RFC 3168, "The Addition of Explicit Congestion Notification (ECN) to IP", September 2001Source of RFC: tsvwg (tsv)
Errata ID: 3636
Publication Format(s) : TEXT
Reported By: Mirja Kühlewind
Date Reported: 2013-06-04
Rejected by: Martin Stiemerling
Date Rejected: 2013-07-11
Section 6.1.1. says:
If the TCP connection does not wish to use ECN notification for a particular packet, the sending TCP sets the ECN codepoint to not-ECT, and the TCP receiver ignores the CE codepoint in the received packet.
It should say:
If the TCP connection does not wish to use ECN notification for a particular packet, the sending TCP sets the ECN codepoint to not-ECT.
CE should not be set on not-ECT capable packets. If this happens anyway, the CE codepoint would overwrite the ECT codepoint. Thus there is no way for the receiver to know it should ignore the CE codepoint; the sentence is therefore nonsensical.
See discussions in the tsvwg (http://www.ietf.org/mail-archive/web/tsvwg/current/msg11989.html)