Home > Lync > Integrating Microsoft Lync and Cisco Unified Communication Manager Part 1: Understanding the Capabilities and Terminology

Integrating Microsoft Lync and Cisco Unified Communication Manager Part 1: Understanding the Capabilities and Terminology

This is part one of a multipart series I will be writing on the integration of two of the most popular Unified Communications systems. This is based off many hours of research and historical and recent personal experience actually doing this integration.

As in any project, it is important to understand your customer’s requirements and to set proper expectations. Microsoft and Cisco have in the past worked to provide recommendations for integrating their products but as of recently have increased the competition part of their relationship due to the realization that Microsoft has a player with Lync.

Let’s start to define the features that might be desired with a Microsoft Lync and Cisco UCM integration:

Feature Capabilities
Enterprise Voice Cisco and Lync are both fully functional Enterprise Voice Solutions and provide integrations together utilizing a direct SIP (SIP Trunk in Cisco world)
Media Bypass Microsoft Lync Server 2010 can utilize media bypass and send direct G.711 traffic to a Cisco gateway configured as a Media Termination Point (MTP)
Survivable Branch Microsoft and Cisco both provide a means for a survivable branch, Cisco through Survivable Remote Site Telephony (SRST) and Lync through Survivable Branch Appliance or Survivable Branch Server
Dual Forking / Simultaneous Ring Microsoft and Cisco both provide technology to ring another device.
Unified Messaging Both Microsoft Lync and Cisco UCM can be easily integrated into Microsoft Exchange Server 2010 for Unified Messaging. And yes, you can light the Message Waiting Indicator natively.
Call Admission Control Lync 2010 provides Call Admission Control based on Regions, Sites and Links with the ability to provide CAC to roaming users not just the device. Cisco also has the ability to provide CAC to Cisco based devices. The same CAC solution cannot control the competing product.
Quality of Service Microsoft and Cisco both utilize Differential Services (DiffServ) markings for Quality of Service.
Conferencing Conferencing can be easily provided to users of Cisco UCM and Lync utilizing Lync Server’s conferencing MCU. The conferencing MCU also has certified integrations with Polycom RMX and LifeSize MCUs through the Unified Communications Open Interoperability Program for Lync.
Remote Call Control Microsoft Lync has the ability to control Cisco desk phones in order to enable you to dial a number in your Lync client and have it make your Cisco desk phone go off hook and dial the number in Lync. This also enables presence information to pass between the Cisco desk phone and your Lync client to show that you are “In a Call” when you pick up your Cisco desk phone.

It should be noted, that I will provide some opinions and recommendations during this multi-part series of blogs, that is why this is my blog and hopefully why you read it. I write this blog because I know there are a lot of people out there looking for information on what works and not just from someone that has read about it themselves, but someone that has done this themselves and knows the good, bad and ugly. I know that there are reasons for organizations to keep their investment in Cisco, whether they are technical or probably more likely political. With all that said, let’s get started on what part 1 will focus on: Understanding the Capabilities and Terminology.

In our environment we will try to replicate what I would expect to see in any midsize to large organization. Our main location in the US has a Cisco environment built with Cisco 2851 ISRs and a single publisher and multiple subscriber nodes. Our ISDN/PRI lines terminate at our Cisco 2851 which are MGCP controlled by our Cisco UCM infrastructure. Our dial plan is centrally maintained by call manager and our 2851 is configured for SRST and has necessary configuration information to allow calls to the PSTN in the event of an outage of our cluster (which never happensJ).

We have also deployed a highly available Microsoft Lync 2010 consisting of a two node Lync Enterprise Edition Pool with DNS load balancing for the SIP traffic and a pair of Hardware Load Balancers for the HTTPS traffic. Management has decided to begin to provide users the option to switch from their desk phone to a soft phone to reduce licensing cost and provide a better user experience for users that have laptops that tend to work remotely a lot.

The decision to begin offering Lync as an alternative to a desk phone needs to come from management. There needs to be buy-in at the top levels which is not necessarily due to the capabilities but due to pushback organizations receive from telecom departments. In addition, to provide an easy to manage environment moving from a desk phone to a soft phone will typically require a user to change their phone number. This is not necessary for technical reasons, but sure makes management of both systems much easier. This is due to the fact that one system will “own” the phone number. In our implementation Cisco “owns” the phone numbers since the gateway is MGCP controlled and there needs to be either a Directory Number (DN) or a route pattern in the CUCM*.

* It is possible but an administrative nightmare to have a directory number for a number that should be in Lync, this can be done by forwarding all calls to a dummy route pattern across a SIP trunk to the Lync server. This is not recommended due to the added complexity of managing the CUCM and Lync environment. In addition, it would typically require coordination with multiple groups for implementation and troubleshooting.

Back to our scenario…

Before you begin the integration, it is important to take your requirements and map them to the capabilities of the integrated Lync and Cisco environment. One of the features that we want to implement is media bypass which allows the Lync client to talk directly to the Cisco 2851 gateway using G.711. Cisco gateways support this capability by using Media Termination Points or MTPs. MTPs are resources that do a number of functions depending on the protocol used. In our scenario, MTPs are required to provide RFC 2833 compliant SIP services between the Lync and Cisco environment such as DTMF and a relay point for media between Cisco and Lync endpoints. RTP traffic encoded with G.711 flows from the Lync client to a MTP then to a Cisco IP Phone when the client has detected that the site that it is in has that capability and the administrator has allowed and configured it.

