Integrating Mitel System into Existing Cisco Voip Infrastructure

[Sam94]

Dear friends,

I am in a fix as I am very very new to VoIP. There is a need to integrate mitel ip phones, using a Mitel 3300 controller into the network.  The phones are going to pass voice and data traffic as in standard deployment. A Vlan and a subnet will be created for this purpose.

We do have an existing Cisco VoIP infrastructure which was built before I joined, where the phones are deployed in only one building in the premises, registering through a CUCM server.  The Cisco phones are on a separate Vlan and subnet.

Bottom line is, the new Mitel phones will be required to talk to the existing Cisco phones and I can't seem to figure out how to get this done. Would an IP route between the mitel Vlan and Cisco Vlan achieve this, or there needs to be some special configuration on the CUCM server and mitel controller?

[b.winter]

Hi,

you first have to setup a connection between CUCM and the Mitel controller. Probably an ISDN connection or a SIP trunk, depending on what Mitel supports.

Then you have to configure the call routing.

E.g. Mitel controls phones with extension 2XXX and CUCM controls 1XXX.

On Mitel you have to configure, so that when 1XXX numbers are dialed, the call is sent to CUCM via the connection. Vice-versa for 2XXX numbers from CUCM to Mitel.

And since the audio streams (RTP packets) directly flow between the phones, you have to ensure that IP routing is set up between the phone subnets and that possible firewalls or access lists don't block that traffic.

Maybe the quick drawing helps for better understanding.

Green is the signalling path.

Blue is the media stream path.

--- Please rate this post as "Helpful" or accept as a solution, if your question has been answered ---

[Roger Kallberg]

Great post @b.winter One note, in this specific case I don't think that the media path would be directly between the endpoints. It would likely go via the Mitel Controller. I might be wrong on this, but this would be my guess based on other experience from similar integrations worked on previously.

[b.winter]

@Roger KallbergI agree, that could be the case.

[Sam94]

@b.winter thanks for the insight. Both vlans/subnets are outside the Firewall path (So that should not be an issue). 

[Scott Leport · Accepted solution]

Hi,

Do you have reachability between the Mitel VLAN and the VLAN where your Cisco IP phones reside? If you don't, then you will require a route. If you run an IGP / dynamic routing protocol then should be achieved by adding the necessary subnets to your routing process, but only you can really know whether or not that's required.

For the building of the SIP trunk, this link should have you covered. Can't say I've ever done the Mitel side, but the Cisco side is a standard SIP trunk config.

http://www.mitelforums.com/articles/3300/mitel-3300-Cisco-CUCM-SIP-Trunk-Configuration-guide.php

[Sam94]

Hi Scott, Inter-Vlan routing is enabled and both subnets can reach themselves. Great documentation you provided, seems pretty straightforward.

Thanks everyone, I will update the outcome in the coming days.