rsw2111 <rsw2...@columbia.edu> writes: > 4028 is clear that the supported header in the initial INVITE indicates > whether or not refreshers are supported by the UAC. In this case, there is > no Supported header in the initial INVITE, so it can be assumed that the > A-side does not support refreshers. That being the case, is the B-side > allowed to sending the Session-Expires: 3700;refresher=uac and Min-SE: 600 > in the re-invite?
A UA is allowed to send any header it chooses as long as it conforms to the RFCs, regardless of the information it has about the capabilities of the peer UA. There have been long discussions regarding the "Supported" header, and the conclusion is that the information provided by "Supported" is not very reliable. There are many situations where the peer UA of a dialog can change, or its capabilities can change, without the UA being aware of that fact. At best, the information in "Supported" can only be considered a suggestion. So a UA may always attempt to invoke any feature of the peer UA, and must always be prepared for its use of any feature to be rejected. Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
