7 Jul
2010
7 Jul
'10
1:47 p.m.
On 07/07/2010 03:37 AM, rupert.organ(a)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
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Web: http://www.evaristesys.com/