RFC Errata
RFC 4566, "SDP: Session Description Protocol", July 2006
Note: This RFC has been obsoleted by RFC 8866
Source of RFC: mmusic (rai)
Errata ID: 2517
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Victor S. Osipov
Date Reported: 2010-09-13
Held for Document Update by: Robert Sparks
Section 5.14 says:
If the <proto> sub-field is "RTP/AVP" or "RTP/SAVP" the <fmt> sub-fields contain RTP payload type numbers. When a list of payload type numbers is given, this implies that all of these payload formats MAY be used in the session, but the first of these formats SHOULD be used as the default format for the session.
It should say:
If the <proto> sub-field is "RTP/AVP" or "RTP/SAVP" the <fmt> sub-fields contain RTP payload type numbers. When a list of payload type numbers is given, this implies that all of these payload formats MAY be used in the session, and these payload formats are listed in order of preference, with the first format listed being preferred; in that case the first acceptable payload format from the beginning of the list SHOULD be used for the session.
Notes:
The word ‘default‘ is improper here, because payload format is not implied, but explicitly indicated. This may lead to a misunderstanding and confusion.
The corrections are proposed in order to avoid confusion and to give complete clear instructions in case of multiple payload type numbers indicated.