Amer Networks E5Web GUI - Manual (Page 263)

Tip: Understanding output from the routes command
For detailed information about the output of the CLI routes command, refer to the
separate CLI Reference Guide.
4.2.3. Route Failover
Overview
Clavister Security Gateways are often deployed in mission-critical locations where availability and
connectivity is crucial. For example, an enterprise relying heavily on access to the Internet could
have operations severely disrupted if a single connection to the external Internet via a single
Internet Service Provider (ISP) fails.
It is therefore not unusual to have backup Internet connectivity using a secondary ISP. The
connections to the two service providers often use different routes to avoid a single point of
failure.
To allow for a situation with multiple ISPs, cOS Core provides a Route Failover capability so that
should one route fail, traffic can automatically failover to another, alternate route. cOS Core
implements route failover through the use of Route Monitoring in which cOS Core monitors the
availability of routes and then switches traffic to an alternate route should the primary, preferred
route fail.
Figure 4.3. A Route Failover Scenario for ISP Access
Setting Up Route Failover
To set up route failover, Route Monitoring must be enabled and this is an option that is enabled
on a route by route basis. To enable route failover in a scenario with a preferred and a backup
route, the preferred route will have route monitoring enabled, however the backup route does
not require this since it will usually have no route to failover to. When route monitoring is
enabled for a route, one of the following monitoring methods must be chosen:
Interface Link Status cOS Core will monitor the link status of the interface specified in
the route. As long as the interface is up, the route is diagnosed
Chapter 4: Routing
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