Nortel Networks NN47250-500 Configuring and managing IP routes

NN47250-500 (Version 03.01)

To clear the system IP address, use the following command:

Configuring and managing IP routes

The IP route table contains routes that WSS Software uses for determining the interfaces for a WSS’s external communi-

cations. When you add an IP interface to a VLAN that is up, WSS Software automatically adds corresponding entries to

the IP route table.

For destination routes that are not directly attached, you can add static routes. A static route specifies the destination and

the default router through which to forward traffic.You can add the following types of static routes:

• Explicit route—Forwarding path for traffic to a specific destination

• Default route—Forwarding path for traffic to a destination without an explicit route in the route table

A destination can be a subnet or network. If two static routes specify a destination, the more specific route is always

chosen (longest prefix match). For example, if you have a static route with a destination of 10.10.1.0/24, and another

static route with a destination of 10.10.0.0/16, the first static route is chosen to reach 10.10.1.15, because it has the

longer prefix match.

If the IP route table contains an explicit route for a given destination, WSS Software uses the route. Otherwise, WSS

Software uses a default route. For example, if the route table does not have a route to host 192.168.1.10, the WSS uses

the default route to forward a packet addressed to that host. Nortel recommends that you configure at least one default

route.

You can configure a maximum of four routes per destination. This includes default routes, which have destination

0.0.0.0/0. Each route to a given destination must have a unique gateway address. When the route table contains multiple

default routes or multiple explicit routes to the same destination, WSS Software uses the route with the lowest metric

(cost for using the route). If two or more routes to the same destination have the lowest cost, WSS Software selects the

first route in the route table.

WSS Software can use a route only if the route is resolved by a direct route on one of the WSS switch’s VLANs.

Caution! Clearing the system IP address disrupts the features that use the address.

Note. Before you add a static route, use the show interface command to verify that the

switch has an IP interface in the same subnet as the route’s default router (gateway). WSS

Software requires the routes for the interface to resolve the static route. If the switch does

not have an interface in the default router’s subnet, the static route cannot be resolved and

the VLAN:Interface field of the show ip route command output shows that the static route

is down.