Call Control Function; Figure 3-10 Call Agent Communications Links - Cisco Voice Interworking Services (VISM) Installation And Configuration Manual

Chapter 3 VISM Functional Description

Call Control Function

Call control is used in the switched AAL2 PVC operating mode only and is managed by the call agents.
The call agent performs the following functions:
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These functions require call agent communication with the VISM cards under call agent control and peer
call agents.

Figure 3-10 Call Agent Communications Links

V
The interface between the call agent and VISM cards is a gateway call control protocol generically
known as xGCP. The following gateway call control protocols are supported:
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SRCP enables the VISM card and the call agent to resynchronize. Synchronization occurs when the call
agent first assumes control of VISM or after the call agent loses communication with VISM.
All protocols use a UDP/IP connection between the call agent and the VISM cards. The IP address of
the call agent can be resolved in the following ways:
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You can configure VISM to use the internal table and external DNS in the following ways:
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Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004
Analyzes signaling received from VISM cards and other call agents to monitor the status of all
endpoints and connections.
Signals VISM cards and other call agents to set up and tear down calls.
Reacts to fax, modem, alarm and other line conditions and events.
Maintains a dial plan to locate the remote call agent using the dialed number.
Negotiates profiles and codecs between the called and calling locations.
Figure 3-10 shows the call agent communications links.
Call Agent
C-ISUP
or SS7
IP (xGCP)
V
MGX 8850
with VISM
Media Gateway Control Protocol (MGCP) 0.1 and 1.0
Simple Gateway Control Protocol (SGCP) 1.5
Simple Resource Control Protocol (SRCP)
Internal table which you set up with the CLI
External domain name server (DNS)
Internal table only
External DNS only
Internal first and external second
External first and internal second
Other Call
Signaling
Agents
Network
Other
Packet
MGX 8850s
Network
VISMs
Cisco VISM Installation and Configuration Guide
Call Control Function
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