Chapter 4. Introducing the Lync Mediation Server

After the previous chapter, dedicated to Lync mobility and external users access, we will introduce the Lync Mediation server that is part of every voice deployment, along with the dial plans, voice policies, and the voice routes that will be explained in Chapter 5, Getting Started with Lync Enterprise Voice.

Starting with Lync 2010, Microsoft has added some essential features regarding the enterprise voice, such as resiliency (users can continue making and receiving calls if the server, where they are homed becomes unavailable), call number manipulation (required to present the telephone numbers from Lync in a format that is compatible with the different hardware and telephonic providers), and media bypass (that is explained later in this chapter).

A big part of the "magic" is due to the Mediation server role of Lync. Mediation servers are responsible to manage the communication between the Front End Servers and the gateways, such as a SIP...