Reference Guide

• After a route matches a lter, the lter’s action applies and no additional lters apply to the route
Use prex-lists in processing routes for routing protocols such as OSPF, RTM, and BGP.
To congure a prex-list, use commands in PREFIX-LIST and ROUTER-BGP modes. Create the prex-list in PREFIX-LIST mode and assign
that list to commands in ROUTER-BGP modes.
Route-maps
Route-maps are composed of a series of commands that contain a matching criterion and an action — route-maps can change the
packets meeting the matching criterion. ACLs and prex-lists can only drop or forward the packet or trac. Route-maps process routes for
route redistribution. For example, a route-map can be used to lter only specic routes and to add a metric.
Route-maps also have an implicit deny. Unlike ACLs and prex-lists where the packet or trac is dropped, in route-maps if a route does not
match any of the route-map conditions, the route is not redistributed.
ACLs and prex-lists can only drop or forward trac while route-maps process routes for route redistribution. For example, a route-map
can lter only specic routes to add a metric. The route-map decides where the packet or trac drops if the route does not match any of
the conditions — the route is not redistributed if it does not match.
Route-maps use commands to decide what to do with trac. Use the no match command to remove the match criteria in a route-map.
In a BGP route-map, if you repeat the same match statements (such as match metric) with dierent values in the same sequence number,
only the last match and set values may be taken into account in the route-map processing.
Congure match metric
OS10(config)# route-map hello
OS10(conf-route-map)# match metric 20
OS10(conf-route-map)# do commit
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
OS10(conf-route-map)# do commit
View updated route-map
OS10(conf-route-map)# do show route-map
route-map hello, permit, sequence 10
Match clauses:
metric 30
You can combine route-maps and IP prex-lists to lter the routes for redistribution. If the route or packet matches the congured criteria,
the OS10 device processes the route based on the permit or deny conguration of the prex-list.
Actions performed when a route-map is combined with a prex-list:
• For a route map with permit action:
• If a route matches a prex-list set to deny, the route is denied
• If a route matches a prex-list set to permit, the route is permitted and any set of actions are applied
• For a route map with deny action:
• If a route matches a prex-list set to deny, the route is denied
Access Control Lists
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