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Page 36 | Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes
Examples
Example A A route map that matches on a prefix-list and sets the route metrics
1. Create a prefix list that matches just 52.0.0.0/8
awplus(config)#ip prefix-list test1 permit 52.0.0.0/8
2. Then, create a route map to match on this prefix-list, and set the metric of matching routes
to 665:
awplus(config)#route-map test1 permit 1
awplus(config-route-map)#match ip address prefix-list test1
awplus(config-route-map)#set metric 665
3. Configure the route-map to operate on incoming updates from neighbor 45.45.45.46
awplus(config-router)#neighbor 45.45.45.46 route-map test1 in
Example B Match on a prefix-list that denies an entry
1. Create a prefix list that excludes 52.0.0.0/8, then includes all other routes:
awplus(config)#ip prefix-list test2 deny 52.0.0.0/8
awplus(config)#ip prefix-list test2 permit any
2. Create a route map to match on this prefix-list:
awplus(config)#route-map test2 permit 1
awplus(config-route-map)#match ip address prefix-list test2
awplus(config-route-map)#set metric 665
The route map is:
route-map test2, permit, sequence 1
Match clauses:
ip address prefix-list test2
Set clauses:
metric 665
3. Shut down the neighbor, and then bring it up again:
awplus(config-router)# neighbor 45.45.45.46 shutdown
awplus(config-router)# neighbor 45.45.45.46 no shutdown
4. Check the route table. This time, the only route learnt from the peer is 45.0.0.0/8, and it
still has metric 665. The prefix-list has explicitly matched all routes except 52.0.0.0/8, so
all routes except 52.0.0.0/8 have been permitted by the first entry of the route map. Then
52.0.0.0/8 has been denied by the implicit deny-all entry at the end of the route map.
awplus#show ip route