Planning for Network Infrastructure Requirements

When planning a basic Lync Server 2013 deployment, don’t forget to take into account the needs you will have of the network. Take into consideration plans for how servers will be logically deployed when planning for their physical deployment. For example, if multiple Front End Servers are load balanced for redundancy, consider placing them into different physical racks and connecting them to independent power circuits.

When planning the requirements for the LAN (local area network) or WAN (wide area network), there might be some deviation between predicted loads and actual observed loads. Take this under consideration when evaluating whether existing network connections will handle the added load of Lync Server 2013.

Use the following rules of thumb for Lync Server 2013 when planning network usage:

• Plan for 65Kbps per audio stream and 500Kbps per video stream as peak values.

• Bidirectional audio and video sessions count as two streams.

• Lync Server media endpoints can adapt to varying network conditions and can usually handle oversubscriptions of up to three times. Although an audio stream peaks its usage at 65Kbps, you can typically run three audio streams in the same 65Kbps without users noticing a drop in quality.

• If a site lacks the capacity to comfortably run video streams, consider disabling video for that site.

• Expect degraded audio and video performance between endpoints separated by more than 150ms of latency.

While Lync supports QoS through DSCP tagging, it is designed to work well in environments without QoS, such as the Internet. By default, Lync assigns a DSCP value of 40 for voice and video traffic.