Transcoding question

Unanswered Question
Sep 1st, 2008

Hi all, I have a transcoder problem to make a call to a cell-phone. For my CCM 4.1(3)sr7 I have two device pools configured (DP-A and DP-B), two regions and two locations with three 7912 ip phones in the remote region.

I have a Cisco 2801 for conference and trancoder hardware resources, and they are registered in the CCM. When I try to establish a call, the call is drooped and I can see that a transcodig resources is being used but no packets are being received. But when I use G711 in both regions, the call is completed.

What should I check?

Thanks for your help


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Overall Rating: 4 (1 ratings)
Marwan ALshawi Mon, 09/01/2008 - 06:12

r u sure the Xcoding resource enough and configured correctly?

what is the bandwidth between locations in CCM?

als UNcheck The Media Termination Point Required check box on the gateway setting page

good luck

david-lima Mon, 09/01/2008 - 06:22

Thanks for your reply my friend. I have 12 transcoder session and 4 conference session configured in the 2801, and both resources are registered in the CCM.

The MTP is also unchecked in the Gateway.

Before the CCM upgrade (3.3(4) to 4.1(3)), everything was working OK.

Thanks again my friend.


Chris Deren Mon, 09/01/2008 - 06:35

Are you making phone calls between phones only? Or Cisco voice GW? In either scenario you do not need transcoders as the phones can natively negotiate any codec, the GW port can do the same assuming it's in flex mode (default). Please provide more details on your exact call flow path.


david-lima Mon, 09/01/2008 - 06:54

Calls between IP Phones are made without any problem and calls to the PSTN too (Cisco 3640 with two E1). The call to the cell-phone go through and iGATE to saving costs, in the CCM I use this device as h323 GW. The call flow is:

Remote Phone->RT 1750->(WAN)->CCM->RT 3640(E1)->PSTN .....(OK)

Remote Phone->RT 1750->(WAN)->CCM->iGATE->GSM .....(Fail-Call Dropped)



Marwan ALshawi Mon, 09/01/2008 - 07:04

the problem with the IGATE

the first path working ok because the gateway and CCM use the Xcoding

but the second path sounds there is somthing making mismatching and it is obvouse because u said when u use g711 it works

have u tried to define MGRL with xcoding on the igate setting page!!

david-lima Mon, 09/01/2008 - 07:14

Yes I have. The iGATE setting page is in the Default Device Pool, and in the GW configuration page has a MRGL configured, but it only works if I have the SW and HW resources configured. If I assign a MRGL only with HW resources for xcodec and cfb, the calls to cell-phones fails from local and remote sites. I thought that it can be a configuration problem in my resoureces, but I can establish conferences between 4 IP Phones, 2 Local phones (PTSN) and 2 phones from another cluster.

Thanks a lot


Marwan ALshawi Mon, 09/01/2008 - 18:24

what u mean in SW ?do u mean software

by the way

try to check the MTP required and make sure u have MTP resources configured on the hardware so u have to have Xcoding and MTP on the hardware

and assign it to the GW on the setting page

good luck

david-lima Mon, 09/01/2008 - 18:57

Thanks for your reply my friend. I'll try your great advice and I let you know.

Thanks again



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