On 02/22/2012 04:11 PM, Iñaki Baz Castillo wrote: > 2012/2/22 Paul Kyzivat<[email protected]>: >> If I was in the position of needing to construct a temporary offer, with >> no ability to handle media myself, and no knowledge of what the caller >> might be looking for or what is likely to be offered later, I would be >> inclined to offer audio with G.711 and a black holed IPv4 media address. >> Or maybe I would offer both audio and video and a whole bunch of codecs, >> still with black holed IPv4 address. But if possible it would be better >> to tailor the offer to the sorts of capabilities that will be offered later. > > And all of this makes the requirement of an SDP offer in the first 1XX > response really a pain, am I wrong? > > BTW, what about if a SIP proxy/server receives an INVITE with no SDP > offer and "Require: 100rel" and the SIP proxy/server wants to reply a > 181 "Call Is Being Forwarded" or 182 "Queued" before ruting the call > to the appropriate destination (imagine an specific SIP application > server for an incoming call-center)? why should such a SIP > server/proxy include an SDP offer in the 181/182 response? It makes no > sense at all, and hence the requirement within RFC 3262 is wrong > (IMHO). > > Maybe this annoying requirement is inheritance from RFC 3261 in which > is stated that "the first reliable response to an INVITE MUST contain > an SDP answer/offer (depending on the presence of SDP offer in the > INVITE or not)?
Yes, that's exactly where it comes from. The usage of 100rel/PRACK turns that 181/182 response into a 'reliable response'. -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies Jabber: [email protected] | SIP: [email protected] | Skype: kpfleming 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA Check us out at www.digium.com & www.asterisk.org _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
