Migration and Interoperability Options – Cisco Unified Communications and Microsoft Lync Server 2010

Unless you had the pleasure of being an approved TAP customer for Microsoft Lync Server 2010 this year it is likely that many customers have at best implemented an RC lab or more likely watched with interest the online content being produced by Microsoft, myself and other unified communication professionals.  With every new product upgrade customers are always face similar challenges, particularly in the areas of investment, interoperability and deployment strategy.

Organisations make a significant investment when choosing an enterprise voice solution, the idea of implementing more than just a PBX solution has been with us for some time now making the costs even more substantional.  With some manufacturer handsets alone costing £250+ each (before backend services, licensing, applications and on-going maintenance is considered) it is no surprise that the enterprise voice services is something organisations do not expect will require investment very often.  The future dominant force in unified communications will certainly not achieve market share overnight simply because of the investment some customers have made in recent years, as with every technology there is always something better just round the corner.

Although guidance preparing ROI information and a business case is an essential part of the consultant role it can be an area where the concept of total enterprise voice product displacement is solely promoted, sometimes at the cost of an actual sale.  Even in the scenario where Microsoft unified communications will be adopted throughout the enterprise interoperability with the existing telephony solution is essential before a successful migration can be concluded.  I’m confident that the marketplace has been waiting eagerly for the launch of Lync Server 2010 and there will be a flood of opportunities.  Information on what Microsoft unified communications can deliver has been seeded for some time now and more people with an interest have been attending recent user group and product launch events. 

Of course the major players in the market are constantly stating support and interoperability.  Open standards are an area every market player is certainly encouraging because it can only help deliver unified communications increased traction in the market place.  Earlier this year for example the Unified Communication Interoperability Forum (UCIF) was created.  The UCIF is a non-profit ecosystem of communications technology vendors with a shared goal to bring the promise of truly unified communications to life.  You can find out more about UCIF here.

Ultimately commercial return plays a key part in what customers hear from “the experts” which can cloud the decision-making process unnecessarily in one of the biggest areas of investment for any organisation.  So in this and future posts I will focus on some of the more common scenarios faced by organisations and highlight the advantages or disadvantages of each deployment strategy.  The post today will focus on Microsoft deployment options when Cisco is the incumbent voice technology; it is certainly a common question I’m asked about…

The reason why this is a popular topic is simply because Cisco has seen widespread adoption before Microsoft entered this market sector.  Microsoft themselves for a period of time were somewhat reducing the deployment options available for organisations when communicating initially Remote Call Control (RCC) was being dropped for new customer deployments, a decision thankfully reverted.  Details of what “Click to Call” (formely called RCC) allows is provided later in this post.  I hope you find the rest of this post summarises the options and considerations sufficiently.

Option1 – Cisco product displacement

If you intend a total replacement of the existing Cisco unified communications architecture it is important considering that commissioning Microsoft Lync Server 2010 and Exchange 2010 products is not the only area of investment.


Firstly you must consider carefully the level of interoperability between Cisco and Microsoft products which have been officially qualified so initial co-existence can be established.  It is worth reviewing the Microsoft Unified Communications Open Interoperability Program so it is can be confirmed if the existing Cisco products in operation require remediation works.  Repeating the words of Microsoft

“This qualification program for SIP/PSTN Gateways, IP-PBXs and SIP Trunking Services ensures that customers have seamless experiences with setup, support, and use of qualified telephony infrastructure and services with Microsoft’s unified communications software and Microsoft Office Communications Online (BPOS-Dedicated)”

Only products that meet rigorous and extensive testing requirements and conform to the specifications and test plans will receive qualification so it is essential that any remediation works on the existing Cisco infrastructure is identified, planned and priced.

Client Experience “Comparing Apples to Apples”

Demonstrating the capabilities of the Lync client in a Microsoft enterprise voice configuration is certainly positively received by all who see the product in action.  There is plenty of material available on the web regarding the features and training available.  However it is important that you understand other deployment methods mentioned later in this posting will provide a different user experience, and indeed more importantly perhaps less functionality.  Comparing Apples to Apples is important if you are reviewing a Microsoft only solution or co-existence strategy.

The client deployment of Lync and back-end configuration is certainly worth designing in conjunction with an experienced unified communications professional.  Remember that product demonstrations are indeed a great crowd pleaser but only a “proof of concept” within an organisation will highlight the level of functionality on offer and the potential remediation works needed.  If I’m presenting at an event the demonstration will be using the latest product iterations e.g. Microsoft Windows 7, Office 2010 and the best hardware on offer at the time.  Ultimately the client configuration will impact the experience and functionality on offer.  For example one key benefit I find with the Microsoft Lync solution is application integration where I can communicate by whatever method I find most appropriate from within the application I’m using.  The user experience does differ depending on the version of Microsoft office installed, but please remember Microsoft enterprise voice is the only deployment method where you will not be installing additional products (see later in post) for the fully feature rich experience.

