Subject: Protocol Action: End-to-end Performance Implications of Links with Errors to BCP

From: The IESG <[email-masked]>
Date: Thu, 19 Jul 2001 14:55:57 -0400

The IESG has approved the Internet-Draft 'End-to-end Performance
Implications of Links with Errors' <draft-ietf-pilc-error-08.txt> as a
BCP.  This document is the product of the Performance Implications of
Link Characteristics Working Group.  The IESG contact persons are
Allison Mankin and Scott Bradner.

Technical Summary
 
   The rapidly-growing Internet is being accessed by an
   increasingly wide range of devices over an increasingly wide
   variety of links. At least some of these links do not provide
   the degree of reliability that hosts expect, and this expansion into
   unreliable links causes some Internet protocols, especially TCP
   [RFC793], to perform poorly.

   Specifically, TCP congestion control [RFC2581], while
   appropriate for connections that lose traffic primarily
   because of congestion and buffer exhaustion, interacts badly
   with uncorrected errors when TCP connections traverse links with
   high uncorrected error rates. The result is that sending TCPs may
   spend an excessive amount of time waiting for acknowledgements that
   do not arrive, and then, although these losses are not due to
   congestion-related buffer exhaustion, the sending TCP transmits at
   substantially reduced traffic levels as it probes the network to
   determine "safe" traffic levels.

   This document discusses the specific TCP mechanisms that are
   problematic in these environments.  The document includes a metric
   to help determine if an environment has the level of non-
   congestive loss that warrants concern for TCP.  It follows with
   informational discussion of each TCP issues capped with a
   Recommendation section pointing to existing standards for
   TCP behavior that should be be invoked to mitigate problems.
   Use of intermediate devices (performance-enhancing proxies) is
   not recommended.

Working Group Summary

   The working group had solid consensus to advance this document,
   after working carefully through the cases in it.

Protocol Quality

   Allison Mankin reviewed the spec for the IESG.

Note to RFC Editor
        Changes section should be removed before publication as a RFC.