Legacy PBX and CUCM 8.5 dial plan integration

[dlorren01]

We have a client with a old PBX who we are migrating to a CUCM 8.5 and they would like to keep the ability to dial 5 digits between the old PBX and the CUCM 8.5. They are going to have to put in indiviual translation on the old PBX so the system will know that it has been migrated to the new CUCM, the issue is how do we setup on the CUCM so that it will know if the number does not exist on the CUCM to route back across to the old PBX?

[josepaulopetry]

Create a route pattern with five digits (XXXXX) and points it to a route to the old PABX

but take care with route loops.. for example if a number does not exists on OLD PABX and CUCM

[dlorren01]

The issue is that they will have a mix of the DID ranges between the old PBX and the new CUCM system. For example they have 5558880000 to 5558889999 for DID range, any of those numbers in that range could exist between either old or new setup.

[Chris Deren]

That's exactly why only one side can have wildcard match to point to the other side.  I just did a very similar deployment and basically Avaya PBX was configured with explicit matches to point to CUCM extensions. CUCM had wildcard match 5XXXX to point to Avaya, but you can make it the other way where PBX would have wild card match and CUCM would have explict matches for each extension or extension range, i.e. 5011X, 50224, etc. The challenge here is to maintain it, so if DN is created or moved on one side config needs to be adjusted properly.

Chris

[josepaulopetry]

i did a similar depoloyment too in the exact way Chris did

[Chris Deren]

First of all use QSIG to prevent call tromboning.

Second of all your Route Patterns will need to be explicit and include only extensions that are defined on the PBX, basically only one of the sides should have "default" route back to the other side.

HTH,

Chris