SIP trunk to connect two CUCM clusters

[Eugene Meyer]

Hi.

We have two CUCM clusters (Cluster A and B), which we would like to connect with a SIP trunk.

The cluster topologies are as follow.

Cluster A (UCS 8.5)

Consist of two leaf clusters (a and b) Each cluster contains 1 Publisher, 2 TFTP server, and 3 Subs, and 3 Backup Subs.

Leaf clusters connect to SME cluster (2 servers) via SIP trunks

SME cluster connects to GW (MGCP)

GW connects to Siemens PBX

Siemens PBX connects to PSTN.

Number range for Cluster A: 010 340XXXX and 010 212XXXX

Use 7 digits short dial within site

Cluster B (MCS 7.1.3)

Consist of 1 Pub and 2 Subs

Cluster connects directly to PSTN via Gateway ((MGCP)

Number range for cluster 010 885 6000 - 8000; 560 7000 - 7800; 582 0001 - 2600.

Cluster connects to a H.323 GK which connects the cluster to London.

Use 5 digit short dial within site

We would like to connect cluster A and B together with SIP trunks at some point.

The motivation for this is to be able to manage both clusters from one central point. At the moment we have a firewall between the two clusters (and there are a ton of other security reasons why we have not opened the firewall yet). Also, calls from cluster A to London goes across the PSTN, but from cluster B the calls route across the WAN. To cut costs we would like to route all calls to London from cluster A to cluster B, and keep the call on the WAN.

Due to security reasons we cant just connect Cluster A to the GK of cluster B.

My question here is, how to approach this. Where do we start, how will the dial plan for each cluster be affected. Is there any "white papers" to read on connecting clusters with SIP trunks, and what to watch out for.

Im trying to get ontop of this project before it kicks off, so tips on where to begin, what to look out for, and how to approach this would be much appriciated.

[Ayodeji Okanlawon]

I am not sure I understand your query.

Your setup looks like this..

                            Cluster A    -----------SME CLUSTER

                              Clusetr B-------------SME Cluster

Is this correct?

If it is then life is easy...Calls between clusters can be routed via the SME cluster.  I have used this before and it works great! Youc an even use SAF to automate dial plan advertisement...

Is there a seperate London cluster?

Please clarify your thoughts

[Eugene Meyer]

Hi aokanlawon.

No, Cluster A has a SME cluster, which connects to 2 leaf clusters. Lets say this cluster belongs to Company A

Cluster B, has 3 Servers in its cluster. 1 Pub and 2 Subs. This cluster belongs to Company B. Company B is global and has a GK which connects Cluster B to London.

Cluster A: PSTN --> Siemens PBX --> GW (MGCP) --> SME Cluster -->SIP Trunks --> Leaf clusters A & B

Cluster B: LDN --> GK (H.323) --> GW (MGCP) --> CUCM Cluster.

We would like to connect the clusters of company A and B together with SIP trunks.

I hope this clarifies the question

[Eugene Meyer]

Oh, and yes. There is a seperate cluster in London, but we dont want to connect directly to it. The aim here is to connect the local cluster of company A and B together here. If that makes sence.

[Ayodeji Okanlawon]

Yes thanks for that. Next question is is there restriction using the SME cluster in Cluster A, to connect cluster B? Making it another leaf cluster on it. This will be the easiest approach. such that you will have something like this

Cluster A1, A2------->SME----->Cluster B

[Eugene Meyer]

No restriction what so ever. This is what I had in mind, but not sure where to start.

[Ayodeji Okanlawon · Accepted solution]

Beautiful! Relax your life is easy. Thats what SME does for you!

Here is the csico WIKI on SME..quite useful..

http://docwiki.cisco.com/wiki/Unified_Communications_Manager_Session_Management_Edition_System_Test_Configuration_Release_8.5(1)

Here are my pointers

1. All you need is a sip trunk between SME and Cluster B. You already have a sip trunk to cluster A1, A2

2. How does SME route Cluster A calls to Cluster B? Via the sip trunk and route patterns

3. You need RP configured on Cluster A1, A2 to Dial-plans for Cluster B to be sent to the SME ( the beauty of this is that you can have all calls to any cluster sent to the SME. You can achieve this with a single route pattern )

4. On SME you will then configure RP to Cluster B pattern to go out via SIP trunk for Cluster B

5. In terms of dial-plan management. The best rule is to have unique dial-palns. If you have overlapping dial-plans you can use site-codes to distinguis between sites, this will make things easy to configure route patterns on your SME cluster

You can then use xlation patterns on each cluster to strip off site codes.

6. Ensure you plan your CSS, PT carefully and assign then properly.

This is how I have done this in the past. It works great. You can even route calls out the SME to anything hanging off it. PBX, PSTN etc

Dont forget to rate useful posts

[Eugene Meyer]

Hi aokanalwon.

Thanks for the advice. Much appriciated. The docwikki is empty thou

If I run into more questions I will repost here.

Thanks for the help.

[Ayodeji Okanlawon]

The link is empty because when you click on it, the closed parenthesis on the 1 is missing...if you add it it will work.. Or if you copy the whole link and paste on your browser it will work

Eg you have 8.5(1  on the last line of the link when you click on it, it should be 8.5(1)

http://docwiki.cisco.com/wiki/Unified_Communications_Manager_Session_Management_Edition_System_Test_Configuration_Release_8.5(1)