Re: [MMUSIC] ABNF syntax in 3388bis

[Gonzalo Camarillo <[e-mail]>]

Hi,

Ali C. Begen (abegen) wrote:
> So, if an SDP from entity X says "a=group:FID" without any specific
> mid values, would that mean entity X can support group:FID semantics
> on any media streams? Is this for something like capability
> negotiation because that line does not mean anything specific (at
> least to me)?

yes, the section is indeed call Capability Negotiation and was already 
in RFC3388:

http://tools.ietf.org/html/rfc3388#section-8.3

8.3 Capability Negotiation


    A client that understands "group" and "mid" but does not want to make
    use of them in a particular session MAY want to indicate that it
    supports them.  If a client decides to do that, it SHOULD add an
    "a=group" line with no identification-tags for every semantics it
    understands.

    If a server receives an offer that contains empty "a=group" lines, it
    SHOULD add its capabilities also in the form of empty "a=group" lines
    to its answer.

Cheers,

Gonzalo