Tag Archives: Mediation

Step by step Mediation Server Pool: Skype for Business Server 2015 PartII


In my preceding post, I have covered step by step deployment process of Mediation server pool. This post covers the step by step process to add mediation server in an existing pool.

Open PowerShell and add following features.

Add-WindowsFeature NET-Framework-Core, RSAT-ADDS, Windows-Identity-Foundation, NET-WCF-HTTP-Activation45, Web-Asp-Net45 -Source D:\sources\sxs

Run windows update (KB2982006).

Install Silverlight.

Insert Skype for Business Server 2015 media and run setup.exe.

Run “Install Administrative Tools”

Open Topology Builder and add mediation server pool.

Right click on Mediation pool and click on New Server…

Write second mediation server FQDN.

Now publish the topology.

Open Deployment Wizard and run “Install or Update Skype for Business Server System”

Run “Install Local Configuration store”

Run “Setup or Remove Skype for Business server Components”

Now go to the first mediation server and export the mediation server certificate.

Run “Request, Install or Assign Certificates”

Now import the certificate and assign it.

Follow the same process to add more mediation server in the pool.

Once you are done start services on all the mediation servers by running “Start-cswindowsservice”.

Step by step Mediation Server Pool: Skype for Business Server 2015


In my preceding post, I have covered step by step deployment process of Front End server pool. This post covers the step by step process to deploy mediation server pool. You need to make sure your FE pool is up and running and follow the process as given below.

Join all the mediation servers to domain and login to first mediation server.

Open PowerShell and add following features.

Add-WindowsFeature NET-Framework-Core, RSAT-ADDS, Windows-Identity-Foundation, NET-WCF-HTTP-Activation45, Web-Asp-Net45 -Source D:\sources\sxs

Run windows update (KB2982006).

Install Silverlight.

Insert Skype for Business Server 2015 media and run setup.exe.

Run “Install Administrative Tools”

Open Topology Builder and add mediation server pool.

Once Mediation Server Pool is added with at least one mediation server, publish the topology.

Open Deployment Wizard and run “Install or Update Skype for Business Server System”

Run “Install Local Configuration Store”

Run “Setup or remove Skype for Business Server Components”

Run “Request, Install or Assign Certificates”

Request Certificate.

Fill the required fields and click on Advanced.

Write friendly name and select “Mark the certificate’s private key as exportable”

Add other mediation servers which are going to be part of your mediation pool.

Click on Next.

Now assign the certificate.

Once certificate is assigned, close the window.

Part II of this post covers installation of adding mediation server to an existing mediation pool.

Collocated or Stand-alone Mediation Server


Most of the time, Lync Enterprise voice deployments need debate for collocated or stand-alone mediation server. Collocation of Mediation Server can reduce the TCO and data center footprints. Can Mediation server collocation be a wise option? To choose a wise option out of collocated or stand-alone mediation server depends on the following:

  1. Number of users enabled for UC-PSTN calls
  2. Number of UC-PSTN calls per user per hour
  3. Number of UC-PSTN calls at the time of peak load
  4. Connected gateway / SBC and mediation server
  5. Percentage of calls that support media bypass
  6. Branch sites configuration for UC-PSTN deployment

If I have missed any point here, please leave your comment so that I can add the same.

Any call which initiate from any Lync endpoint has two components signaling and media. For UC-PSTN calls, signaling always goes through Mediation server if stand-alone or Standard Edition / Front End server collocated with mediation server role.

No Media Bypass:

Media Bypass:


If your gateways, SBC or IP-PBX support media bypass, you can use collocated mediation server. But if you are planning for an option which do not support media bypass, I will advise you not to use collocated mediation server as collocated meditation server will increase load on front end servers which can cause of poor performance.

If you still want to use collocated meditation server, you can increase number of front end servers which can help you to distribute the load among front end servers.

A Stand-alone Mediation server deployment also depends on Branch sites which are connected to central site. If your branch sites don’t have dedicated PSTN connectivity then you should go with stand-alone mediation server pool. Again this topic requires more debate. As we know Lync 2013 use M:N trunk, in simple way it means if you have mediation server deployed in branch site and that can support media bypass you can still go with collocated option.

You can use Lync Planning tool to try all options and choose best out of that which provide you better ROI and best performance.