Configuring Quality of Service

Quality of Service (QoS) can be used in networks where the media traffic used by Lync Server 2010 servers and clients should have a higher priority than other traffic using the same infrastructure. This is done by having the Lync servers and endpoints tag their media traffic packets with a specific Differentiated Services Code Point (DSCP) value. Routers within the network are then configured to prioritize traffic based on the DSCP values included with packets.

DSCP marking in Lync Server 2010 is done by using the policy-based QoS first introduced with Windows Server 2008 and Windows Vista. These policies are controlled through Windows Group Policy and can mark traffic with DSCP codes based on application names and port ranges. Because these policies can be centrally managed and controlled by the organization, it should be acceptable to trust the markings sent from client endpoints. Using a separate port range for each type of traffic enables the policy-based QoS to tag the traffic appropriately. For example, audio traffic using one port range can be assigned a DSCP code with higher priority than the port range used for video or application sharing.