In the section 10.25 of bis-04, which discusses the From header, it is specified - The "tag" value MUST be globally unique and cryptographically random with at least 32 bits of randomness. It SHOULD differ for each call leg. 1. Why is this rule specified for the From header only? It would appear that this is also true for To headers. 2. Further, why should different legs have different FROM tags? When is this useful? It seems that it is a lot simpler if all legs from a UA for a given callid have the same local tag. The To tag in responses serves to identify the forked UAS legs to the UAC. What is the use of a unique From tag in each leg? What call scenarios need this? 3. Specifically, when a 3xx is received with a To tag, and a new leg is created to launch the redirected INVITE, should a new From tag be generated and if so what purpose is served thereby? The same question arises regarding a triggered INVITE with same call id, on receipt of a Refer Regards, Venkat _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
