Direct SIP Integration between Mitel Communications Director (MCD) and Microsoft Lync Server

Author: Habib Mankal
Editor: Curtis Johnstone

This document is provided “as-is”. Information and views expressed in this document, including URL and other Internet Web site references, may change without notice.

Some examples depicted herein are provided for illustration only and are fictitious.  No real association or connection is intended or should be inferred.

This document is not official Microsoft material and is solely for the purpose of assisting members in the community who which to set this environment up.




This article is a step-by-step guide to setup Direct SIP communication between a Mitel Communications Director (MCD) Version 6 and a Lync Server 2013 Pool.

clip_image002[6]Note: Mitel Communications Director (MCD) was previously called the Mitel 3300.

Configuring Direct SIP between a Mitel MCD IP-PBX and Microsoft Lync 2013 will enable voice calls from a Mitel IP-PBX to Microsoft Lync users directly using the SIP protocol (i.e. no additional voice hardware is required).

Although this guide demonstrates how to establish Direct SIP with Lync Server 2013, as outlined in the Qualified IP-PBXs & Gateways section of the Infrastructure qualified for Microsoft Lync ( ) Mitel has been ONLY qualified to work with Lync Server 2010 and MCD 4.2 as shown here:



The author has not seen any issues with Direct SIP integration with Mitel MCD Version 6 but given that it has not been official qualified this is not a supported integration. Both Mitel and Microsoft reserve the right to not provide support for this configuration should any issues arise.

The procedure for configuring a SIP trunk with MCD 4.2 is very similar if you want to use this as a basic reference guide for Version 4. The Mitel MCD form names and options are very similar but just are structured differently (than what is shown in the Mitel screenshots below).

clip_image002[7]Important Note: Please ensure that the steps involving the Mitel MCD are completed by a certified Mitel Technician and networking requirements including but not limited to bandwidth, G.711, G.729, jitter all adhere to the Mitel MCD Engineering guidelines.

Reference Topology

The step-by-step instructions in this article reference a high level topology similar to the one shown here:


Mitel Configuration

This section details what needs to be configured on the Mitel MCD v6 IP-PBX to achieve Direct SIP communications with Microsoft Lync 2013.

Configuration and Licensing

The first step is to ensure there are available SIP Trunk licenses in the Mitel IP-PBX.

Note: At a high level a SIP Trunk is the primary Mitel logical entity that that calls are routed through to Microsoft Lync.

Login to the MCD web administration tool as shown here:


Then select System Administration Tool as shown here:


Once you’re logged into the MCD from the left hand menu select Licenses -> License and Option Selection form and ensure that you have available SIP Trunk Licenses as this example shows:


Class of Service

A Class of Service needs to be configured to provide permissions for the SIP trunk to allow calls to Microsoft Lync.

Click System Properties -> System Feature Settings -> Class of Service Options as shown here:


Select a free Class of Service and Click Change. Give an appropriate name for this Class of Service (e.g. LyncSipTrunk). There are a lot of different options in this form however the below options are the only ones that need to be configured; ensure the values are set to Yes as shown here:

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Once you have enabled all the above options Click Save

Network Element

The next step is to tell the Mitel MCD how to communicate with the Lync server.

Note: If you have a Lync server pool with multiple mediation servers you will want to repeat the below process to create a network element for every Lync pool if you require fault tolerance – i.e. In the event that one mediation server goes down the MCD and Lync server can still communicate. This process shows two network elements being created.

Click Voice Network -> Network Elements


Click Add and enter the following information


Here are the values to provide:

· Name: LyncMed1

· Type: Other

· FQDN or IP Address: Use the mediation server IP or if your MCD has the internal domain DNS configured you can also use the FQDN of your mediation server.

· Click: SIP Peer check box

· SIP Peer Transport: TCP

· SIP Peer Port: 5068

Click Save


Trunk Attributes

This step specifies whether or not the Mitel SIP trunk should strip-off any digits for incoming calls from the Lync server. This holds true whether the called number is destined for an internal Mitel user or an external PSTN recipient.

