Subject: [Sip] Session-level value overriden by media-level value in SDP (RFC 4566)

From: "Jagan Mohan" <[email-masked]>
Date: Wed, 12 Dec 2007 11:54:04 +0530

Hi,

      For example, a SIP message has the following SDP:

      v=0
      c=IN IP4 0.0.0.0
      t=2873397496 2873404696
      m=audio 49170 RTP/AVP 0
      a=sendonly

   I would like to know whether a=sendonly or c=IN IP4 0.0.0.0 should take
into effect in this particular case.

   From RFC 4566:
   ============

   Section 5, Page 8 mentions the following:

   An SDP session description consists of a session-level section
   followed by zero or more media-level sections.  The session-level
   part starts with a "v=" line and continues to the first media-level
   section.  Each media-level section starts with an "m=" line and
   continues to the next media-level section or end of the whole session
   description.  In general, session-level values are the default for
   all media unless overridden by an equivalent media-level value.

  Section 5, Page 10 mentions the following:

   [The connection ("c=") and attribute ("a=") information in the
   session-level section applies to all the media of that session unless
   overridden by connection information or an attribute of the same name
   in the media description.]

   I find the above statements to be slightly contradictory.

   Please clarify.

Thanks,
Jagan
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