Cabletron Systems SmartSwitch Export Policies, Route-Filter, Export-Destination, Export-Source

Chapter 11: Routing Policy Configuration Guide

It is only possible to restrict the importation of OSPF ASE routes when functioning as an AS border router.

Like the other interior protocols, preference cannot be used to choose between OSPF ASE routes. That is done by the OSPF costs.

Route-Filter

This component specifies the individual routes which are to be imported or restricted. The preference to be associated with these routes can also be explicitly specified using this component.

The preference associated with the imported routes are inherited unless explicitly specified. If there is no preference specified with a route-filter, then the preference is inherited from the one specified with the import-source.

Every protocol (RIP, OSPF, and BGP) has a configurable parameter that specifies the default-preference associated with routes imported to that protocol. If a preference is not explicitly specified with the route-filter, as well as the import-source, then it is inherited from the default-preference associated with the protocol for which the routes are being imported.

Export Policies

Export policies control the redistribution of routes to other systems. They determine which routes are advertised by the Unicast Routing Process to other systems. Every export policy can have up to three components:

•Export-Destination

•Export-Source

•Route-Filter

Export-Destination

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-Source

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.

166 SmartSwitch Router User Reference Manual