Nortel Networks 42C4911 manual What is a Route Map?, # /cfg/l3/rmap

Alteon OS Application Guide

What is a Route Map?

A route map is used to control and modify routing information. Route maps define conditions for redistributing routes from one routing protocol to another or controlling routing informa- tion when injecting it in and out of BGP. Route maps are used by OSPF only for redistributing routes. For example, a route map is used to set a preference value for a specific route from a peer router and another preference value for all other routes learned via the same peer router. For example, the following command is used to define a route map:

>> # /cfg/l3/rmap 1 (Select a route map)

A route map allows you to match attributes, such as metric, network address, and AS number. It also allows users to overwrite the local preference metric and to append the AS number in the AS route. See “BGP Failover Configuration” on page 182.

Alteon OS allows you to configure 32 route maps. Each route map can have up to eight access lists. Each access list consists of a network filter. A network filter defines an IP address and subnet mask of the network that you want to include in the filter. Figure 11-2illustrates the relationship between route maps, access lists and network filters.

174 „ Chapter 11: Border Gateway Protocol 42C4911, January 2007