Voxitas SIP trunk and UC540

[bfriend]

I'm partly through configuring a UC540 with a SIP trunk provided by Voxitas. I set it up as a Generic provider with the only setting being the destination IP address.  I was able to make a test call out this afternoon, but there were two problems. One, I could not hear anything on the either end, and two, once I hung up the handset the receiving end continued to receive calls one after another. Has anyone here been able to configure a SIP trunk using Voxitas? Can anyone offer any suggestions?

Many thanks

[oni.somroy]

Hi,

If there's no audio on either side, but the call connects, it's not a SIP issue; it's an RTP issue. SIP is signaling and RTP carrys the payload (voice). Once SIP finishes connecting two parties, SIP's job is done and RTP takes over to transport the audio. SIP tells the two SIP devices (aka User-Agents) what IP ports the audio will be transmitted/received on and what kind of audio will be transmitted (codecs). For whatever reason, the two devices aren't receiving audio via the RTP stream, so maybe something like a firewall is blocking it or there's a codec negotiation issue. Do you have a firwall or ALG between the UC540 and your internet connection? Maybe there's a T1 NATting router, etc.?

I've never used Voxitas specifically, but according a document I found while googling, they need the SIP Registrar Server address as well as the username/password for the trunk and the DIDs on that trunk. Supposedly they provide their own DNS server too, so I would say use their DNS server when configuring CCA's SIP Trunk setup screen. Just wanted to make sure those were all in there--if that is indeed what they require--before proceeding further.

Hope that helps.

-Oni

[bfriend]

Oni,

Can you provide me to a link to the document you found regarding Voxitas settings?

Thanks!

[Nathan Compton]

There is no document on how to configure Voxitas for UC500, because they are not a verified service provider.  Are you able to send and receive calls?  From your description, it seems you only have an audio issue.

regards,

Adam Compton

[mtempro · Accepted solution]

Hello,

Good suggestions from SomRoy.  With console/monitor logging you'll be able to see the ip addresses and port numbers which are being denied by access-list 104 on the UC540 (assuming that the UC is the only firewall connected device).  Debug ccsip messages will also reveal any additional ip address which may need to be added to your firewall.  When configuring sip trunks CCA also has a tab which says advance options which allow you to add additional servers from your sip provider.  CCA automatically adds the primary server to the access-list with the necessary ports numbers, any additional servers you need to add under advance options, but I would first verify with my SP which ip addresses I need to allow.

You can also look at your show run and verify that you have these ports opened.

  permit udp any any range 16384 32767    

  permit udp any range 16384 32767 any

I'm not familiar with that SP and I won't be in the office for another 14hours otherwise I'd asked to connect using your credentials and see if I have the same results.  However, you can contact SBSC at anytime and have them perform some troubleshooting.

Regards,

Marvin

[bryan.neese]

Give Voxitas support a call.  I have setup a couple UC540's with their service.  What is happening is that the UC540 is sending a random port 16284 to 32767 to use for RTP, after the SIP signaling is complete.  Both Marvin and Oni are correct on each of their points.  What is happening is Voxitas is sending their response back across the same port that the UC540 is sending the connection, but the 540 is not looking for it on that port, but another port.  Voxitas will have to change on their end that they acknowledge and trust all traffic from your IP address, this should solve both issue.