I have a different opinion here. The answer need not be same as what A originally sent in offer. E.g. A sent two m-lines (audio and video). B suppressed one m-line (say video) because it didn't support video. Now, B sends two m-lines one of them carrying port 0. A can't reply with that m-line having non-ZERO port. There are more such examples. E.g. when A originally sent b= line with certain value (if offered all formats it supports). But, in the subsequent offer, it may choose only a subset of media formats which means potentially lower b= value. RegardsSatya T -----Original Message-----From: sip-implementors-bounces@xxxxxxxxxxxxxxxxxxxxx [mailto:sip-implementors-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Christer HolmbergSent: Wednesday, August 19, 2009 1:11 PMTo: 孙永光; IETF Sipping List; sip-implementors@xxxxxxxxxxxxxxxxxxxxx; discussion@xxxxxxxxxxxxxxxxxxx: Re: [Sip-implementors] how to response the offer Hi, I think A can answer however he wants. However, by using the SDP o- line one can explicitly indicate that nothing has changed from the previous SDP, so normally I guess the answer then wouldn't be modified either. Regards, Christer ________________________________ From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On Behalf Of ??? Sent: 19. elokuuta 2009 10:29 To: IETF Sipping List; sip-implementors@xxxxxxxxxxxxxxxxxxxxx; discussion@xxxxxxxxxxxx Subject: how to response the offer Dear All I have a question about How to respond the offer , the scenario is as following A call B , and the offer and answer is ok , after a while , A receives a B 's REINVITE which includes the same SDP as it just answered before now, How does A respond it ? does A must respond the B's new offer with the same SDP as the offer it sent previously? could you give some advice ? Thanks SunYongGuang -- msn:yongguangsun@xxxxxxxxxxx <mailto:msn%3Ayongguangsun@xxxxxxxxxxx> _______________________________________________Sip-implementors mailing listSip-implementors@xxxxxxxxxxxxxxxxxxxxxxxxxx://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors_______________________________________________Sipping mailing list https://www.ietf.org/mailman/listinfo/sippingThis list is for NEW development of the application of SIPUse sip-implementors@xxxxxxxxxxxxxxx for questions on current sipUse sip@xxxxxxxx for new developments of core SIP
