It's a fascinating problem. In a way, inserting a unregistered attribute is forbidden, but any recipient is forbidden from objecting to it.
OTOH, if the attribute is unregistered, you can't really say that the endpoint using it in its answer is *wrong*, since there's no fixed definition of the semantics of the attribute. Perhaps the endpoint simply means "I received CustomAttribute:GID in the offer." I think the actual answer is to be clever, and to define CustomAttribute in such a way that simply copying it into the answer unchanged can be detected and ignored. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