Benefit of gateways

The Microsoft vision stated some years ago could simply not be achieved without a comprehensive ecosystem of strategic partners.  One area which provides a dramatic impact on overall deployment success is the gateway vendor offerings.   For example, customers can choose among gateways from multiple vendors that provide connectivity and interoperability between PSTN access and the existing PBX systems.  Solutions are available from NET, Audiocodes, Dialogic, HP and Ferrari.

Survivable Branch

If Cisco unified communications is the incumbent PBX technology there is every chance that a Cisco Integrated Services Router (ISR) will be deployed in branch locations, primarily for terminating local PSTN services and configured with Cisco Unified Survivable Remote Site Telephony (SRST).  This is a feature set embedded in the software running on the Cisco routers and will provide multi feature call-processing redundancy for centralised Cisco Unified Communications Manager deployments if the branch WAN connection is lost.

With an enterprise voice deployment of Lync Server 2010 the same capabilities as Cisco can be provided via the various survivable branch appliances on offer.  It is important you identify the correct gateway manufacturer and model selection for each individual requirement.  Simply put the user count and PSTN service will specify the model needed but keep in mind each gateway vendor provides additional features. 

Added functionality

An example of the added functionality is NET’s pioneering directory-based Call Routing which enables the VX NET gateway product range to make call routing decisions based on user information stored in Microsoft Active Directory(AD).  AD integration helps in easily migrating users to Lync from the legacy PBX. This provides IT administrators with a single point-of-control for user moves, ads, and changes. AD integration also supports a variety of other call-routing scenarios.  For organisations in transition to Microsoft unified communications, for example, it allows the NET VX switch to determine whether a call should be routed directly to a user’s PBX phone, mobile phone or via the Lync client.  In fact, AD integration opens up a universe of possibilities for rules-based call routing – including the programming of failover scenarios that direct calls to users’ cell phones in the event that LAN/WAN connections to UC desktops are down.   

Legacy support

How many offices have you visited and there was not a fax machine, security alarm or elevator lift phone in sight?  If you visit industrial facilities then the list of legacy analogue needs gets longer, examples including external ringers and intrinsically safe handsets.  Again gateway manufacturers can deliver products which can service these legacy device needs.  Indeed gateway manufacturers have now been providing a mechanism for reutilising some existing Cisco handsets which is an interesting development.

With the investment many organisations have already made in handsets growing demand for a solution to extend the useful life of existing SIP Phones has led to some innovative solutions.  An example of this support is SmartSIP, an application built using Microsoft Unified Communications and manufacturerd by NET.  This solution allows for different implementations of SIP protocols to coexist.  Therefore, the following Cisco handsets, 7940/7960/7911/7906, can be retained and interoperate with Microsoft unified communications.  More details of this product can be found here.

PSTN migration strategy

Finally the gateway manufacturers can really make a migration strategy painless by effectively terminating communications between the internal enterprise voice solution and PSTN services.  ISDN is still the norm PSTN service in place with organisations but SIP is gaining significant traction.  If someone is already making use of Cisco unified communications the ISDN services will have been converted from more legacy signalling like DASS onto a Q.931 standard.  However more and more organisations are also transitioning onto the SIP services and in this area gateway manufacturers can provide products which can indeed accommodate both, making the transition painless both for the internal enterprise voice solution and a change in PSTN service provision.

Other considerations

So what other considerations should you think about?  Well of course the underlying networking and LAN infrastructure must be carefully assessed before introducing unified communications onto the production network.  I would recommend you pay particular focus on profiling the end user requirements.  When people communicate today outside the workplace they have a wide selection of options available and use them with ease but we all know unfortunately it is not the norm within many organisations today.  People have proliferating options available and you should profile what is best for that particular user of the system when adopting Microsoft unified communications, user buy in is essential.  The user experience is certainly intuitive but is training necessary? What end device is most appropriate for their needs? What is the typical location of usage e.g. mobile/remote are only a few examples for consideration. 

If you invest in Microsoft unified communications please do not short change the user by purchasing end devices which are not optimised for Microsoft unified communications.  Yes, you can get a cheap end device working but the experience will be dramatically impacted by the device in operation.  Choosing from the range of devices  “Optimized for” Microsoft unified communications and empowering the end user in product selection will deliver a positive experience for all concerned.  Again, just like the gateways there is multiple manufacturers making quality end device products including Plantronics, Polycom, Aastra, GN and SNOM.  I’ve previously posted on why choice in this area is a fantastic development, no longer will someone I’ve never met in the IT department dictate a two line handset is best for my needs (and more likely that decision was made because I wasn’t ranked high enough for a four line handset!!!).

