How to integrate OCS 2007 R2 CWA with Lync Server 2010 without Merging Lync Topology

I would like to share a few scenarios where you may need to deploy the R2 version of Communicator Web Access with Lync Server 2010. The core reason here is that the Lync Server 2010 contains a feature on the front end called Lync Web App. Eventually, Lync Web App will become a full featured web client, and however, today it is only used for users to join online meetings from the web. There is no ability to access Lync Web App from a URL and sign-in, or use it as an instant messaging too. This is planned to be released SP1 of the product, that timeframe is unknown right now.

To fill this gap, customers will have to deploy the OCS 2007 R2 CWA role, which can register against a Lync Server 2010 Pool. This post will show you how to configure OCS 2007 R2 CWA to work in your Lync Server 2010 environment without backardcompatiblesite (that is without merging 2007 with Lync topology).

Preparing the Environment

The most important thing of information in this blog, is that the Schema Prep for OCS 2007 R2 must be run in the environment before the Lync Server 2010 Schema Prep, or you will not be able to install the R2 version of CWA. If this is a deployment where there have not been prior installs of OCS 2007 R2, you will need to obtain this media, and run that Schema Prep before your Lync deployment starts, so it is very important to plan for this in your design/planning phase of your project.

Also, to get straight to the point for this blog, I assume you have prepared the schema in the correct order, have your Lync Server 2010 environment online, and have already installed the CWA Role on a server. I will walk through creating the virtual directory, as well as integrating it with your Lync environment.

Use this Deployment Guide to install and configure the CWA role

Creating the OCS 2007 R2 Virtual Web Server

One you have the CWA role installed, and a valid certificate installed on the server, you must configure the virtual web server that clients will access.

I will walk you through the process for creating an Internal web server, however the same process applies for the External web server. The difference being the types of authentication allowed, external allows forms, whereas internal also allows NTLM authentication.

Login to your R2 CWA server, and open the Communicator Web Access Admin Console

Once in the admin console, right click on your server and choose Create Virtual Web Server

Navigate through the setup wizard; choose only your Web Server Type, in my case I am choosing Internal. Make sure to select a valid HTTPS certificate when prompted. You must install the Certificate based on your server name (CWA Server name) and have the SAN created (, and update it on the Communicator Web Application Server

When you get to this section, Specify IP Address and Port it is important to note that this is the IP and listening port for your web server, not the communication between Lync and your CWA server, we will get to that next.

After entering a description for your virtual web server, the most important part of this wizard is the Specify a Listening Port section. This port defines what this application will listen on, and communicate with your Lync front end on. Because of the change in ports between OCS R2 and Lync, previously used values like 5070, or 5071 as you will see in older blog posts of mine do not work. You must pick a port that is not being used by an application currently. For my example I am using 4790.This can be any port, as long as your Lync front end and this server can communicate on that port.

Next, define your next hop pool, choose the appropriate Lync pool as your next hop and leave the port to default 5061.

Complete the wizard and start the virtual server.

Your settings should look similar to this

Now that you have completed this, you will need to make Lync aware of this server.

As you will find in the OCS 2007 R2 to Lync Server 2010 Migration Guide, you must merge your Legacy (OCS 2007 R2 components in to your Lync Topology). Our Main agenda is not to merge the OCS 2007 R2 component in to Lync Topology

Configuring Lync Server 2010

Now that we have our CWA server configured, we must make the Lync topology aware of this server. To do so, we will create a Trusted Application Server in our Lync Topology. This is possible through PowerShell using the New-CSTrustedApplicationComputer cmdlet, however I will be using the GUI.

First, navigate to your Lync front end and open the Topology Builder.

In this case we have retired the OCS 2007 R2 environment (Redeploying Communicator Web Access). Topology looks like below.

Right click on the Trusted Application server and choose New Trusted application pool

Select Single Computer pool on the Wizard

Select the next hop pool on the Wizard, click Finish

On the Topology builder you will see the Trusted Application Pool which has been Created

Right click where it says Lync Server 2010 and choose Publish Topology

Once you have published your topology, Open the Lync Server Management Shell and run the following command: New-CSTrustedApplication –ApplicationID –Port 4790 –TrustedApplicationPoolFqdn

This will create a trusted application to communicate with the trusted Application pool

To check execute: Get-CSTrustedApplication

You should now be able to login to CWA as a Lync Server 2010 user