Brocade Communications Systems ICX 7250 series, Configuration Manual

Page: 176 / 483

– A virtual interface (a routing interface used by VLANs for routing Layer 3 protocol traffic among one another)
– A tunnel number of the next-hop gateway
– A "null" interface. The Layer 3 switch drops traffic forwarded to the null interface.
You can also specify the following optional parameters:
• VRF name - The name of a non-default VRF associated with the destination.
• The metric for the route - The value the Layer 3 switch uses when comparing this route to other routes in the IP route table to
the same destination. The metric applies only to routes that the Layer 3 switch has already placed in the IP route table. The
default metric for static IP routes is 1.
• The administrative distance for the route - The value that the Layer 3 switch uses to compare this route with routes from other
route sources to the same destination before placing a route in the IP route table. This parameter does not apply to routes that
are already in the IP route table. The default administrative distance for static IP routes is 1.
The default metric and administrative distance values ensure that the Layer 3 switch always prefers static IP routes over routes from
other sources to the same destination.
Multiple static routes to the same destination provide load sharing and
redundancy
You can add multiple static routes for the same destination network to provide one or more of the following benefits:
• IP load balancing - When you add multiple IP static routes for the same destination to different next-hop gateways, and the
routes each have the same metric and administrative distance, the Layer 3 switch can load balance traffic to the routes’
destination.
• Path redundancy - When you add multiple static IP routes for the same destination, but give the routes different metrics or
administrative distances, the Layer 3 switch uses the route with the lowest administrative distance by default, but uses another
route to the same destination if the first route becomes unavailable.
Static route states follow port states
IP static routes remain in the IP route table only as long as the port or virtual interface used by the route is available. If the port or virtual
routing interface becomes unavailable, the software removes the static route from the IP route table. If the port or virtual routing interface
becomes available again later, the software adds the route back to the route table.
This feature allows the router to adjust to changes in network topology. The router does not continue trying to use routes on unavailable
paths but instead uses routes only when their paths are available.
The static route is configured on Switch A, as shown in the configuration example following the figure.
FIGURE 14 Example of a static route
The following command configures a static route to 207.95.7.0, using 207.95.6.157 as the next-hop gateway.
device(config)# ip route 207.95.7.0/24 207.95.6.157
Static routes configuration
Brocade FastIron Layer 3 Routing Configuration Guide
176 53-1003903-04