Topic Last Modified: 2012-09-21

Media bypass is a Lync Server capability that enables an administrator to configure call routing to flow directly between the user endpoint and the public switched telephone network (PSTN) gateway without traversing the Mediation Server. Media bypass improves call quality by reducing latency, unnecessary translation, possibility of packet loss, and the number of potential points of failure. Where a remote site without a Mediation Server is connected to a central site by one or more WAN links with constrained bandwidth, media bypass lowers the bandwidth requirement by enabling media from a client at a remote site to flow directly to its local gateway without first having to flow across the WAN link to a Mediation Server at the central site and back.This reduction in media processing also complements the Mediation Server’s ability to control multiple gateways.

Media bypass and call admission control (CAC) are mutually exclusive. If media bypass is employed for a call, CAC is not performed for that call. The assumption is that there are no links with constrained bandwidth involved in the call.

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