OSI connectionless transport services on top of UDP Applicability Statement for Historic Status
draft-bradner-1240.his-01

Network Working Group                                      Scott Bradner
Internet-Draft                                        Harvard University
                                                            January 1999

              OSI connectionless transport services on top
           of UDP Applicability Statement for Historic Status

                    <draft-bradner-1240.his-01.txt>

1. Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
   working documents as Internet-Drafts.

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   This document will expire before June, 1999. Distribution of this
   draft is unlimited.

2. Abstract
   RFC 1240, "OSI connectionless transport services on top of UDP", was
   published as a Proposed Standard in June 1991 but at this time there
   do not seem to be any implementations which follow RFC 1240.  In
   addition there is a growing concern over using UDP-based transport
   protocols in environments where congestion is a possibility.

3. Copyright Notice
   Copyright (C) The Internet Society (1999).  All Rights Reserved.

4. Use of RFC 1240 Technology
   A message was sent to the IETF list in October 1998 seeking any
   information on the actual use of the technology described in RFC
   1240.  A number of responses were received, including from the
   International Organization for Standardization (ISO), the keeper of
   the OSI protocols.  None of these messages pointed to any current use

Bradner                                                         [Page 1]
Internet-Draft            RFC 1240 to Historic              January 1999

   for this technology.  Most of the messages which made any
   recommendation did recommend that RFC 1240 be moved to historic.

5. Responsiveness to Congestion
   Since 1991 there has been a great deal of experience with the
   complexities of dealing with congestion in the Internet.  Congestion
   control algorithms have been improved but there is still work
   underway to further understand the issues.  In this environment any
   UDP-based protocol is somewhat worrisome since quite frequently
   people who use UDP-based protocols invent their own reliability and
   congestion control functions which may not include the results of the
   current state of the art.  This leads to a danger of congestion
   collapse with potentially quite serious consequences for the network
   in which it is run.   See RFC 896 for a discussion of congestion
   collapse.

   In the case of RFC 1240, the authors seemed to assume that if some
   level of reliability was needed in an RFC 1240 environment that the
   reliability algorithms and the congestion control algorithms which
   would then be required would reside in the OSI protocols running over
   the UDP transport.  It is far from clear that any perceived
   advantages of running over UDP would not be eclipsed by the
   difficulties experienced in trying to create a reasonable congestion
   control algorithm.  Implementers would likely find that running over
   TCP as RFC 2126 describes is the better choice.

6. Conclusion
   Due to the lack of use of the technology described in RFC 1240 and
   the issues surrounding congestion control in the Internet, RFC 1240
   should be reclassified as Historic and its implementation actively
   discouraged.

7. Security Considerations
   This type of non-protocol document does not directly effect the
   security of the Internet.

8. References
   RFC 896: J. Nagle, "Congestion control in IP/TCP internetworks",
      January 1984
   RFC 1240: C. Shue, W. Haggerty, and K. Dobbins. - "OSI connectionless
      transport services on top of UDP: Version 1.", June 1991
   RFC 2126: Y. Pouffary, A. Young, "ISO Transport Service on top of TCP
      (ITOT)", March 1997

9. Author's Address
   Scott Bradner
   Harvard University

Bradner                                                         [Page 2]
Internet-Draft            RFC 1240 to Historic              January 1999

   1350 Mass Ave, rm 876
   Cambridge, MA
   02138
   USA

   phone: +1 617 495 3864
   sob@harvard.edu

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Bradner                                                         [Page 3]