If the proxy is supporting History-Info, it should add a header for every retarget or forwarding of a Request. For Loose routing, the proxy is retargeting - it's just capturing the next hop in the Route header only. The text in RFC 4244 indicates that with Loose Routing, the Request-URI is the same in each entry, but you do still get information as to the number of hops, etc. This could still be useful to some applications - for example, you can still build the tree for the path of the request. Obviously, there are some limitations to the usability of H-I in these cases.
There is text in RFC 4244 in section 4.3.3.1 that specifies H-I is added as a request is forwarded, so it should insert H-I irrespective of whether the Request URI has changed as you suggest below. It might be helpful to both add an example showing how the trees of the path of the request are helpful, as well as showing an example in the case of loose routing when we update RFC 4244. And, perhaps something to clarify is that in the case of loose routing the hops are reflected in the Route Header. Regards, Mary. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Siddharth Sent: Thursday, December 11, 2008 7:31 AM To: [email protected] Subject: [Sip] Query on History-Info. Hi all, I had a quick query on History-Info (RFC 4244). Apologies if this has been discussed already. If so, I would be grateful if you could provide the pointer to the relevant thread. Once a proxy determines that it may include the History-Info header for a particular request (based on local policy, privacy settings etc) should it insert a History-Info header only if the proxy had done a retargeting for this request? Or should it insert a History-Info header irrespective of whether the request uri is changed by itself or not? The following text in the RFC: "Note that in the case of loose routing, the Request-URI does not change during the forwarding of a Request; thus, the capturing of History-Info for such a request would result in duplicate Request-URIs with different indices." seems to suggest that the proxy should always insert the History-Info header even if the Request-URI is not changed. Is this understanding correct? Thanks and Regards, Siddharth _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [email protected] for questions on current sip Use [email protected] for new developments on the application of sip _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [email protected] for questions on current sip Use [email protected] for new developments on the application of sip
