design
          Subjects: Network topology

General Terms:
Design, Documentation