By default, the Mediation Server role is collocated with the Front End Server role. Microsoft supports collocation of the Mediation Server role with the Front End Server role, but no other server roles. Although it is supported, collocation should be carefully planned for based on the following:
• The number of gateway peers the Mediation Server will be connected to
• The amount of traffic through those gateways
• The percentage of calls that are enabled for Media Bypass
The Mediation Server can require heavy processing for media traversal and transcoding in some scenarios. Often, small organizations can collocate the Mediation Server role; however, many larger organizations will require dedicated Mediation Server ...