Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 65)

• Standard - the static route consists of the destination network address and network mask, and the IP
address of the next-hop gateway. You can configure multiple standard static routes with the same
metric for load sharing or with different metrics to provide a primary route and backup routes.
• Interface-based - the static route consists of the destination network address and network mask,
and the Layer 3 switch interface through which you want the Layer 3 switch to send traffic for the
route. Typically, this type of static route is for directly attached destination networks.
• Null - the static route consists of the destination network address and network mask, and the "null0"
parameter. Typically, the null route is configured as a backup route for discarding traffic if the primary
route is unavailable.
Static IP route parameters
When you configure a static IP route, you must specify the following parameters:
• The IP address and network mask for the route destination network.
• The route path, which can be one of the following:
‐ The IP address of a next-hop gateway
‐ An Ethernet port
‐ A virtual interface (a routing interface used by VLANs for routing Layer 3 protocol traffic
among one another)
‐ A "null" interface. The Layer 3 switch drops traffic forwarded to the null interface.
You also can specify the following optional parameters:
• 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 so 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.
Static IP route parameters
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