The Lync Server 2013 Protocol Poster is now available to the general public.

Related: What's New in Lync Server 2013

Since Microsoft Office Communications Server (OCS) 2007 R2, experts in the Lync community have been creating this poster to illustrate Lync Server's network traffic. The Lync Server 2013 Protocol Poster is divided into several sections, including sections covering:

  • IM and presence workloads
  • A/V and web conferencing workloads
  • Enterprise Voice workloads
  • Application sharing workloads
  • Central Management Store (CMS)

These five key sections dive into the protocols, ports, and routing paths for Lync Server 2013 traffic between the different server roles. Let's take a look at each key section so that you can get more familiar with the poster.

The IM and Presence Section

Together, IM and presence is often considered the most basic mode of Lync and one that's expected to work right out of the box after a deployment. (In case you're unfamiliar with Lync, presence is a feature that displays a user's availability, willingness to communicate, and contact information.) As you can see in Figure 1, the poster's IM and Presence section shows all the traffic that's handled over the Session Initiation Protocol (SIP).

Poster's IM and Presence Section

The section also shows Lync Server 2013's new sign-in process from both a remote user's and internal user's point of view. It breaks down the sign-in process step by step. In addition, this section illustrates how Lync Server 2013's new server role—Centralized Logging Server—interacts with the Edge Server, Director Server, Persistent Chat Server, and Front End Server roles.

The A/V and Web Conferencing Section

The poster's A/V and Web Conferencing section breaks down all things related to audio, video, and conferencing from a protocol point of view. As you can see in Figure 2, the new Office Web Apps Server is included in this section.

Poster's A/V and Web Conferencing Section

The poster explains how the Office Web Apps Server handles PowerPoint presentations from external and internal clients in the Lync 2013 environment. Another interesting area that gets some much needed in-depth attention is the protocols that are involved with conferences handled by remote clients through the Edge Servers.

The Enterprise Voice Section

The network traffic for Enterprise Voice (Lync's VoIP functionality) can be harder to grasp compared to thenetwork traffic for the other workloads. The poster's Enterprise Voice section shows how voice travels through the Edge Servers, a process that's better known as Simple Traversal of UDP over NAT (STUN). The STUN process leverages the Interactive Connectivity Establishment (ICE) industry standard protocol of sending media over a firewall. Of particular importance is the Secure Real-Time Transport Protocol (SRTP) traffic and the paths it takes through the Edge Servers to the Enterprise Pool, as shown in Figure 3.

Poster's Enterprise Voice Section

The Application Sharing Section

The poster's Application Sharing section covers two areas of importance—the remote usage scenario and the internal usage scenario—as shown in Figure 4.

Poster's Application Sharing Section

In the remote usage scenario, one or both of the users who are sharing their desktops or applications are outside the network. The situation that causes the most traffic is when both users are outside the network and not leveraging the VPN. In the internal usage scenario, both users are inside the network.

There are a few additional scenarios such as federation sharing, but that traffic is represented in the IM and Presence section of the poster.

The CMS Section

CMS is a repository of XML documents in a back-end SQL Server database. You select which database you want to use as the CMS database when you use the Topology Builder to build your topology. CMS stores the topology data, configurations, and policies that make up the Lync 2013 environment.

As you can see in Figure 5, the poster's CMS section doesn't go into great detail about how CMS works. However, it does show that a CMS replica exists for each of the different server roles. It also illustrates a key CMS concept: The CMS master pool handles communication to the back-end SQL Server database on behalf of the other CMS replicas that exist on other Lync 2013 servers in the environment.

Poster's CMS Section

A Helpful Reference Guide

The Lync Server 2013 Protocol Poster is a helpful reference guide for Lync administrators, implementers, and architects. It gives them the in-depth information they need about the network traffic for key workloads in a Lync Server 2013 deployment.