Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Route-maps are a series of commands that contain a matching criterion and action. They change the packets meeting the matching criterion. ACLs and prefix-lists can only drop or forward the packet or traffic while route-maps process routes for route redistribution. For example, use a route-map to filter only specific routes and to add a metric.

• Route-maps also have an implicit deny. Unlike ACLs and prefix-lists where the packet or traffic drops, if a route does not match the route-map conditions, the route does not redistribute.
• Route-maps process routes for route redistribution. For example, to add a metric, a route-map can filter only specific routes. If the route does not match the conditions, the route-map decides where the packet or traffic drops. The route does not redistribute if it does not match.
• Route-maps use commands to decide what to do with traffic. To remove the match criteria in a route-map, use the no match command.
• In a BGP route-map, if you repeat the same match statements; for example, a match metric, with different values in the same sequence number, only the last match and set values are taken into account.

Configure match metric

OS10(config)# route-map hello
OS10(conf-route-map)# match metric 20

View route-map

OS10(conf-route-map)# do show route-map
route-map hello, permit, sequence 10
  Match clauses:
    metric 20

Change match

OS10(conf-route-map)# match metric 30

View updated route-map

OS10(conf-route-map)# do show route-map
route-map hello, permit, sequence 10
  Match clauses:
    metric 30

To filter the routes for redistribution, combine route-maps and IP prefix lists. If the route or packet matches the configured criteria, OS10 processes the route based on the permit or deny configuration of the prefix list.

When a route-map and a prefix list combine:

• For a route map with the permit action:
  • If a route matches a prefix-list set to deny, the route is denied
  • If a route matches a prefix-list set to permit, the route is permitted and any set of actions apply
• For a route map with the deny action:
  • If a route matches a prefix-list set to deny, the route is denied
  • If a route matches a prefix-list set to permit, the route is permitted and any set of actions apply

OS10(conf-router-bgp-neighbor-af)# do show ip prefix-list
ip prefix-list p1:
seq 1 deny 10.1.1.0/24
seq 10 permit 0.0.0.0/0 le 32
ip prefix-list p2:
seq 1 permit 10.1.1.0/24
seq 10 permit 0.0.0.0/0 le 32

OS10(conf-router-bgp-neighbor-af)# do show route-map
route-map test1, deny, sequence 10
Match clauses:
ip address prefix-list p1
Set clauses:
route-map test2, permit, sequence 10
Match clauses:
ip address prefix-list p1
Set clauses:
route-map test3, deny, sequence 10
Match clauses:
ip address prefix-list p2
Set clauses:
route-map test4, permit, sequence 10
Match clauses:
ip address prefix-list p2
Set clauses: