One way audio CIPC

[the-lebowski]

Hi

New install with SIP trunk on 2911 and using ASA for RA VPN Client.  I can register the softphone fine while connected via the VPN client, can make calls and can hear the end party but they cannot hear me.  Using anyconnect client (windows 7 no firewall) to reach the call manager and for the life of me cannot figure out what the issue is.  I can ping the call manager from the VPN client and vice cersar, I tried a tunnel-all profile and the behavior still exists.  It makes me believe the the traffic is being blocked but I can't for the life of me figure out where or why. 

Any ideas?

[daniel.bloom]

Are you able to ping an IP phones IP address from the VPN? Is the asa the only firewall in the network?

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[daniel.bloom]

Are the calls that experience one way audio with internal phones or external phones over the sip trunk?

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[m.pratt]

I just ran into a similar issue with SCCP CIPC. Turned out to be a faulty headset on the users end.

Just thought I would mention it.

[the-lebowski]

Issue is happening to another user as well so its not just local to me.  I aslo tested using my built mac speakers and mic and the issue persisted.  Thanks though.

[the-lebowski]

Daniel

1. I can ping both directions, from LAN to VPN client and VPN client to LAN (includes CUCM and the 2911 where the SIP trunk terminates).  I can ping the only desk phone over there from the VPN client and such.  So IP connectivity appears to be there.   The only thing I cannot ping is the sip trunk interface on the 2911 (its a public IP) from the VPN client.  But I can ping that interface from the LAN without issue.   When I attempt to ping it from the VPN client I get Asymetric NAT rules in the logs and not sure how to solve that.  

2. The only calls I can make are from a softphone via the VPN client (this is a remote install).   So at this point this problem exists from calling external phones over the sip trunk. 

[daniel.bloom]

Can you run the following debugs on the 2911 router and make another test call.

debug ccsip messages

debug voip ccapi inout

[Dennis Mink · Accepted solution]

9 out of 10 times issues like this are either routing or codec related (in my experience).

If I understand you correctly your 2911 is doing SIP Trunk to an external SIP provider?

Pinging call manager, doesnt prove a lot as it does not sit in the RTP path.

you will need to be able to connect to the 2911's SIP trunk's IP address from your VPN client, as you will set up an RTP stream to that IP address when making an external call.

also start by temporarily opening up your FW to everything from the VPN client for testing purposes, just to simplify the equation.

also check your codec settings


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[the-lebowski]

minkdennis got it right, alhtough I fixed it berfore I saw your reply. 

It was a simple route back to the sip trunk interface from the inside interface of the ASA.  Once I added the route I was able to get two way audio.  I assume since the sip trunk has a public IP the ASA was routing traffic from the client out to the internet instead of towards the 2911. 

The only lingering issue is I cannot ping the sip trunk from the VPN client but I only assume its a nat'ing issue which I havent been able to solve.   I can ping the vpn client from the sip trunk interface on the 2911.