Dell Brocade DCX, Configuration Manual

Page: 264 / 1436

192 BigIron RX Series Configuration Guide
53-1001810-01
Configuring forwarding parameters
7
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’s destination network.
•
The route’s 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 device drops traffic forwarded to the null interface.
The following parameters are optional:
•
The route’s metric – The value the device 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 device has
already placed in the IP route table. The default metric for static IP routes is 1.
•
The route’s administrative distance – The value that the device 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 device 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
device can load balance traffic to the routes’ destination. For information about IP load
balancing, refer to
“Configuring IP load sharing” on page 201.
•
Path redundancy – When you add multiple static IP routes for the same destination, but give
the routes different metrics or administrative distances, the device uses the route with the
lowest administrative distance by default, but uses another route to the same destination of
the first route becomes unavailable.
See the following sections for examples and configuration information:
•
“Configuring load balancing and redundancy using multiple static routes to the same
destination”
on page 196
•
“Configuring standard static IP routes and interface or null static routes to the same
destination”
on page 197
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.