Tag Archives: Media Bypass

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.

Lync Enterprise Voice Connectivity


World is changing and moving towards rich collaboration and corporates can’t avoid these changes. As well as, we also can’t neglect our traditional way of communication. It means still we need phone to communicate with people. Microsoft did excellent job in this field as earlier only mailing solution was the key application for formal communication. But to understand better, we were using traditional phone. Microsoft Lync as an application can cater all your corporate needs. Microsoft Lync is a rich communication medium and easily can be integrated with other business applications such as Exchange & SharePoint.

Lync provides many options to enable Enterprise Voice. Usually organization uses traditional PBX or IP PBX which involves lots of cost and need distinct administration to manage the whole solution. Lync provides an Enterprise solution which can be deployed with or without your traditional PBX’s. In general there are three ways to enable enterprise voice with Lync.

1. Traditional PBX connectivity with Lync mediation server using media gateway.

2. Direct SIP, Advance IP PBX connectivity directly with Lync mediation server.

3. Direct SIP/PSTN Gateway/VOIP only deployment option directly with Lync mediation server.

4. SIP Trunk, Direct connectivity to Lync Mediation server from ITSP using SBC.