A potentially confusing point for organizations trying to deploy Lync Server 2013 is how the Edge Server fits into a network from a logical and physical perspective. Various methods can be used, as discussed in this section.
The key point to keep in mind is that the Edge Server requires two network adapters. One is internal-facing and communicates with the internal Front End Servers, Directors, and clients, and the second adapter is external-facing and communicates with the external traffic from the Internet. The two network adapters must also be in distinct networks, or VLANs (virtual LANs), to be officially supported by Microsoft.