Cabletron Systems 9032578-05 manual Configuring Advanced Routing Policies, Export Policies

Chapter 13: Routing Policy Configuration Guide

In the configuration shown in Figure 19 on page 185, suppose we decide to run RIP Version 2 on network 120.190.0.0/16, connecting routers R1 and R2.

Router R1 would like to export all RIP, interface, and static routes to OSPF.

ip-router policy redistribute from-proto rip to-proto ospf ip-router policy redistribute from-proto direct to-proto ospf ip-router policy redistribute from-proto static to-proto ospf

Router R1 would also like to export interface, static, RIP, OSPF, and OSPF-ASE routes into RIP.

ip-router policy redistribute from-proto direct to-proto rip ip-router policy redistribute from-proto static to-proto rip ip-router policy redistribute from-proto rip to-proto rip ip-router policy redistribute from-proto ospf to-proto rip ip-router policy redistribute from-proto ospf-ase to-proto rip

Configuring Advanced Routing Policies

Advanced Routing Policies are used for creating complex import/export policies that cannot be done using the redistribute command. Advanced export policies provide granular control over the targets where the routes are exported, the source of the exported routes, and the individual routes which are exported. It provides the capability to send different routes to the various route-peers. They can be used to provide the same route with different attributes to the various route-peers.

Import policies control the importation of routes from routing protocols and their installation in the routing database (Routing Information Base and Forwarding Information Base). Import policies determine which routes received from other systems are used by the SSR routing process. Using import policies, it is possible to ignore route updates from an unreliable peer and give better preference to routes learned from a trusted peer.

Export Policies

Advanced export policies can be constructed from one or more of the following building blocks:

•Export Destinations - This component specifies the destination where the routes are to be exported. It also specifies the attributes associated with the exported routes. The interface, gateway or the autonomous system to which the routes are to be redistributed are a few examples of export-destinations. The metric, type, tag, and AS- Path are a few examples of attributes associated with the exported routes.

•Export Sources - This component specifies the source of the exported routes. It can also specify the metric to be associated with the routes exported from this source. The

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