Chapter 1
Using the Cisco Voice Gateway 200
Using a Cisco VG200 Gateway with H.323
1-8
Software Configuration Guide for the Cisco VG200
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When you use a Cisco VG200 gateway with Cisco CallManager, you can use its
redundant call agent feature to eliminate a potential single point of failure in the
VoIP network. This feature requires that you have two or three Cisco CallManager
servers available on your network and that you identify each of these servers using
CLI commands. You identify the primary Cisco CallManager server as the MGCP
call agent, and identify the second and third Cisco CallManager servers as backup
servers.
Once the redundant call agent feature is configured, if the primary
Cisco CallManager server becomes unavailable, the Cisco VG200 gateway will
register with the backup Cisco CallManager server. The Cisco VG200 gateway
monitors MGCP packets sent by the Cisco CallManager and when no such traffic
is detected, it sends keepalive packets to which the Cisco CallManager server
should respond. If the Cisco VG200 gateway does not detect any packets from the
Cisco CallManager for a specified period, it will try to establish a new connection
with the backup Cisco CallManager server.
Another feature of the Cisco VG200 is called switchback, which refers to the way
that the gateway reestablishes a connection with the primary Cisco CallManager
server when the primary server becomes available again. You can configure the
Cisco VG200 to reestablish connection immediately, or to wait for a specified
length of time to ensure greater stability in the voice network.
Using a Cisco VG200 Gateway with H.323
The Cisco VG200 functions as an H.323 gateway with the following voice
interface types, which are currently not supported with MCGP:
•
E1 (R2 and E&M analog emulation)
•
T1-CAS (FXO, FXS, and E&M emulation)
•
E1-PRI
•
T1-PRI
•
ISDN/BRI
•
E&M
Note that H.323 configuration is more complicated compared to MGCP and does
not provide for redundant call agents. The following sections describe how to use
the Cisco VG200 with H.323 with various interface and signalling types:
