> >5> if you send an options request, how does the other > >side notify about its capabilities and which all of > >them??( does it tell abt its media capabilities too). > > "Options" method is responded with an OK. OK response shall contain all the information about supported media capabilities (codec), supported methods, option tags, content types, etc
rgds jai > Please see my response in line below.. > > varun wrote: >>Hi, >>1> In the invite offer, lets say a list of codecs with >>send/recv mode are send..! >>So in 200 OK, the calle just picks one of these codecs >>and replies back or it can also send a list of codecs >>with a ordered preference?? >> > In 3261, the callee is supposed to honor the caller codec preference > unless it has a compelling reason to choose its own preference. > Therefore, in general case, the caller will response in 200 OK with the > codec that is listed first in the caller's SDP >>2> Also, after sending INVITE, the caller opens its >>media port ( ready to receive media)...how does it >>receive media from calle before 200 ok/or any >>provisional reponse...i mean since 200 OK/provisional >>response would specify the actual common media >>format..! >> > Early dialog can have media flow before 200 OK. Early dialog can happen > when the UAS sends 183 with SDP and there could be RTP after that, no > need to wait for 200 OK. And again, the SDP in 183 message would honor > the caller's codec preference. >>3> Also, can send and receive media formats be >>different in a SIP call ( like h.323)...! >>This would require multiple offer-Answer ??? >> > In SIP, if one of the parties wants to change the media type, it will > need to re-INVITE or UPDATE with SDP. The other party will accept with > 200 OK. The media type should be the same for both send and receive > though. I don't think you can have caller sends one type of media and > the other sends another type and the call would work. >>4> what abt update method..how does it modify he >>negotiated media formats?? >> > UAC would send the UPDATE with its codec preference in SDP. The UAS will > determine if it can honor the UAC's preference and respond with 200 OK > that has its codec of choice in the SDP >>5> if you send an options request, how does the other >>side notify about its capabilities and which all of >>them??( does it tell abt its media capabilities too). >> >>Would appreciate your response. >> >>Thanks >>Naveen >> >>__________________________________________________ >>Do You Yahoo!? >>Tired of spam? Yahoo! Mail has the best spam protection around >>http://mail.yahoo.com _______________________________________________ >>Sip-implementors mailing list >>[email protected] >>https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >> >> > > _________________________________________________________________ > Express yourself instantly with MSN Messenger! Download today it's FREE! > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
