User's Manual

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Appendix A: Basic call flows

Using SIP as the signaling protocol to establish a communication path

between endpoints, the SIP Application Module provides the following

call services:

• Voice plus video

• Call transfer

• Authentication

The following sections provide sample diagrams and descriptions of the

call flows that enable these specific services. For an overview of a basic

call flow, see the MCP Basics document.

Voice plus video

Figure 1, “Client-to-client voice plus video diagram,”and Figure 2,

“Client-to-client voice plus video call flow,” show the basic call flow for

a client-to-client voice-plus-video call. Each client in the diagram has a

User Agent. The SIP Application Module provides Back-to-Back User

Agent service, treating each SIP call as an independent Ingress and

Egress leg. A detailed, step-by-step illustration follows this diagram.