On Tue, 2009-09-01 at 14:13 +0530, Manjunath Warad wrote: > If a UA receives a request in a spiralled way then shouldn't the > From Tag and Call-ID same as the originated request?
> Should the UA accept the received request as spiral if call-ID is > same and From tag is different? Please let me know if there is any business > use case of such scenario if you have come across. > Since the match algo is not well defined for spiral in RFC, we need > a reference. Strictly speaking a UA cannot receive a spiraled request, since the request cannot have passed through the UA before. A UA can receive a "merge" request, that is, a request which is another fork of a request that it has received before. Merged requests are detected per section 8.2.2.2 of RFC 3261: the Call-Id, the from-tag, and the CSeq are the same. As you notice, if the Call-Id's are the same, the from-tag's must be the same, but if some intermediate element has modified the from-tag, it is clear that the UA should consider the requests to not be merged requests. In regard to a proxy, which can receive a spiraled request, that is, a request one of whose ancestral requests passed through the proxy: The proxy does not need to be aware that the request is spiraled, since it only needs to recognize "hop-by-hop transactions", which are identified by the branch parameter value of the topmost Via header. Dale _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use sip-implement...@cs.columbia.edu for questions on current sip Use sipp...@ietf.org for new developments on the application of sip
