Force SIP/RTP out second WAN connection

Unanswered Question
Sep 24th, 2009

Two Internet connections to UC520.  1 for data, second for voice.  Voice using SIP trunking via the Internet.  Is there a way to force the SIP and RTP traffic out the second connection or to source if from the interface connected to the second connection?

A couple specific IP routes are somewhat effective to establish calls, but the media streams are all over the place as far as IP's are concerned, so static routes are out.

I've tried local policy routing, but haven't been able to figure out a combination of ACLs, etc. that match the traffic I need to force.

Any ideas?


I have this problem too.
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Maulik Shah Thu, 09/24/2009 - 21:34

You can bind the SIP / RTP traffic on the UC500 to a specific WAN interface as below:

voice  service voip


    bind all source-interface FastEthernet 0/0  (interface must be the one with the IP address configured on it)

This may help in terms of what IP the UC500 uses to send SIP / RTP packets (helps for the return path). However the UC500 would depend on its routing table for the best route to the IP address on the far end for SIP / RTP packets. If these are not a specific subnet per what you describe you could try local policy routing as below but please ensure you test this and ensure no other flows break:

Make sure your access lists deny SIP traffic to CUE so that traffic is not policy routed.

Note if you use the bind CLI - make sure you change the SIP gateway on CUE GUI at Configure > Unified CallManager Express to the IP address of the interface used in the bind CLI.


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