Subject: Question about SDP session name

From: "rao v" <[email-masked]>
Date: Mon, 31 Jul 2000 19:40:34 EDT

Hello.

I have just started with SDP and I have a question regarding the SDP session 
name. RFC 2327 states that the session name (the 's=' line)  is mandatory, 
however, it is not very clear to me if it is syntactically correct to have 
an 's=' line without actually specifying a session name, i.e. 's=' followed 
by CRLF, as in:

        v=0
        o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4
        s=
        i=A Seminar on the session description protocol
        u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
        e=[email-masked] (Mark Handley)
        c=IN IP4 224.2.17.12/127
        t=2873397496 2873404696
        a=recvonly
        m=audio 49170 RTP/AVP 0
        m=video 51372 RTP/AVP 31
        m=application 32416 udp wb
        a=orient:portrait

Clarification that anyone provides will be appreciated.
Thanks a lot!

Rao V.
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---

From: Dirk Kutscher <[email-masked]>
Date: 01 Aug 2000 17:14:55 +0200

>>>>> "Rao" == rao v <[email-masked]> writes:

    Rao> Hello.
    Rao> I have just started with SDP and I have a question regarding the SDP session 
    Rao> name. RFC 2327 states that the session name (the 's=' line)  is mandatory, 
    Rao> however, it is not very clear to me if it is syntactically correct to have 
    Rao> an 's=' line without actually specifying a session name, i.e. 's=' followed 
    Rao> by CRLF, as in:

    Rao>         v=0
    Rao>         o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4
    Rao>         s=
    Rao>         i=A Seminar on the session description protocol
    Rao>         u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
    Rao>         e=[email-masked] (Mark Handley)
    Rao>         c=IN IP4 224.2.17.12/127
    Rao>         t=2873397496 2873404696
    Rao>         a=recvonly
    Rao>         m=audio 49170 RTP/AVP 0
    Rao>         m=video 51372 RTP/AVP 31
    Rao>         m=application 32416 udp wb
    Rao>         a=orient:portrait

No, RFC 2327 mandates that the session-name field contain at least one
character.

This issue has been discussed before -- RFC 2543 (SIP) allowed the
session-name in a SDP-content to be empty for invitations to two-party
sessions. draft-ietf-sip-rfc2543bis-00.txt has been corrected to that
respect. If you do not want to specify a session name (because the
corresponding information is provided by other means), the best
current practice would be to use a space character.

-- 
	Dirk