Barry, My suggestion would be to add UPDATE to the Allow header, but to return a 488 response and include an empty Accept header. That should signify to the UAC that your UAS does not accept message bodies for UPDATE methods. I don't think it's stated explicitly, but I interpret the Accept header to be method-specific (It makes sense to me that some method types would support message bodies that others don't). So it shouldn't have any implications on what message bodies your UAS supports for INVITE methods.
Note that, even if this is correct according to a precise interpretation of the specs, there's no guarantee that all UAC implementations will get the hint. So I think this whole scenario puts you on thin ice, as far as interoperability goes. But I suspect you knew that already. Alternatively, you could indicate support for session timers by putting the "timer" option tag in the Supported header, but not put UPDATE in the Allow header. I don't think it's a good idea, because it's quite inconsistent. But it might just do the trick (or it might confuse the UAC even further. Who knows?) Just some food for thought ... good luck. -- Gary Cote www.awardsolutions.com _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
