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mohammad saeed

Connect two CUCM remote cluster with different Lines (SIP+E1)

Hi guys,


I have two remote site of CUCM (one site has E1 and one has SIP) can I connect between both sites to be able to call local phones with each other between two sites?

or I need to make both SIP?



Mohammad Saeed


Accepted Solutions

i have many customer with the same scenario what you have. i did ICT for most cases. There are some other way as well SIP trunk or CUBE also. but i prefer to use ICT and for you i recommend to do inter-cluster trunk to avoid confusion and make it simple.


Saiful Islam

View solution in original post


What I understand is, there are two different CUCM clusters with one having E1 and other having SIP service provider connections. If you have WAN connectivity between clusters it users can call call each other through WAN irrespective of the PSTN connection type. Create a SIP trunk between cluster, or use inter cluster trunk (SIP will be preferred for me). If you are looking for something else please elaborate your question

So doesnt matter about the type if lines from isp E1 or SIP. 

But how to know if i use WAN connection. 

And i can configure sip connection between two cucm remotely even if i dont buy a sip line from isp?


Nipun Singh Raghav
Cisco Employee

You can have two CUCM clusters communicate with each other via an ICT trunk. Could be H.323 or SIP (for SIP we generally don't have a ICT but referring it since you are going to use it for inter-cluster routing).
If the two sites are using the same CUCM cluster, two ways -

1. CUCM can router calls to and from between sites through itself.
2. If both the remote sites can communicate with eachother, you can route calls without involving CUCM. All you need is a WAN or a VPN connection between them. You can use either H.323 or SIP for call control.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

Every site has its own pub+sub. Will consider two different cluster?


Solution remains the same. Either have H.323 ICT or SIP trunk b/w the clusters do the work or bypass CUCM and just have the two gateways communicate with eachother.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

Thanks for ur support. So i can use sip sitting between 2 clusters and the sip peer will be the voice gw wan ip address? And how to check if two voice gw have wan connection? Through ping?


If your every site has its own pub+sub, it is consider as two different cluster. for this scenario if you have IP network connection between two site by intranet or VPN, ideally you should configure inter-cluster trunk between this two CUCM cluster. no more confusion. for this case you dont need to think about your E1 link or SIP trunk from service provider. Link E1 or SIP from telco Service provider is used for external calls mainly, not for inter site call.

I have vpn from internet Router gateway not from voice gateway?

The costumer has MPLS between two sites!

The costumer has MPLS between two sites. Means both CUCM cluster can reach each other without VPN. if they are reachable by their MPLS connection, just do ICT without any confusion.


Saiful Islam

CCIE Collaboration

Yeah so you should have connecting b/w your sites via your MPLS, you can achieve call routing b/w the sites without VPN and without the need to go through your CUCM. You have both the options available to you like I highlighted in my initial response.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

you have vpn from internet Router gateway, not from voice gateway. This is ok. you should do Inter-cluster trunk only between two CUCM cluster. Nothing is dependent with your voice gateway for doing inter-cluster trunk. dont be confused with voice gateway or E1 or SIP trunk on Voice gateway. even if voice gateway is shutdown also no problem with your inter-cluster trunk. calls between this two CUCM cluster will work through your VPN by internet router.


Saiful Islam

CCIE Collaboration - 51594

Thanks for all now the Idea is clear, Is there any clear document or video show how to to make ICT with MPLS case..would be appreciated 

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