Dell BigIron RX Series, Руководство по настройке

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200 BigIron RX Series Configuration Guide
53-1002253-01
Configuring forwarding parameters
7
•
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 203
•
“Configuring standard static IP routes and interface or null static routes to the same
destination”
on page 204
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.
This feature allows the device to adjust to changes in network topology. The device does not
continue trying to use routes on unavailable paths but instead uses routes only when their paths
are available.
Figure 10 shows a network containing a static route. The static route is configured on Router A, as
shown in the CLI following the figure.
FIGURE 10 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.
BigIron RX(config)# ip route 207.95.7.0/24 207.95.6.157
When you configure a static IP route, you specify the destination address for the route and the
next-hop gateway or device interface through which the device can reach the route. The device
adds the route to the IP route table. In this case, Router A knows that 207.95.6.157 is reachable
through port 1/2, and also assumes that local interfaces within that subnet are on the same port.
Router A deduces that IP interface 207.95.7.188 is also on port 1/2.
The software automatically removes a static IP route from the IP route table if the port used by that
route becomes unavailable. When the port becomes available again, the software automatically
re-adds the route to the IP route table.
207.95.7.69/24
207.95.7.7/24
Router B
Router A
207.95.6.188/24
207.95.6.157/24
e 1/2