Non-gateway Intercluster Trunk CCM 4.1(3)

Unanswered Question
Feb 26th, 2007

I just setup a non-gateway intercluster trunk between my company and a client of ours. I then setup a translation pattern for the called number 9000 to route to my extension. The client setup a route pattern to send any calls to 9000 over the trunk. If the client dials 9000, the call will ring into my extension. From my phone, I see the name of the client calling and the extension 9000. However, when I pickup the line, there is no audio on either side. It still shows us as connected. To my knowledge, the voice subnets on each side were opened up to each other.

1. Has anyone seen this or know what the problem is?

2. How can I go about testing to see if this is my side or the client's? Are there any trace logs that will tell me what end is disconnecting or not working properly?

Any assistance provided would be greatly appreciated. Thank you in advance!

I have this problem too.
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mchandak Tue, 02/27/2007 - 07:16

Can u ping the phones on the other cluster from the CallManagers ??

walteryork Tue, 02/27/2007 - 13:49

Yes, if I can clarify a little further, I can place and receive calls but if the client tries to place a call to one of my IPCC CTI Ports, it disconnects immediately...

astinus Tue, 02/27/2007 - 14:40

Sounds like a possible codec mismatch. The phones can negotiate another codec, the CTI ports are stuck at what they are set for during installation (on Express at least). If it can't access a transcoder, you get the symptoms you're running into.

You could verify by creating a new Device Pool that's a copy of your existing one, except that it has a Region which forces all calls to either G.711 or G.729 (based on which codec your IPCC is installed at). If it works ok with this, your problem's the codec and you need to get a transcoder setup and available for the calls.

Hope this helps,

Jim

walteryork Wed, 02/28/2007 - 21:28

Jim,

You were completely correct. We are using g711 and the client is using g729. Our IPCC server only supports g711 while the IP phones support both. That explains it working for the phones but not the IPCC calls.

The next fun part is setting up a transcoder or asking the client if they will convert back to g711. But with g729 using almost 8 times less bandwidth than g711, it would be hard to convince them to change.

Is the transcoder builtin to the IOS on certain routers or does this require a card?

astinus Thu, 03/01/2007 - 06:14

Walter,

The good part about the transcoder is that it will not require anyone to change what they're running. If the call is coming from your customer as G.729 and you need it to be G.711 on your end, you just need to deploy transcoding resources on your side.

The call will still come from them as G.729, but once it enters your network and attempts to hit the CTI ports, the transcoder will be invoked then. It will be transcoded to G.711 just for those calls to the CTI ports and will not effect anything else.

As to the mechanics of getting the transcoder functional, I would refer you to the link that Sankar provided.

Good luck,

Jim

levinsky Thu, 03/01/2007 - 06:26

Hi all,

I have exactly the same problem. I am positive its a codec issue but can't see any problem with the config and I have transcoders.

I have CCM cluster 1 with IPCC Express using G711. CCM cluster 1 has a gatekeeper controller h225 trunk out to CCM cluster 2 and CCM cluster 3. Calls come across the trunk as G729 from both CCM clusters 2 & 3. Calls from CCM cluster 2 are transcoded fine to G711 and they can call IPCC Express. Calls from CCM cluster 3 coming in the same trunk don't get transcoded (unless we activate an MTP which forces all calls over the trunk to G711 - not good so I removed the MTP).

Any reason why calls from one cluster would get transcoded but not from the other when they arrive in the same trunk controlled by the same gatekeeper?

Thanks,

Ken.

walteryork Thu, 03/01/2007 - 12:26

Ok...

-I created a new device pool and region and associated them to the intercluster trunk.

-Setup G.729 on the region assigned to the intercluster trunk.

-Went to transcoder under services, added transcoder type, "Cisco IOS Media Termination Point" and entered the voice side interface mac address of the router and selected the intercluster trunk device pool.

Registration shows as unknown but that is fine because transcoder isn't configured on the router.

We are at CallManager ver. 4.1(3)sr3c which satisfies that requirement. Our router is a 2821 series router running 12.3(11)T6 which satisfies IOS requirements. I will need to have at most 12 active sessions just for transcoding. Being very new to router configurations, what do I need to enter into the router to configure transcoding. I have seen the link that Sankar provided and that does have sample configs but would be good to get specific advice... Again, thank you for your assistance especially Jim and Sankar.

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