IOS Configuration: Route Maps

Route maps are an advanced alternative to simple ACLs, and are used for:

• Controlling route redistribution - Can permit or deny routes, or change metrics
• Policy-based routing - Allows for more complex routing decisions
• Additional granularity in NAT - Can define arbitrary address mappings opposed to the normal static mappings
• Defining network policy - Used by BGP

Route maps are structured and processed similar to ACLs.

Each route map statement has a sequence number and is configured to either permit or deny traffic.

If a match condition is met, zero or more set parameters are acted upon.

Like ACLs, route maps end with an implicit deny any.

Route map structure:

• route-map
  • {match | set} <condition>
  • ...
• ...

Configuration

Router(config)# route-map <name> [{permit | deny} [<sequence number>]]
Router(config-route-map)# {match | set } <condition>

match conditions used in redistribution:

• match interface
• match ip address [ACL]
• match ip next-hop
• match ip route-source
• match metric
• match route-type
• match tag

set operations used in redistribution:

• set level {level-1 | level-2 | level-1-2 | stub-area | backbone} (OSPF/IS-IS)
• set metric
• set metric-type {internal | external | type-1 | type-2}
• set tag <value>

Implementing route maps for redistribution:

Router(config-router)# redistribute <protocol> [process ID] route-map <name>

Monitoring

• show ip protocol
• show ip route
• show route-map