[cisco-voip] g729 is used instead of iLBC

[Alex]

No way iLBC can be used between 7941 and 7942 in the same cluster when region BW is set to 24 kbps - CCM has visibility of both IP phones and knows they have common G.729 codec.
Gateway does not have common G.729 codec with 794x.
Rgds
Alex
  ----- Original Message ----- 
  From: Anthony Kouloglou 
  To: Alex 
  Cc: cisco-voip at puck.nether.net 
  Sent: Tuesday, December 02, 2008 7:26 AM
  Subject: Re: [cisco-voip] g729 is used instead of iLBC


  Hi Alex,
  during call setup, 7942 shows ilbc and 7941 shows g711 as codecs.
  As soon as someone picks up the phone the conversation is in g729.
  So, there is no way to talk in ilbc between 2 regions even if a have transcoders?
  But that why a transcoder is needed; to join 2 devices that cannot support the same codecs.
  And why does the voice gateway uses the transcoder?

  Thanks
  Anthony

  Alex wrote: 
    I'll give it a stab.
    Device A/7941 and Device B/7942 share 2 common codecs: G.711 and G.729a.
    Your region config as described below allows iLBC as MAX codec BW (max BW per call == 24 kbps, see http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/6_0_1/ccmcfg/b02regio.html#wp1055534)
    The transcoder does not get invoked between 2 IP phones in the same cluster if they share a common codec.
    As to why iLBC shows in call stats, I have no idea - it should not as 7941 does not support iLBC.
    Rgds
    Alex
      ----- Original Message ----- 
      From: Anthony Kouloglou 
      To: Jason Burns 
      Cc: cisco-voip at puck.nether.net 
      Sent: Monday, December 01, 2008 2:53 PM
      Subject: [cisco-voip] g729 is used instead of iLBC


      Hi all,
      i really can't understand this behavior:

      Phone A (7941) is in device pool A which has region A. 
      Registered IOS Enhanced Transcoder has device pool A and is configured for iLBC.(It is physically located at site A)
      There is no media resource group or list configured in all the cluster. So all the resources are shared equally upon request i guess.

      Phone B (7942) is in device pool B  which has region B. (another siteB)
      Region A<-> Region B has iLBC configured.
      Hub_none location is configured in device_pool A.
      Location B has 80kbps configured and is lossy configured  versus hub_none.
      Location B is in device pool B

      Phone A can talk with phone B whoever calls the other.
      When A calls B or B calls A before the other answers the call, ilbc is shown in call statistics.
      When the call setup is finished and they talk, the codec on both ends is g729!!! I have nowhere configured g729 in any region!! how is this possible?
      Also, phone B calls through the voice gateway in site A and through PSTN. The codec from phone B to router is iLBC!!
      Also, phone B calls a trunk configured in site A and listens to voice-mail. The call is also iLBC!
      Voice gateway/trunk has the same settings as the phone A (that is: a device pool A and MRGL none.
      So i guess, the transcoder is working fine.

      What am i missing?
      Why can't the two phones talk in ilbc? 7941 can't use the transcoder which is in the same site?

      Thanks
      Anthony





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