Mgcp Overview; Configuration For Multiple Call Agents And Gateways - Cisco Catalyst 6500 Series Configuration Manual

Chapter 13 Configuring Application Protocol Inspection

MGCP Overview

Examples of media gateways are:
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MGCP messages are transmitted over UDP. A response is sent back to the source address (IP address
and UDP port number) of the command, but the response may not arrive from the same address as the
command was sent to. This can happen when multiple call agents are being used in a failover
configuration and the call agent that received the command has passed control to a backup call agent,
which then sends the response.

Configuration for Multiple Call Agents and Gateways

Use the following commands to configure the FWSM to support the use of multiple MGCP call agents
and gateways:
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OL-6392-01
Trunking gateways, that interface between the telephone network and a Voice over IP network. Such
gateways typically manage a large number of digital circuits.
Residential gateways, that provide a traditional analog (RJ11) interface to a Voice over IP network.
Examples of residential gateways include cable modem/cable set-top boxes, xDSL devices,
broad-band wireless devices.
Business gateways, that provide a traditional digital PBX interface or an integrated soft PBX
interface to a Voice over IP network.
To specify a group of call agents that can manage one or more gateways, enter the following
command:
FWSM/contexta(config)# mgcp call-agent ip_address group_id
This information is used to open connections for the other call agents than the one a gateway sends
a command to, so that any of the call agents can send the response. The ip_address specifies the IP
address of the call agent. The group_id is a number from 0 to 4294967295. Call agents with the same
group_id belong to the same group.
To specify the maximum number of MGCP commands that can be queued waiting for a response,
enter the following command:
FWSM/contexta(config)# mgcp command-queue limit
The range of allowed values for limit is 1 to 4294967295. The default is 200. When the limit is
reached and a new command arrives, the command that was in the queue for the longest time is
removed.
To specify which group of call agents are managing a particular gateway, enter the following
command:
FWSM/contexta(config)# mgcp gateway ip_address group_id
The IP address of the gateway is specified with the ip_address option. The group_id option is a
number from 0 to 4294967295. It must correspond with the group_id of the call agents that are
managing the gateway.
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide
Detailed Information About Inspection Engines
13-13