As far as I can tell, a 406 is returned when the UAS on the other side cannot formulate a response with content-type acceptable to the sender (as indicated in the Accept-header it sent). A 488 is returned when the UAS can satisfy the Accept-header but the session description in the request is not acceptable. There is also a 606 which tells that ALL UASs for that user don't accept the session description (a 488 only rejects the request to that particular R-URI).
There might be a bug in bis-09 (Jonathan, we need your comments here). More comments below. Regards, Hisham > -----Original Message----- > From: ext Feldman, Michael [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, May 21, 2002 6:45 PM > To: [EMAIL PROTECTED] > Subject: [Sip-implementors] 406 vs 488 responses > > > When should a 406 (Not Acceptable) be sent verse a 488 (Not Acceptable > Here)? > > > the UPDATE draft mentions > an update could be reject a codec change with a 488, > the bis9 draft mentions > a Re-INVITE codec change is rejected with a 406 or a 488? > > thanks, > mike feldman > [EMAIL PROTECTED] > > > > > > bis9 page 18, section 4: > > This is accomplished by sending a re-INVITE containing a new media > description. This > re-INVITE references the existing dialog so that the other > party knows that > it is to > modify an existing session instead of establishing a new > session. The other > party > sends a 200 (OK) to accept the change. The requestor responds > to the 200 > (OK) with an > ACK. If the other party does not accept the change, he sends an error > response such as > 406 (Not Acceptable), which also receives an ACK. This is a bug, it should be 488. > > but bis 9 in section 14.2 page 90: > If the new session description is not acceptable, the UAS can > reject it by > returning a 488 (Not Acceptable Here) response to the re-invite. > > > draft-ietf-sip-update-02, section 5.2: > > If the new session description is not acceptable, the UAS can > reject it by > returning a > 488 (Not Acceptable Here) response for the UPDATE. This is correct. > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
