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Call Agent

Overview

The Call Agent feature enables the CSP to connect calls with or without bearer paths through the CSP. The CSP can accept requests from SIP clients for a specific host-based voice service and then establish a SIP signaling connection for the requested service.

Call Agent Mode

Call control is resident on the CSP so the RTP stream does not have to pass through the CSP via the VDAC card which avoids "hairpinning" the call. The CSP is now Call Agent mode. You can switch modes and have the RTP stream pass through the VDAC card. The CSP is in VDAC mode.

Figure 1-1 VDAC or Call Agent Mode

Background

Call agent switching technology is driven by the convergence of telecommunication and data networks. Data networks such as IP are typically self-routing and connectionless. Therefore, are more like circuit-switched transport networks.

Refer to the Call Agent chapter for a full explanation of Call Agent in the CSP.

Session-Initiation Protocol. A signaling protocol used for establishing sessions in an IP network. A session could be a simple, two-way telephone call, or it could be a collaborative multi-media conference session.
Real-Time Transport Protocol. Supports transport of real-time data like interactive voice and video over packet-switched networks.
Internet Protocol. Part of the TCP/IP family of protocols used to route messages and tracks the addresses of nodes.