On 07/07/2010 03:37 AM, rupert.or...@bt.com wrote:
I have SER sitting in front of Asterisk. It is useful to me for Call Forking purposes as I do not think Asterisk handle multiple registered endpoints (against a single username)
You are correct.
However, since both SER and Asterisk are Registrars, and Asterisk need toknow register info to work properly, I need to forward Registers from SER to Asterisk....
There is an element of this reasoning that is flawed: it is not "since" SER and Asterisk are "both" registrars. In this scenario, SER is not acting a UAS; it is not the logical target of the REGISTER request. Therefore, it is not behaving as a "registrar." Only Asterisk is the registrar in that scenario.
There is nothing in RFC 3261 preventing you from fronting a registrar with a proxy and statefully relaying REGISTER requests; in principle, a proxy can forward any request. However, proxies (and UASs) cannot add Record-Route headers to the request, and since REGISTER does not establish a dialog, route sets have no meaning in relation to it anyhow. This means there is no way to establish a pre-determined route set in any scenario ("trapezoid") involving one or more proxies between the registrant and the registrar.
The solution to that problem is Path (RFC 3327). -- Alex Balashov - Principal Evariste Systems LLC 1170 Peachtree Street 12th Floor, Suite 1200 Atlanta, GA 30309 Tel: +1-678-954-0670 Fax: +1-404-961-1892 Web: http://www.evaristesys.com/ _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
