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  • Issues with two different 3rd Party SIP devices calling each other

    We have two different types of 3rd party SIP devices that we have integrated with our ShoreTel Connect system (build 21.82). One is a cisco SPA112 ATA and the other is a dispatch console system. They've been integrated for a while and we haven't seen any issues with calling on either. Recently it was reported that the one cannot call the extension of the other. From the dispatch console side it rings the Cisco ATA but when the call is answered it drops. From the Cisco ATA side the call does not ring the dispatch console on the remote end but instead gets an AA recording "Sorry that extension cannot be reached at this time..."

    These are both using the default 'System' SIP profile. At first i thought it may be a codec problem, possibly a mismatch or something. I don't see the call show up in the TMSNCC log.

    Any thoughts?

  • #2
    Do you see those devices registered on the system? Have you tried just restarting the devices to see if that clears the issue?


    • #3
      Did this ever work before? What have you already tried to resolve the behavior? Have you done any testing with regular users and extensions in both directions? Do these devices exist on the same lan?
      Lance Paddock
      BTX | Business Telephone eXchange
      1(800) 289-0299


      • #4
        Also TMSNCC will have limited knowledge of the internals of a 3rd party SIP call because those phones will not report to it, packet captures and then call analysis with wireshark's voip module works well though and you should be able to compare a good call with a failed call and see what is going wrong.


        • #5
          bhaikalis - The devices are registered and assigned to the user/extension. I have also tried restarting both devices. I've been able to replicate the issue by standing up a test extension with one of each device.

          Lance - To my knowledge this likely never worked. The Cisco ATA's are somewhat new to our setup and calls between the two devices would be infrequent. I've been able to successfully test with both devices individually calling to and from ShoreTel phones, no issues. The dispatch consoles are isolated on their own VLAN however there is nothing between the two that would prevent the traffic from flowing (also the Cisco ATA in the case of my test is on the same VLAN as the ShoreTel phones I'm able to test successfully with.

          blanning - Thanks for the info regarding the TMSNCC log, I'll grab a packet capture and look into it.


          • #6
            I was able to resolve this after seeing the packet capture. The dispatch console was rejecting the call with SIP 488 response:Not Acceptable Here. As it turns out the vendor for the dispatch console has the RTP Packet Size or ptime setting hard coded to 20ms. The Cisco ATA was set to 30ms. Changing the Cisco to 20ms. resolved the issue and the calls are able to connect now.