Avaya G430 Manual page 260

WAN interfaces
location. The modem cannot do both at the same time. For information about remote access
to the Branch Gateway via modem, see
Finally, IP routing must be configured so that traffic to and from the site uses the Dialer interface
when the primary interface is down. The Dialer interface can work both with static and dynamic
routing (OSPF and RIP). Note that the latter mandates the use of unnumbered IP interfaces.
For information about unnumbered IP interfaces, see
page 426.
Note:
Modem dial backup has complex interactions with other configuration modules within the
Branch Gateway and on your network. Before configuring modem dial-backup, Avaya
recommends reading Application Note - VoIP Network Resiliency. This document discusses
the issues of network design for maximum resiliency, capacity planning for optimum
performance, configuration options for network devices, strategies for implementing routing
across the network, and security concerns. Based on your existing network design, several
redundancy scenarios featuring modem dial backup are available. See
interactions with other features
required for an effective backup scenario for your VoIP installation.
Note:
Modem dial backup does not support backup dial-ins or callbacks. Some backup
configurations require the remote host to receive a request for connection, acknowledge,
end the connection, and dial back the requester. This configuration is not supported.
Related topics:
Typical installations
Prerequisites for configuring modem dial backup
Configuring modem dial backup
Modem dial backup interactions with other features
Configuration example
Modem dial backup maintenance
Typical installations
The Branch Gateways were designed for small branch offices of a larger enterprise.
Consequently, the same RAS may serve many branch offices, and, therefore, many Branch
Gateways. A reasonable assumption is that not all branch offices would need modem dial
backup at the same time. Therefore, the ratio of modem channels at the RAS to Branch
Gateways at branch offices can be less than 1:1. There are several practical ways to configure
the RAS server for use with modem dial backup Dialer interfaces:
• The RAS can assign an IP address to the calling Branch Gateway. This requires the RAS
to identify the call gateway using the PAP/CHAP username, and install an appropriate
260 Administering Avaya G430 Branch Gateway
CLI access using modems
on page 264 for brief discussions of the various features
on page 260
on page 261
on page 266
on page 270
Comments? infodev@avaya.com
on page 31.
Unnumbered IP interfaces
on page 261
on page 264
on
Modem dial backup
October 2013