CUCM Globalisation and Resiliency

[Carl Ratcliffe]

Hi Support Community

First of all i havent got a technical issue as such i was more interested proffesional opinions on the way they configure Globalisation and Resiliency for certain sceanrios :

Scenario 1 Globalisation

Currently Globalisation is implemented so Outbound calls have the calling and called number globalised at the ingress translation pattern, they are then localised again at the egress gateway using transformation masks. Inbound Calling numbers are globalised at the ingress using Incoming Calling Party settings and localised at the egress using transformation patterns in the device pool settings.

My query is, when using MGCP gateways you only get Incoming Calling Party settings on the gateway and not also Incoming Called Party settings as you do with a H323 therefore you cannot globalise at the egress. So my question is were do you globalise the incoming Called number on an MGCP gateway ? The only way i can see of doing this is to allow the gateway to send the called number as presented by the telco to a translation pattern, this could then globalise however i cannot see the point in globalising here as technically its not the ingress location, plus you would have to immediatley localise again with another translation pattern to the internal extension number of the phone.

Scenario 2 Resiliency

I have multiple clusters of CUCM using Extension Mobility, Inter-Cluster trunks are used for Inter Cluster communication and resliency is in place so that internal calls first route over the trunk then secondly over the PSTN. This has always worked fine.

Within a single cluster there are multiple sites geographically separated so for example UK and the USA. All sites also use SRST so in the event a site cant see the CUCM servers SRST fallback will take place and numbers are still accesible for these sites if you dial the full DDI. Im interested to know how people implement the dial plan so that a phone in the same cluster lets say the London which is registered to CUCM can phone a New York phone that is now registered to SRST. Bare in mind Extension Mobility is used so Cisco recomend not to use Call Forward Un-Registered. Currently in this scenario calls just go to Voicemail, i cannot see away of using anything like Route Lists for something like this.

Thanks, Carl Ratcliffe

[Chris Deren]

1. you would do it with translation and/or transformation patterns, however I would recommend ditching MGCP in place of SIP especially for globalized dial plans

2. Forward to un-registered is the only option here, simply setup that destination as the full DID.

HTH,

Chris

[Carl Ratcliffe]

Hi Chris

Thanks for your response.

For point 1, i agree, i dont like MGCP due to its limitations in digit manipulation and removing them is defintley something on the cards although there are around 30 gateways using MGCP so not a quick fix. From what i can see though SIP has the same limitations for Globalising the inbound called number as it only has incoming Calling party settings and not Called. I did Globalise an MGCP incoming Called number  at the Translation Pattern level and it works fine but as soon as a Globalise here with 1 translation pattern i have to immedialtey localise again with another translation pattern to the extension number. Becasue this isnt really ingress thats why i was querying if it was correct.

Point 2 works fine if SRST is actually invoked however most of the time the unregistered number is just due to somebody logging out of extension mobility so call forward unregistered isnt really an option becasue it will cause a loop. I can limit the number of hops but not sure if that is a recomended way of doing it. Plus when users do log out of extension mobility it still needs to go to voicemail. 

Thanks, Carl

[Chris Deren]

Looking at my 10.0 CUCM I see incoming called party settings on a SIP trunk, not sure if it is there in 9.1. Alternatively simply normalize on the SIP GW.

Agree on point 2, what is your dial plan defined as, is it e164, how do people call the users?

Chris

[Carl Ratcliffe]

Hi Chris

We are hoping to move to version 10 once we get a .1 release which is probably going to be a good few months off yet. We are currently using 8.6.2.

Internally we use 4 digit extensions and 3 digit site codes. Any Off Net calls have Calling and Called number Globalised except in the case of the scenario i mentioned were we dont currently Globalise inbound Called numbers at the MGCP gateway.

Thanks, Carl Ratcliffe

[Chris Deren]

Right, there would be no other way to automatically reroute the calls to DIDs with the globalized translations yet keep them to go to voicemail under unregistered condition short of telling people to dial the numbers differently (ie. different site prefix).

HTH, please rate all useful posts!

Chris

[Carl Ratcliffe]

Hi Chris

Thanks for your response, i suspected as much in version 8.X but i was hoping that versions 9.X or 10.X would address this limitation.

Thanks, Carl Ratcliffe