Hi, You can find the same discussion in the following url. http://www1.ietf.org/mail-archive/working-groups/sipping/current/ msg03076.html
Regards, Kumiko >Hi Charles, > >Thank you for your response. > >Section 16.10 says that a stateful proxy acts as an UAS for the CANCEL, >so 8.2 applies. And 8.2.6 says that a tag MUST be added. > >The text you quoted seems to be for responses forwarded upstream by a proxy. > >So my question is still: What tag must be used for the CANCEL response? > >My understanding is that a new tag, completely independent of any tag >received in previous provisional responses received for the INVITE, >should be generated and used. > >Charles Eckel wrote: >> Hi Marc, >> >> Its close. According to RFC 3261, the 200 for the CANCEL should not have >> a tag. >> >> 1xx and 2xx responses may be involved in the establishment of >> dialogs. When a request does not contain a To tag, the To tag >> in the response is used by the UAC to distinguish multiple >> responses to a dialog creating request. A proxy MUST NOT >> insert a tag into the To header field of a 1xx or 2xx response >> if the request did not contain one. A proxy MUST NOT modify >> the tag in the To header field of a 1xx or 2xx response. >> >> Cheers, >> Charles >> >> >> Marc Petit-Huguenin wrote: >> >>> Hi, >>> >>> Section 9.2 says that the To tag in a response to a CANCEL should be the >>> same than the To tag in the response to the original request. >>> >>> My understanding is that this rule only applies to an UAS, and not to a >>> proxy, as a proxy can send multiple responses with different To tags. >>> >>> Section 16.10 seems to support this, as it says that "[...] the element >>> is acting as a user agent server as defined in Section 8.2." No words >>> about reusing a previous To tag. >>> >>> So my question is: Is this call-flow correct? >>> >>> UAC Proxy >>> | INVITE | >>> |-------------->| >>> | | >>> | 100 tag=null | >>> |<--------------| >>> | | >>> | 180 tag=a | >>> |<--------------| >>> | | >>> | 180 tag=c | >>> |<--------------| >>> | | >>> | CANCEL | >>> |-------------->| >>> | | >>> | 200 tag=d | >>> |<--------------| >>> | | >>> | 487 tag=a | >>> |<--------------| >>> | | >>> | ACK | >>> |-------------->| >>> | | >>> >>> > >_______________________________________________ >Sip-implementors mailing list >[EMAIL PROTECTED] >http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
