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Media Bypass Inconsistent RRS feed

  • Question

  • We are using an Audiocodes Mediant 1000 with latest firmware.  Worked with service tech from Audiocodes today.

    Setup TLS on the gateway.  Works fine.  Enabled Media bypass in both the Network Config and the Trunk Configuration.

    Did a Wireshark trace from a workstation making a call.  I can see the media going directly to the gateway.

    Had problems, maybe or maybe not related to Media Bypass.  So I disabled Media Bypass.  Then I could not get it to do Media Bypass after enabling again, restarting all services multiple times...

    The only thing I did not do is reboot the server.

    This is a real problem, because I don't want to just Enable it and wait for it to maybe start trying Media Bypass again, because then I won't be tracing and testing to make sure it works... and for sure catastrophe will happen when I am out of the office!!!

    Any Ideas why I can't get it to start trying Media Bypass again in a repeatable/reliable way?


    -Barry
    Tuesday, December 21, 2010 3:47 AM

Answers

  • Okay I finally figured a way to get Media Bypass going again.  You can't just "restart" all services, and you don't have to stop all servers.  YOu must stop ALL services on the Front-End Server & the Mediation Server AND the only way I could get it back on was to also select "Always bypass" in the network configuration.  After it got started working I could select "Use Sites & Region Configuration" instead of "Always Bypass."

    One more important thing!  The "Lync Server Audio Test Service" takes a while to stop.  You have to wait for that to stop before starting all the other servers/services.

    Now you may be able to do a little bit less than this, but not much.

    I think this is a dumb thing to have to do, given that when you disable Media Bypass it stops trying to do it immediately!!

    But anyway... if somebody else is pulling their hair out, this is a way I was able to get it working.


    -Barry
    • Marked as answer by Barry Adkins Wednesday, December 22, 2010 11:39 PM
    Wednesday, December 22, 2010 11:39 PM

All replies

  • You should use Logging Tool, activate S4 and SIPStack (both with Level All, All Flags). After a test call click "Analyze Log Files" (Resource Kit Tools must be installed) and look at SIP messages between Lync Mediation Server and Gateway - especially in SDP part. You should see if media bypass is tried by exchanging IP addresses of client and gateway. There are also some diagnostic headers displaying information on bypass.

     


    Johann Deutinger | MCTS Exchange 2007/2010 / OCS 2007 | ucblog.deutinger.de
    Tuesday, December 21, 2010 9:57 AM
  • I will admit to some or perhaps a lot of ignorance.  I can usually follow a trace well enough to figure out what is going on.  I did what you suggested and it does not appear that an attempt to hand off the media is made.  Although I can see in many packets that it shows media bypass is supported on the particular device sending the packet.

    After several hours however, Media Bypass will suddenly start working, but when it does the Response Group Service cannot hand off the call to a Response Group Agent.  It makes it very hard to trouble shoot, because I have to disable media bypass so the office can function, and then when I get a chance I enable it, and hope it comes on when I have the time to troubleshoot the problem.

    I am a bit annoyed no Microsoft person has responded to my post on this issue.


    -Barry
    Wednesday, December 22, 2010 8:21 PM
  • Okay I finally figured a way to get Media Bypass going again.  You can't just "restart" all services, and you don't have to stop all servers.  YOu must stop ALL services on the Front-End Server & the Mediation Server AND the only way I could get it back on was to also select "Always bypass" in the network configuration.  After it got started working I could select "Use Sites & Region Configuration" instead of "Always Bypass."

    One more important thing!  The "Lync Server Audio Test Service" takes a while to stop.  You have to wait for that to stop before starting all the other servers/services.

    Now you may be able to do a little bit less than this, but not much.

    I think this is a dumb thing to have to do, given that when you disable Media Bypass it stops trying to do it immediately!!

    But anyway... if somebody else is pulling their hair out, this is a way I was able to get it working.


    -Barry
    • Marked as answer by Barry Adkins Wednesday, December 22, 2010 11:39 PM
    Wednesday, December 22, 2010 11:39 PM
  • HI Barry, I am replying on the of chance you are able to give greater detail on your interaction with Audio codes.

    What configuration changes did you make on your Mediant 1000 as a whole and with regards to TLS?

    I had a client with OCS 2007 R2 and a Mediant 1000 - working without issue; we then have attempted to move the client towards Lync2010 Front end and Colocated Mediation role (virtualised).  I then tried to enable Media Bypass on the Lync 2010 server in Security in Network configuration globally and Trunk Configuration in Trunk rules.

    I then run Logs and there is no interaction between Lync client and the Mediant 1000 direct.

    I was told by Audio codes no configuration was required - this is a Lync2010 Feature.

    Any help would be great,

    Wednesday, February 9, 2011 8:29 AM
  • There is indeed no configuration on gateway side for media bypass. All qualified gatways support that automatically. You must use TLS because by default clients require encrypted mode (SRTP) otherwise RTP would still be relayed by mediation server.

    In your logs you should inspect all messages with SDP and look at the IP addresses there. This is the place where SRTP endpoints are negotiated.


    Johann Deutinger | MCTS Exchange 2007/2010 / OCS 2007 | ucblog.deutinger.de
    Wednesday, February 9, 2011 10:07 AM
  • Is TLS really required between Mediation Server and Gateway for Media Bypass to work?? I've been looking through the latest Lync Planning & Deployment docs, and they never once mention this in the Media Bypass sections.

    Thanks

    Tuesday, March 8, 2011 5:55 AM
  • As I said above clients require encryption (SRTP/TLS) by default. Media bypass means that voice stream is flowing directly between clients and gateway, therefore gateway must be configured for encryption or you change client setting to use TLS/SRTP optionally.
    Johann Deutinger | MCTS Exchange 2007/2010 / OCS 2007 | ucblog.deutinger.de
    • Edited by jwdberlin Tuesday, March 8, 2011 9:49 AM typo
    Tuesday, March 8, 2011 6:52 AM
  • Although I can see in many packets that it shows media bypass is supported on the particular device sending the packet.
    -Barry

    Barry,

    can you give me an example, how the media bypass capability is visible / advertised between a capable-gateway and the Mediation server? Greatly appreciate!

    Thursday, November 10, 2011 2:39 PM