[reSIProcate] Routing of signalling via proxy - opinions?

[Daniel Pocock]

Steven Coule wrote:

>Using a prototype with the Radvision stack, the Asterisk was ignoring
>the maddr parameter which should (in my belief of the theory at least)
>cause calls from the Asterisk to be routed via my Proxy. It didn't work,
>and the maddr parameter seemed to be deliberately ignored in the code -
>it could be patched, but I'm looking for the most compatible solution of
>inserting my monitoring/call control solution into a SIP environment.
>
> 
>
>I'm not sure if we can configure an outbound proxy for SIP phones
>registered to the Asterisk - I didn't think this was the case but will
>take another look.
>
>  
>
I believe outbound proxy is only recently added to Asterisk or not fully 
implemented in some versions.  Older versions didn't have this at all.  
You would have to look at the source code to determine how it decides 
which calls/SIP messages go through the outbound proxy.

> 
>
>The Route header is worth a try. I noted in 3261 that the Record-Route
>header is to be deliberately ignored if present in a REGISTER, but that
>doesn't apply to a Route header.  I guess the key here is whether the
>Asterisk (or other) server will store the Route present in the REGISTER
>request and use it to route calls to the UA's via my Proxy.
>
> 
>
>You mention using a Route header embedded in the URI ... from reading
>the specs, it looks like this could work.  The Path Extension RFC 3327
>header also seems like another option to look into - from reading the
>spec it perhaps looks most likely to work.
>
> 
>
>I'll take a look at repro and Asterisk to see whether the Path is
>supported ... 
>
> 
>
>Thanks for your help ..
>
>
>Steve
>
> 
>
>________________________________
>
>From: Scott Godin [mailto:slgodin at icescape.com] 
>Sent: 16 March 2006 14:59
>To: Steven Coule; resiprocate-devel at list.sipfoundry.org
>Subject: RE: [reSIProcate] Routing of signalling via proxy - opinions?
>
> 
>
>Record-route will only help for messages that go through your proxy - if
>the INVITE is not even hitting your proxy, then you will need some other
>mechanism to tell Asterick to send all requests through you.  I don't
>know asterick at all but maybe you can configure your proxy as an
>outbound proxy on asterick?  So that it will route all requests through
>you first.
>
> 
>
>Or...I'm not 100% sure if this is possible or not - but you could try
>adding an embedded Route header to the Contact Uri of Registrations that
>pass through you.
>
> 
>
>Scott
>
> 
>
>________________________________
>
>From: Steven Coule [mailto:Steven.Coule at envox.com] 
>Sent: Thursday, March 16, 2006 5:25 AM
>To: Scott Godin; resiprocate-devel at list.sipfoundry.org
>Subject: RE: [reSIProcate] Routing of signalling via proxy - opinions?
>
>I wasn't intending my proxy to be the registrar, merely to route the
>REGISTER requests to the registrar in addition to the normal proxying
>behaviour of the call signalling. 
>
> 
>
>As an example scenario, I want to sit my proxy logically between an
>Asterisk PBX (registrar) and the SIP phones it uses so that all calls
>can be monitored using my proxy.
>
> 
>
>The tricky bit seems to be forcing the Asterisk to route calls to the
>SIP phones via my proxy. It appears to ignore the maddr parameter and
>send the INVITEs directly to the phones. Do you think Record-Route will
>solve this?   
>
> 
>
>Thanks for the tip about repro, I've downloaded it and am taking a look.
>
>
>Steve
>
> 
>
>________________________________
>
>From: Scott Godin [mailto:slgodin at icescape.com] 
>Sent: 13 March 2006 18:43
>To: Steven Coule; resiprocate-devel at list.sipfoundry.org
>Subject: RE: [reSIProcate] Routing of signalling via proxy - opinions?
>
> 
>
>If the UA's register with your proxy and are only reachable via their
>AOR - then using Record-Routing on the proxy is the way to go.  
>
> 
>
>You may want to take a look at repro - it is a proxy built ontop of
>resiprocate.  Repro already supports record routing - you could just
>extend repro to add your monitoring code.
>
> 
>
>Scott
>
> 
>
>________________________________
>
>From: resiprocate-devel-bounces at list.sipfoundry.org
>[mailto:resiprocate-devel-bounces at list.sipfoundry.org] On Behalf Of
>Steven Coule
>Sent: Monday, March 13, 2006 12:32 PM
>To: resiprocate-devel at list.sipfoundry.org
>Subject: [reSIProcate] Routing of signalling via proxy - opinions?
>
>I am developing a SIP proxy to monitor SIP call signalling using
>reciprocate and need to force all call signalling traffic via my proxy
>to maintain an accurate call state model.
>
> 
>
>For outbound calls from a UA, the UA can be pointed towards the proxy,
>so that is straightforward. For inbound calls to any UA that I need to
>monitor using my proxy, there needs to be some method for forcing call
>signalling to my proxy rather than directly to the UA. For example, my
>proxy could sit logically between an Asterisk PBX and a UA for that PBX,
>or between a E1->SIP gateway and an array of UA's.
>
> 
>
>As far as I understand, there are a couple of approaches I can use to
>achieve this ..
>
> 
>
>1)       Use the maddr= parameter. By forcing the UA to register with my
>proxy, I can manipulate the REGISTER by adding the maddr= parameter
>before forwarding the REGISTER to the real registrar. In theory at
>least, this should force the inbound calls to be routed via my proxy by
>the Asterisk / SIP server.
>
>2)       Using the RFC3581 mechanism for NAT traversal appears to
>provide a method of forcing a call signalling path via a specific proxy
>using the Record-Route and rport= parameter. 
>
> 
>
>Have I missed anything? Which method is preferred?
>
>
>Thanks,
>
> 
>
>Steve
>
>
>  
>
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>
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