RFC 4566, "SDP: Session Description Protocol", July 2006

Note: This RFC has been obsoleted by RFC 8866

Errata ID: 5595
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Gavin Scallan
Date Reported: 2019-01-08

Section 5 says:

An example SDP description is:

      v=0
      o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5
      s=SDP Seminar
      i=A Seminar on the session description protocol
      u=http://www.example.com/seminars/sdp.pdf
      e=j.doe@example.com (Jane Doe)
      c=IN IP4 224.2.17.12/127
      t=2873397496 2873404696
      a=recvonly
      m=audio 49170 RTP/AVP 0
      m=video 51372 RTP/AVP 99
      a=rtpmap:99 h263-1998/90000

It should say:

An example SDP description is:

      v=0
      o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5
      s=SDP Seminar
      i=A Seminar on the session description protocol
      u=http://www.example.com/seminars/sdp.pdf
      e=j.doe@example.com (Jane Doe)
      c=IN IP4 224.2.17.12/127
      a=recvonly
      t=2873397496 2873404696
      m=audio 49170 RTP/AVP 0
      m=video 51372 RTP/AVP 99
      a=rtpmap:99 h263-1998/90000

Notes:

In section 5 it indicates that the SDP lines MUST appear in the exact order given at the top of Page 9.
The order that is shown indicates that the Session Attributes appear before the Time Description.

However in the example included in this section which explains that Media Attributes have precedence over Session Attributes for a media stream contradicts the order as the Session Attribute of sendonly is included below the Time Description.

Either the example is incorrect, or the normative description is poorly explained and some variability in the order of lines in the SDP is allowed.

Report New Errata