locked
Mobile client has no audio after 5 seconds RRS feed

  • Question

  • We have found that when a user is making a call from their SfB mobile client (Android or iOS) that if they make a call to the PABX or the PSTN that the call is nailed up, but the audio is lost after 5 or 6 seconds. If the same user makes a SfB call to an internal SfB desktop or another SfB mobile client, the call and audio stays up the entire time. If a user makes a call from a SfB client on a PC from the Internet in the same way, the audio stays up the entire time to a call on the PABX or the PSTN.

    We have taken traces on the firewall and cannot find that any ports are being blocked to the mobile clients to account for the loss of audio. Has anyone else run into this?

    Friday, August 5, 2016 3:43 PM

All replies

  • Same issue was discussed recently in this thread looks some misconfiguration over Reverseproxy or Loadbalancer. reverify the configuration.

    https://social.technet.microsoft.com/Forums/office/en-US/491576ed-9481-4e67-8e64-2d29809308f1/lync-2013-mobile-clients-audiovideo-call-getting-failed-on-3g4g-network?forum=lyncvoice



    Regards, Rajukb | MCSE (Communication ), MCSA (o365) ,Certified "Lync server 2013 depth support engineer"| This posting is providedwith no warranties and confers no rights. If my reply answers your question please mark as answer/helpful if its helpful.

    Friday, August 5, 2016 5:52 PM
  • Yes, I had seen that same thread. However, the issue happens not only when the mobile client in on the 3G/4G network, but also when it is on a Wi-Fi network. 

    Taking a closer look at the firewall traces, it appears that the audio port on the Cisco side was set to TCP:65535, but the firewall rule is to only allow 50000 to 5999 to the AV Edge interface. This was causing the audio packets to be dropped.

    Is there a way that I can change the media port range to only that range on the system or is it better to allow the full ephemeral port range on the firewall to the AV Edge interface?

    Friday, August 5, 2016 6:52 PM
  • Yes you can change the allowed port range, first of all try to chance it from Cisco which is very easy to do so.

    if Cisco is not allowing then try to change from Lync side

    https://technet.microsoft.com/en-us/library/jj204760(v=ocs.15).aspx


    Regards, Rajukb | MCSE (Communication ), MCSA (o365) ,Certified "Lync server 2013 depth support engineer"| This posting is providedwith no warranties and confers no rights. If my reply answers your question please mark as answer/helpful if its helpful.

    Friday, August 5, 2016 6:59 PM
  • Thanks for the link. I have a request in to modify the TCP/UDP range on the firewall before making any SfB changes for now.

    My confusion now lies with why this happened in the first place. When the mobile client makes a call, it should be nailed up to the external interface of the Edge server in the 50,000 to 59,999 range and the connection from the Cisco IP phone should be to the inside interface of the Edge server on its RTP port. Why is the Edge passing the RTP traffic from the Cisco phone instead of just relaying it to the external interface on the established RTP port to the mobile clilent?

    Friday, August 5, 2016 8:50 PM
  • More traces have shown that the media between the Cisco phone and the Skype environment is nailed up between the phone and one of the Front End servers. 


    The question now is: If the firewall is only allowing TCP/UDP ports to the Edge servers' external interface from 50000 to 59999, as per Microsoft's instructions, why is the media being established over a port outside of that range?

    Tuesday, August 9, 2016 2:48 PM