Media Bypass

Planning for Media Bypass is not too complicated because it only encompasses identifying which IP/PSTN gateways in the organization support the feature and then configuring the trunks appropriately to enable the support. The majority of the configuration typically involves defining the network topology correctly. Media bypass enables a Lync endpoint to communicate directly with an IP/PSTN gateway, bypassing the Mediation server role. Figure 28.7 displays how a user’s signaling traffic continues to flow through the server to the IP/PSTN gateway, but the actual audio stream is sent from the user directly to the IP/PSTN gateway.

Figure 28.7 Media Bypass

Media Bypass is especially useful in branch office scenarios where no Mediation server is present, but a local IP/PSTN gateway exists. Without Media Bypass, calls are sent across a WAN link to a Mediation server at the central site, transcoded to G.711, and then sent back across the WAN link to the IP/PSTN gateway. With media bypass, endpoints can send the G.711 audio directly to the IP/PSTN gateway without traversing the WAN.