Creating Multiple Forwarding Solutions with IP Policy Lists

By default, the router uses a single route table lookup to determine the forwarding solution for packets. For IP policy lists only, the forward command enables you to configure one or more unique forwarding solutions (interfaces or next-hop addresses) that override the route table lookup. By creating a group of forwarding solutions, you can ensure that there is a reachable solution for the packets.

You can use the order keyword to specify the order of the group of forwarding solutions within a single forward rule. If no order value is specified, then the default order of 100 is assigned to a solution. The router evaluates the forwarding solutions in the group, starting at the solution with the lowest order value, and then uses the first reachable solution. To be considered a reachable solution, a solution must be a reachable interface or a next-hop address that has a route in the routing table. If no solutions are reachable, the traffic is dropped.

The following guidelines apply when you create a group of forwarding solutions in an IP policy list:

In the following sample classifier group of a policy list, the forwarding solution of ATM interface 0/0.1 has the lowest order value in the group, and would therefore be selected as the solution for the policy list. However, if this interface is not reachable, the router then attempts to use the solution with the next higher order; which would be ATM interface 12/0.1. If none of the solutions in the group is reachable, the traffic is dropped.

host1(config-policy-list)#classifier-group westfordClacl precedence 200host1(config-policy-list-classifier-group)#forward interface atm 0/0.1 order 10host1(config-policy-list-classifier-group)#forward interface atm 12/0.1 order 50host1(config-policy-list-classifier-group)#forward interface atm 3/0.25 order 300

Note: You can use the suspend version of the command to suspend an individual entry in a group of forwarding solutions. The forward rule remains active as long as there is a reachable or active entry in the group of forwarding solutions. If you suspend all entries in the group, the status of the forward rule is changed to suspended.

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