Multiple Inter Cluster Trunks

[Carl Ratcliffe]

Hi Support Community

I have 3 CUCM clusters each connected to the other for call routing via Inter Cluster Trunks, this has always been in place and calls have been routing between the clusters from day 1.

I am looking at implementing TEHO and will be gradually adding to this configuration over time. I need some advise on if it is possible and / or recomended to have additional Inter Cluster Trunks that will be exact replicas of the existing inter cluster trunks with the only difference being the CSS assigned to them for inbound calls.

So the overall aim would be phone to phone traffic over the existing inter cluster trunks as it does now  and TEHO traffic over the new intercluster trunk. My reason for doing this would be simply provide a logical seperation on the system for troublshooting and so that i can apply seperate inbound CSS.

Thanks, Carl

[Chris Deren]

No, this makes no sense, in fact CSS on trunk is only applicable for incoming calls, and you will have no control which trunk is hit if they point to the same IP addresses. Use the same trunk for TEHO and inter-office routing.

depending on your version of CUCM you may also want to conisder replacing H323 ICT with SIP trunks.  SRND does a very good job describing what you are looking for.

HTH,

Chris

[Carl Ratcliffe]

Hi Chris

Thanks for the response.

Im not sure what you mean by having no control over what trunk is hit ? I will have full control over what trunk is used because this is standard call routing, my device / translation pattern will have a CSS assigned to it and this CSS will have partitions, paritions are assigned to my route patterns which then sends onto a route list and then the route group which contains the trunk so surely if i hit a specified pattern assigned in a particular parition it will route to the trunk that is specified in this route group ?

Thanks, Carl

[Carl Ratcliffe]

Hi Chris

Just to be clear, the reason for doing this is 1 for troubleshooting so we can clearly see TEHO calls separated in things like Dialled Number Analyser and 2 so that we can apply different inbound CSS.

Thanks, Carl

[Chris Deren]

If you have 2 trunks pointing to the same destination, then on the other side you can not control which trunk the call arrives on, hence having different CSS will cause problems.  Remember when you build ICT it is just IP connection, and you dont link them on the other side in any way.

HTH,

Chris

[Carl Ratcliffe]

Thanks Chris, you have answered my question, it isn't really possible to do this.

So the bottom line is between 2 clusters and using the same ip addresses in the trunk you can have only 1 inter cluster trunk to control all traffic and therefore you can have only 1 css to control this traffic?


Sent from Cisco Technical Support Android App

[Chris Deren]

Correct.

Chris

[Suresh Subramanian]

How about having SIP trunk between the clusters for TEHO traffic? With that, we can have seperate CSS and Routing.

[Ayodeji Okanlawon]

I agree with Chris on this..First of all I dont even think you can configure multiple trunks to the same destination. From memory, CUCM will reject it..

Second there is no logical reason why you want to have two different turnk types to the same destination. If you want to use SIP use SIP for everything and if its ICT, then use it for everything. Like Chris suggested build your TEHO on your existing trunks...Clean and Tidy.

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