Single expressway for different clusters

[Ahmed habib]

I need assistant as I want to deploy single expressway MRA for 2 different UC clusters connected over intercluster trunks

What are the restrictions ?

Should the internal domain be identical on both clusters

Should the external domain be identical on both clusters

Should users on different cluster be able to chat each other

Can u provide me with a guide illustrate these points as i found only guide with configuration of same domain internal and external

[Anurag Srivastava1]

Hello Ahmed,

Yes this is possible to configure single pair of expressway with multiple CUCM clusters.

This is also mentioned in MRA deployment guide under " Multiple Clustered Network Elements"

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-11/Mobile-Remote-Access-via-Expressway-Deployment-Guide-X8-11-4.pdf

The things to be noted that-

-both CUCM cluster publishers you need to add on expressway C

- both cluster should be in same domain.

- You need to assign home cluster for users under end user config 

- most important Inter cluster lookup service should be enabled, please see the below link for reference-

https://community.cisco.com/t5/collaboration-voice-and-video/cucm-intercluster-lookup-service-ils-configuration-guide-based/ba-p/3358335

Thanks

Please rate if it is helpful....

[Ahmed habib]

@Anurag Srivastava1  Thanks for your Reply

Regarding this note( both cluster should be in same domain.)

in our deployment the clusters are in different domain

What is the solution then ?

[Anurag Srivastava1]

Hello Ahmed,

In that case whether your users are using same domain for login through MRA? or different domains?
Both ways it is possible.
- If different domains then you should make collab-edge SRV for that (second) domain as well and need to resolve it to your exp-E FQDN or IP.
- Also you need to add that domain in exp-E cert SAN list.
- for different domains you need to add _cisco-uds and _cuplogin in internal DNS for their respective servers/clusters
- You need to add both domains in exp-C
- Also you need to add both CUCM and IM&P clusters in exp-C

I am not sure how many users a single pair can support for MRA, but it should work

Thanks.
Please rate if it is helpful..

[Elter]

Hello, did you implemented this topology? with two or more CUCM clusters, each one with its own domain, sharing the same Expressway pair?

Do you know if it is a supported scenario?

Thanks