There are two types of MTPs:

  1. Software based MTP resources can be configured on the router or CUCM Subscriber nodes. Software based MTP resources use server based hardware resources (memory, processor) and degrades the performance and capabilities of the cluster or gateway
  2. Hardware based MTP resources are configured on the gateways. These resources utilize Digital Signal Processors (DSPs) rather than the built-in hardware on the router. It is recommended to use hardware based MTP resources to provide added scalability to your environment.

A typical configuration for hardware based MTP resources will look something like this:

sccp ccm group 1
bind interface FastEthernet0/0
associate ccm 1 priority 1
associate profile 102 register LyncRouter1

dspfarm profile 102 mtp
codec g711ulaw
maximum sessions hardware 100
associate application SCCP

MTP resources, once created on a gateway will be available use on our “SIP Trunk” when we create it in our CUCM environment. It is required when we create our “SIP trunk” to enable direct SIP integration between Lync and CUCM that we require a Media Termination Point and select a of Media Resource Groups List (MRGL). A MRGL provides a prioritized list of Media Resource Groups (MRGs). In our next section, we will discuss how to complete the integration between the CUCM and Lync environments in our main site. Further sections will talk about branch office scenarios and what happens when we experience a failure. I will leave you with a high level diagram of what this environment will look like at our main site.

Categories: Lync
  1. Srini
    May 18, 2011 at 10:09 am

    Has anyone done testing of CUCM SIP to Lync where the audio/video conferencing is running on Lync server with or without CUBE? Also slight variation to this where CUCI Lync is being used but the conferencing component is being used on Lync

  2. harry
    June 9, 2011 at 3:44 am

    Thanks Mark, waiting for the next step from you. ;)) Go Go go *g*

    • June 9, 2011 at 12:54 pm

      I’m working on it 🙂
      It’s been a very busy few weeks, but not a good excuse!

  3. July 13, 2011 at 10:11 am

    This series is a must have in any toolkit.

  4. October 3, 2011 at 11:55 am


    I am an IT Director for a company based in Chicago and we are looking at changing our VOIP because it frankly stinks. Its a Fonality PBX and we are using Polycom phones. We are looking at Cisco, Avaya, Mitel, and Shortel as possibles although I am leaning towards Cisco already. I should mention that we already have Microsoft Office Communicator in our environment but our existing system doesnt integrate with it so we only use it for desktop sharing and IM, etc.

    Would there be a scenario where I could get away with just using Microsoft Lync for everything or do I need some of the Cisco gateways. I am not a VOIP guy at all so I can provide more information if necessary. Anyway I appreciate the blog.

    • October 10, 2011 at 2:34 am

      You can get away with Microsoft Lync, But you still need to have a VoIP Gateway present to hand your calls over the PSTN Network.

    • tombar
      October 27, 2011 at 6:09 am

      In that case you need to remember that additional equipment from other vendors should be included as Lync is only the call control SW. Phones, GWs, SBA, Analog adaptors, load balancers, Servers are all 3rd party.

  5. JB
    October 10, 2011 at 8:46 pm

    Part 2… bring it! keep up the great posts.

  6. October 12, 2011 at 11:32 pm

    I would use 2811+ Routers with CUBE configuration as well as have PVDM’s on the router to configure the Hardware MTP.

    Cisco Router – CUBE (I use CUBE with my PAETEC SIP trunk)
    Lync 2010 Server with proper SIP Trunk configuration and Normalization rules


  7. October 20, 2011 at 1:28 am

    Great post. I have been looking for someone who has done this. Keep up the good work and thanks for sharing.

  8. tombar
    October 27, 2011 at 6:02 am


    You mentioned your CUCM-Lync integration is based on SIP trunk, in that scenario you can’t use remote call control to control your Cisco office phone and you can’t see phone presence on your Lync client. We are using Cisco CUCI-Lync and it is a great add-on, for the end users it looks like part of the Lync client and it solve the remote call control and presence issues also admin has a single call control to manage.


    • October 27, 2011 at 11:20 am

      I have to say, you are the first person possibly in the world that thinks CUCILync is a “great” add-on or even a possible solution…

      Needless to say, my integration discussion here is around providing enterprise voice solutions with Lync and not RCC integration.

  9. tombar
    October 27, 2011 at 2:06 pm

    When you already have CUCM as call control, you have two options – to add Lync as a second “PBX” and to have two systems to provision and manage or to use CUCI-Lync and to have single call control architecture (which also solve the presence, RCC, security, CAC, management, etc. issues). Each of the two options has advantages and disadvantages – after testing both we found that CUCI-Lync has more advantages than Direct SIP trunk.

    • October 27, 2011 at 9:49 pm

      Customers implement Lync for EV and begin to decom their CUCM. A long term CUCM and Lync environment is an administrative nightmare. CUCILync removes what makes Lync great and that is simplicity and high quality enterprise voice from the internet without a VPN which is something Cisco simply can’t do. Your users that have CUCILync have a completely different user experience when they are in the office then when they are remote. That is NOT Unified Communications.

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