Accept/Reject-Contact header(s)

SIP request contains Accept-Contact and Reject-Contact headers

Reject-Contact indicates URI’s not acceptable

Accept-Contact indicates ordered list of acceptable URI’s Indication by means of rules

set intersection and non-intersection of parameters
string match of URIs

Example:

Accept-Contact: sip:sales@acme.com ;q=0,
;media="!video" ;q=0.1,
;mobility="fixed" ;q=0.6,
;mobility="!fixed" ;q=0.4

In the second example, the caller does not want to talk to sales@acme.com, but has a preference for video and somewhat prefers the user’s fixed to non-fixed (i.e., mobile) terminal.

Transcript

[slide348] But now, we need to be able to say, hmm, what will I accept, and what are the things that I reject? So a reject contact says, no, I'm not going to accept that at all. The accept contact now takes the order of the URIs, and now applies a set of rules, does string matching, et cetera, and decides which one of these preferences get applied. So the caller is going to specify their set of preferences, and the callee is now going to receive them and say, OK, he wants it in English or Swedish, but not Spanish. OK, I have somebody who can speak English, and I'll send the call there, first preference. Or, they really want it, but they don't want video, OK, so then I need to send it to somebody and not select the video. Or there's a preference for fixed versus mobile connection, et cetera.