Media Bypass

One of original roles of the mediation server was to transcode between RealTime audio (RTAudio) and G.711 to integrate with standards-based media gateways and PBXs. With Lync Server, calls can be sent using G.711 directly to a supported gateway or PBX. Although low bandwidth signaling (SIP) still traverses the mediation service role, higher bandwidth media (RTP) flows directly from a Lync Server endpoint to the GW/PBX, bypassing the Mediation Server role.

This change provides several benefits, including

• Removes a potential single point of failure that a mediation server introduced

• Reduces the overall server footprint of OCS

• Reduces the number of hops a media stream takes

In addition, in scenarios where a branch appliance is deployed, calls from PBX users at a branch to Lync Server users at the same branch, media now remains at the branch. Prior to Lync Server, an extra mediation server at the branch was required to enable similar call flow.