Finally it is worth noting that internal staff with specific skills (or a desire in obtaining them) will have a particular interest in the unified communications strategy.  This is an area which can influence the final design and must  be addressed by education, envisioning and collaboration with the key staff.  If anyone has statistics on %headcount by role within an IT department I would find it very interesting.  The point I would leave you pondering on is who can best maintain a full feature rich enterprise solution that delivers more than voice?  Often there is many more server application staff than telephony resources in the internal IT organisation.  Although enterprise voice skills are needed for deployment success it is an interesting time in the market as telephony, server, network, application and development staff are ever increasingly breaking down the silos of traditional responsibilities.

Option2 – Cisco and Microsoft co-existence

Although this is titled Option 2 there are actually two Cisco co-existence offerings available and described below.  If you wish the benefits of Microsoft unified communications but displacing existing Cisco infrastructure investment is not a consideration, Click to Call (formely RCC) and CUCIMOC may satisfy the needs of an organisation.  I mentioned previously that Microsoft provided a variety of deployment methods and one popular choice is Remote Call Control (RCC) which has been available in previous product iterations.  Effectively with RCC the telephony PBX services is satisfied by the existing telephony infrastructure and Microsoft functionality is wrapped around it.

Some words of caution are appropriate at this point in my post.  The challenge with a co-existence strategy is obvious, firstly you will pay much more for retaining both systems in service, there is now more products requiring on-going maintenance/interoperability and end functionality will be less.  Functionality is certainly an important consideration because the end user experience will simply not be the same.  Users will miss out on call escalation, party to multiparty conferences, have limited presence support with no Do Not Disturb integration and no Presence level access to Team.  If an end device is hard coded into the configuration and you are dealing with mobility the complexity increases.

So when Microsoft stated RCC would only be supported for existing Microsoft Office Communications Server RCC deployments upgrading onto Lync it caused a stir in the industry.  If you think about it for a moment RCC may be enough depending on an organisations initial unified communication needs.  However the momentum for then completing a migration onto a full Microsoft unified communications solution diminishes.  However Microsoft has stated that Lync Server 2010 will support Click to Call (formely called RCC) for new customers so this option is available for the foreseeable future.

So how does Microsoft Click to Call work with Cisco?  Well within an existing Cisco Unified Communications Manager infrastructure an additional Cisco product is necessary, named Cisco Unified Presence.  Why I hear you ask?  Well a summary is provided below but I would encourage reading the TechNet article “How Remote Call Control Powers OCS 2007 R2” in the first instance before understanding what each specific Cisco product component delivers.  RCC is the ability to send or receive calls on a device other than your computer so for Microsoft Lync, this means the following:

  • When the PBX phone rings, an alert appears in Lync that allows you to answer the call.
  • When someone’s phone number is clicked on Lync, the PBX phone goes off-hook in speakerphone mode and dials the number.
  • Call forwarding can be set on the PBX phone.
  • Incoming calls to the number can be deflected to other phone numbers.
  • Mid-call control events, such as Single Step Transfer and Consultative Transfer, can be performed on a call on the PBX phone. DTMF signals can be sent from the PBX phone using UI in Communicator.

One of the big differences between Click to Call and Enterprise Voice configuration is that in an this configuration, Lync clients just have signalling controls set up with the PBX and there is no VoIP call sent to the Lync clients.  In other words, Lync is not being used as a softphone in these configurations.  Click to Call is deployed by setting up a SIP/CSTA Gateway between the PBX and Lync Server 2010.  The SIP/CSTA Gateway provides a Session Initiation Protocol (SIP) interface toward the Lync side and uses Computer-Supported Telecommunications Application (CSTA) signalling messages wrapped inside of SIP messages to communicate with Lync clients.  For now, to integrate communications between Lync Server 2010 and Cisco Unified Communications Manager you need Cisco Unified Presence for phone presence and phone control.  More details can be found by reading the following article, “Integration Note for Configuring Cisco Unified Presence Release 8.0 with Microsoft OCS for Microsoft Office Communicator Call Control”.