Follow the steps below to configure the trunk attributes:

Click Trunks -> Trunks Attributes


Select a free Trunk Service Number and click Change to set the following:

· Class of Service: use the class of service number we created in Class of Service

· Dial In Trunks Incoming Digit Modification – Absorb: 0

· Trunk Label: LyncSipTrunk


When the “Absorb” setting is set to “0”, the Mitel trunk will not strip off any digits on the called number.

SIP Peer Profile

This next step configures the SIP features on the Mitel SIP Trunk licenses previously assigned.

You will need to create a Mitel SIP Peer Profile for each Lync mediation server used to communicate with the Mitel MCD – in our case this is two SIP Peers.

click Trunks -> SIP -> SIP PEER Profile, and then click Add


Configure the SIP Peer features as shown in the screenshots below and also ensure that you change the following:

· Network Element : set to the appropriate existing SIP Peer (e.g. Lync Mediation server)

· Trunk Service : set to the one created in Trunk Attributes

· Maximum Simultaneous Calls: set to the number of max SIP calls you want going across each SIP Peer. In the case of multiple SIP Peers and Lync Mediation Servers, it is a good idea to equally distribute the amount of maximum simultaneous calls between the SIP Peers in order to have balanced redundancy. For example, if you had 20 Mitel SIP Trunk licenses and two SIP Peers and Lync Mediation Servers, you would specify 10 max simultaneous calls per Mitel SIP Peer Profile.



Call Routing

The last step for the Mitel configuration is to set a several more options which tell Mitel how calls route to Lync.

Select Call Routing -> Automatic Route Selection (ARS) as shown here:


Next, follow these steps:

1. First we need to create an ARS Digit Modification, so click on the ARS Digit Modification Plan and pick a free one and ensure that the Number of Digits to absorb is 0, this is so when you’re dialing an extension on the Lync side from Mitel or externally we don’t strip away any numbers, in this case we have moved over users from Mitel to Lync. The is another type of configuration that I’ll show in another blog post to ring both your Mitel phone and Lync Enterprise voice number so you can choose which one you want to pick up.

2. Click ARS Routes, Click Change Page

· Select a free ARS Route and modify the fields appropriately as shown in the screenshot below and repeat for as many SIP Peers you have created. Configure the following settings to have these values:

1. Routing Medium: SIP Trunk

2. SIP Peer Profile: Select from the drop down list

3. Digit Modification Number: Enter the one created in the above step.

Click Save


Continue with these steps:

1. ARS Route Lists: Find a free route list and click Change, this is where you setup the redundancy for the mediation servers if one mediation server is down or the calls are maxed out on the SIP Peer it will go to the following one. Unfortunately it’s not a round robin or circular list it always starts from the top down.

1. 1st Choice route: Enter the first ARS route number created above.

2. 2nd Choice route: Enter the 2nd ARS route number created above.

3. Repeat until step 6, DO NOT enable Warning tone as the caller will hear a tone when bouncing from one choice to the next.

4. Click Save.

2. ARS Digits Dialed – this last form is where you will specific the digits needed to dial in order to communicate to the Lync Server. There are a few scenarios on how to configure this, here are two scenarios:

· Scenario 1: If you are moving a range of users then you can build a route that encapsulates the entire range for instance if we are moving the entire 2500-2599 block over to Lync we do the following, Click Add and provide the following values for the following settings:

1. Digits Dialed: 25

2. Number of Digits to follow: 2

3. Termination Type: List

4. Termination Number: The list number we created in step 1.


5. Click Save

6. Now when a user dials a number in the 2500-2599 range on a mitel phone or externally in the call be sent over the sip trunks to Lync.

· Scenario 2: If you want to move an individual person from Mitel to Lync, it’s not as clean as the above configuration but it still works. Say we are moving extension 2001 over to Lync, the best way to do this so we don’t mess with existing dialing rules is to create a new set of rules and manipulate the numbers in order to send the call across, here is what needs to be done:

1. Find a free ARS Digit Modification Plan and set the numbers to absorb to 2 you can use 3 or greater be careful to manipulate these numbers in the ARS Digits dialed.

2. Create a set of new ARS Routes like you created earlier in the document, and set the digit modification number to the one you just created in the step above.

