Expressway deployment for multiple CUCM & IMP clusters

[HusseinLTD]

Hello,

I have a customer who has the following:

3 branches (HQ, branch 1 & 2)

CUCM, IMP, CUC on each branch

all 3 CUCM are connected with SIP trunk

there's access code for each branch

they're all under one domain and one active directory.

the same users are imported from LDAP to each cluster.

I'm required to deploy Expressway (MRA) at HQ site and have it serve all 3 sites.

can I do that?

I have seen the following document and I have the exact setup.

https://community.cisco.com/kxiwq67737/attachments/kxiwq67737/5961-discussions-ip-telephony/378195/1/jabber_implementation_multiple_cluster.pdf

but I'm wondering how the registration is going to work when let's say (Branch2user1) is trying to register through MRA, how Expressway is going to determine which CUCM that user is on? since they're all on the same domain and also all of the organization's users are imported to each cluster (Branch 1&2 users are also imported to HQ CUCM)

I hope I was clear on the above details

is this going to work?

will I face an Issue if all 3 sites are using the same DNS server?

Thanks

[Roger Kallberg · Accepted solution]

This will work. The MRA Expressway will do a UDS home cluster query for the user that connects. That’s how it knows what CM/IMP it will login the user on. Just make sure that each end user is only set as home cluster in one CM in the ILS network.

[michelberben]

Interesting post for me, I am setting up a full Cisco UC deployment in 3 different countries. Plan is to deploy CUCM+IMP clusters in each country along with Expressway in each country for MRA.

I know from the CVD ( ref. https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Collaboration/enterprise/11x/collbcvd/edge.html#pgfId-1081382 ) mulitple Expressway clusters combined with Geo-DNS is possible.

Can I combine Expressway clusters and Geo-DNS with mulitple CUCM clusters ?

Also, it is 1 single domain, like in the original question of Hussein

[Roger Kallberg]

Yes, that’s what we do.

[Roger Kallberg]

One comment, deploying IMP as in CUPS now when the path forward is to use the new unified Webex application that uses the cloud centric IMP service does seem somewhat backwards. Have you looked into this?

[michelberben]

Thank you for reminding me.

They will be using Webex as softphone registered on CUCM but the presence can be taken care of by the cloud.

Still, I will need Expressway for MRA, correct ?

[Roger Kallberg]

Correct, you need MRA to connect with the UCM calling service when not at an office network or using VPN.