Some organisations may not have invested in Cisco Unified Communications Manager and deployed Cisco Unified Communications Manager Express (CME) on a Cisco Integrated Services Router (ISR).  In this scenario the single appliance is providing the PBX services and terminating the PSTN.  Cisco Unified Presence does not support Cisco Unified Communications Manager Express so the RCC deployment model would not have been possible had it not been for the introduction of Cisco CTI CSTA Protocol Suite with Cisco Unified CME 8.0 and later versions.  This provides third-party call-control capabilities for computer-based CSTA client applications, such as Microsoft.  In this deployment scenario, Lync uses CSTA to control its associated PBX phone via a SIP CSTA gateway residing on CME.  The Lync client interacts directly with Cisco Unified CME via the CTI interface in Cisco Unified CME to control and monitor IP phones registered in Cisco Unified CME.  More details can be found by reading the following article, “Configuring the CTI CSTA Protocol Suite”.


RCC is a solution which has been available since the earliest days of Microsoft unified communications.  Cisco then presented the communications industry with another product option in 2009, Cisco UC Integration for Microsoft Office Communicator (CUCIMOC).  This new product was introduced as an additional Cisco offering in the portfolio that interoperates with Microsoft.  Of course this isn’t the first Cisco solution that integrates with Microsoft applications.  As described earlier the only option before CUCIMOC was launched of integrating Cisco unified communications with Microsoft and retaining the Cisco handset investement was via an RCC deployment.  When you start looking at the cost of maintaining two systems, the additional Cisco Unified Presence licensing and hardware (before high availability is even a consideration) it is no surprise that Cisco recognised another solution was needed which prevented Microsoft unified communications becoming the only voice solution in operation.  A product video is available from Cisco here for the CUCIMOC application but effectively it is a client deployed application which integrates into the Microsoft client by adding an additional pane at the bottom of the Microsoft Office Communicator (MOC) client.

MOC client you say, what about Lync?  Well it will come as no surprise that an upgrade from the current CUCIMOC general release is scheduled for launch later this year.  A beta program has been ongoing for some time now and product launch is expected shortly after the product launch of Lync Server 2010.  This new product version will not only be addressing compatibility with the new Lync product line but will also deliver additional functionality as well.  Ultimately with this deployment scenario CUCIMOC is effectively tapping into the publicly available APIs Microsoft provides for all developers.  Cisco is not the only vendor providing a solution in this manner but please remember the below statement,

Microsoft does not support CUCIMOC, this is a Cisco product. Microsoft is not performing call control services with CUCIMOC

Recently someone asked me for help because they had deployed CUCIMOC and discovered issues with headset controls.  Unfortunately this is not supported as a feature at this time.  Also there is no single sign-on capability, if Microsoft AD password policy dictates a change in password this will not be replicated within the Cisco products.  Both are in the future roadmap of Cisco CUCIMOC but can I once again highlight the “Apples to Apples comparison is needed.


So in conclusion more information can easily be provided on request for any of the above deployment options.  If you haven’t read my previous posts or I have posted details on something you hadn’t heard about before from other professionals please get in touch and I can provide you more content.  My hope is the above summarises the options you have if presently operating a Cisco unified communications solution and introducing Microsoft unified communications into the estate (as a replacement or co-existence strategy).

I’m sure it is clear for all concerned that interoperability is certainly essential but ultimately any model based on co-existence introduces additional cost and unfortunately a reduction in functionality.  Organisations can quickly recognise the benefits of a truly feature rich unified communications solution, simply providing PBX services is simply not enough.  With Microsoft unified communications this functionality can be delivered via a single client if the end user is configured for enterprise voice.  Remote Call Control (RCC) can deliver a “wrap-around” option for an existing Cisco IP telephony solution.  However this may require purchasing additional Cisco product investment e.g. Cisco Unified Presence.  RCC is also an enterprise license feature, therefore you are purchasing all of the enterprise voice features of the Microsoft technology and simply not getting the same functionality via RCC. 

Personally what I find beneficial is the productivity improvements Microsoft unified communications delivers in my daily work.  Microsoft Lync isn’t far away now, you can register for the virtual product launch here or see it first-hand by attending a local partner launch event.  Of course the Cisco product line is always being refreshed as well, with the release of 8.5 relatively soon it certainly makes the unified communications market very exciting.

I hope you have found this posting useful.  If you would like more content or have any queries please get in touch so I can help you determine the best course of action.

6 responses to “Migration and Interoperability Options – Cisco Unified Communications and Microsoft Lync Server 2010

  1. Great article, very comprehensive.

    WRT to CUCIMOC, Plantronics have announced support for headset integration for CUCIMOC, and indeed all other CSF based clients, just this past month with their PURE product (Plantronics Unified Runtime Engine)

    • Thanks Dave for this information. Have you been utilising Microsoft unified communications and if so by what method? Best Regards, Andy.

  2. Great article! Finding it late, but still very informative and useful! Will recommend my customers trying to decide on a strategy to check this out!

    • Great. Many thanks for the feedback and please get in touch if I can be of any further help. Best Regards, Andy.

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