3. Create a new ARS Route List and associate the ARS Routes you created.

4. Create a new ARS Digit dialed

a. Digits Dialed: 75 (or any other number range that is not in use)

b. Number of Digits to follow: 4

c. Termination Type: List

d. Termination Number: The new ars route list you created.

5. What we’re doing is saying if someone dials 752001 we are going to strip the first 2 digits and then route the call over the Lync SIP Trunk

6. In this last step we configure the Mitel MCD so that our users do not have to remember having to add the 75 in-front of the number when they dial it – so we create a system speed call as shown here:

· System Properties -> Systems Feature Settings -> System Speed Calls

· Click Add

· Speed Call Number: 2001

· Actual Number 752001

Now when a user dials 2001, we send the call to 752001 and then strip the first 2 digits off before sending it to Lync.

Lync Server 2013 Configuration

This section describes what needs to be configured on the Lync Server 2013 side if the SIP connection.

Adding the Mitel MCD IP-PBX into Lync Server 2013 topology builder

To start configuring Lync, log into your Lync Server 2013 Front End Server (standard or enterprise):

· Open the Lync Server topology builder

· Edit your mediation pools and ensure you have the TCP Port check box selected to allow the mediation server to start listening on the ports specified (in this case 5068).

· Click Ok


· Add a new PSTN Gateway to the topology and make sure you select TCP as the protocol and port 5060 for the port the gateway is listening on.


· Publish the topology.

Create a Dial Plan

A Lync dial plan is required to normalize the inbound and outbound dialed numbers (Lync called,calling destination number) into E.164 format.

Open the Lync Control Panel and browse to Voice Dialing -> Dial Plan -> Global as shown here:


Open the Global Dial plan and Click New as shown here:


There are a several different ways to inbound normalize numbers into a format that best suites your environment (more content about Lync number normalization can be found on Microsoft TechNet and other sources).

In this guide we are using extension numbers in Lync for our users (e.g. Tel:+16135990047;ext=2001) so we need to normalize the number to be E.164 when the call comes in by creating the following rule as shown here:


You can add more normalization rules to satisfy the requirements of your environment.

Click OK once you are done. Be sure to Commit all changes in the Lync Topology builder.

Voice Policy, PSTN Usage, and Route

This step instructs the Lync Server where to send an outbound Mitel call, and which Lync users are allowed make such calls.

The Lync voice Route you will create below will configure Lync to send the outbound Mitel call to the PSTN Gateway that provides the Mitel connectivity when a Lync user dials a Mitel number.

Open the Global Voice Policy and under Associated PSTN usages click New to create a new PSTN Usage as shown here:


Provide a meaningful name and then under Associated Routes Click New to create a new Route as shown here:


The easiest way is to enable all calls to be able to traverse out after the number has been normalized so configure your Route to match the pattern .*

Associated Trunks:

· Click Add, and select the new PSTN gateway you previously added and click OK

· Now click OK to save the new Route

· Now click OK to save the new Pstn Usage Record.

· Click OK to save the Global Voice Policy

· Commit all changes

Trunk Configuration

Lastly we need to configure the Lync trunk to:

· optionally use Encryption

· remove the normalized number and only send Mitel the 4 digit number we are trying to call.

Edit the Global Trunk Configuration and under Encryption Support Level select Optional from the drop down list and click OK and Commit all changes as shown here:


Scroll down to Called number translation Rules – > Click New


· Name: Provide a meaningful name

· Build a Translation Pattern -> Click Edit

o Pattern to Match: ^\+16135990047;ext=(\d{4})$

§ Where we want to match the full number and the 4 digit number that was entered

o Translation Rule: $1

§ Remove all the phone number except for the 4 digit number entered.

· Click OK


To validate the rule you just created

· Click -> Called number

· Phone number to test: +16135000047;ext=2001

· Click Go, the translation rule number will now show 2001 and send that to the Mitel which it will understand.



Mitel users and Lync users should now be capable of placing calls to each other over the newly created SIP Trunk.

Future articles will continue this configuration so that your Mitel phones will simultaneous ring your Lync Enterprise voice number.

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