Inter-Cluster Trunk - CODEC Query

[drbabbers]

All,

I have setup an ICT between 2 CUCM clusters - Site A + Site B. Site A uses G.711 and Site B uses G.729.

If Site A calls Site B, during the SIP or SCCP call setup Im guessing there will be a CODEC mismatch? If Site B add a Transcoder resource via MRG to the ICT, will this transcode from G.729 to G.711? Also vice versa, if a calls originates from Site B towards Site A, Site A will require a Transcoder resource?

Thanks!

D

[zdesignstudio]

•Outbound intercluster calls will use an MTP/transcoding resource from the Cisco CallManager from which the call originates.

•Inbound intercluster call will use the MTP/resource from the Cisco CallManager that terminates the inbound intercluster trunk.

•Allocate additional DSP MTP/transcoding resources to Cisco CallManagers terminating intercluster trunks.

•For compressed callers, you can accurately provision the MTP transcoding resources.

Please rate useful posts and mark answers as "correct" if applicable.

[drbabbers]

Thank you for the overview, this is now a lot clearer! :)

D

[Vivek Batra]

Do you really need transcoder for this reason? Codec selection is controlled through region. Let site A uses G711 and site B uses G729 for internal calls. Have a region for ICT and control the codec to be used between two sites. If it's WAN, you probably would like to use G729 and you don't need to use transcoder at all.

- Vivek

[drbabbers]

Thank you for your reply. I have never actually setup an ICT in a production network before so this is new to me. I do however understand the Region concept, that part makes sense. :) I didnt realise you could use Regions between different clusters connected via an ICT. :)

D

[Vivek Batra]

You would eventually need region for any type of call whether it's internal, external etc etc. Region settings will always be checked as per device pool configured between calling and called party because you always need codec irrespective of the type of call. 

- Vivek

[drbabbers]

Hi Vivek,

Can you please elaborate on this? So if I setup the ICT in Site A and associate it with a Device Pool. The Device Pool then is associated with a Region. (Site A already has relationships with all other Regions in the Site A cluster)

How will Site A know anything about the Regions available in Site B? Site B is a seperate cluster. Im struggling to understand this part.

Or do I setup a new Device Pool for Site A, attach it to the ICT and setup a Region for the new Device Pool with G.729 as the only available CODEC?

D

[Vivek Batra]

Or do I setup a new Device Pool for Site A, attach it to the ICT and setup a Region for the new Device Pool with G.729 as the only available CODEC?

You understood it right. You need to have new device pool and region assigned to ICT in SiteA. Let say you want to use G729, let's have 8 Kbps bandwidth set between phones and ICT region in Site A. That's it.

Although you don't need to have same configuration in siteB because SiteA is configured to use 8 Kbps bandwidth but I suggest to have clean configuration and have the same thing configured in SiteB too.

- Vivek

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asdf

[drbabbers]

Thanks Vivek all good stuff and understood.

However... Do I still have the option is Transcoding with an ICT?

The problem I have is the endpoints in Site A are currently attached to a Region using G.711 only. I dont really want to be creating a new DP just for these endpoints and the ICT.. Is Transcoding a practical option?

D

[Vivek Batra · Accepted solution]

Hi there,

Transcoders are invoked only in case of codec mismatch and usually required with applications like MoH, CUC and UCCX in centrailzied deployment. In your case, there is no reason to invoke transcoder when two end points can agree on the same codec. 

Let phones in SiteA having intra-region relationship set to use G711. We don't need to change anything at this end. We are just suggesting to have inter-region relation set for G729.

Ideally you should have separate device pool and region for all type of trunks. This will give you maximum flexibility and ease of troublshooting. 

Transcoder means money. You might have spent good amount of money in transcoders. Why to waste it just to get away from configuring region and device pool. IMO, transcoding is not a practical situation in your scenerio.

- Vivek

Please rate useful posts.

[drbabbers]

Vivek,

Thank you for all your help! Learning everyday. :)

D

[Vivek Batra]

Hi...

Glad to know I could help you.

-Vivek

[drbabbers]

Thanks Vivek! Also one last thing please... How about if the calls from Site A are transferred across to Site B using a CCX script? I have a CCX trigger that will end up answering the inbound calls for Site A and then via the Menu, the caller has the option to press 2 to be transferred to Site B. Is this just a case of the CTI Route Point/corresponding Device Pool having the Region relationship also? D

[Vivek Batra]

No issues, happy to help :)

I don't have much exposue to contact center but I try to put my words here what I know.

CTI Route Ports region comes into picutre for codec selection only when media is streamed from UCCX. Once call has been transfered to Site B, region of originating trunk and terminating trunk will be used for codec selection.

Let say in Site A, you've incoming call on Trunk1 which is routed to UCCX. Codec used here will be as per region settings between trunk1 and CTI port handling that call. Now if call is being transferred to site B using trunk2, region settings between trunk1 and trunk2 will determine the codec to be used.

- Vivek

Please rate useful posts.

[drbabbers]

Would anyone be able to list the high level steps required to achieve this?

• Setup the ICT with supporting Route Patterns/Lists/Groups
• Associate to a DP
• Setup a new Region for G.729 calling
• Associate Region to DP

What about the endpoints themselves?

D