When configuring route map, the match and set route map configuration commands are used to define the condition portion of a route map. The match command specifies a criteria that must be matched, and the set command specifies an action that is to be performed if the routing update meets the condition defined by the match command. Here the sequence number of 10 is used. Route map starts with the lowest sequence number and go on with increasing sequence numbers (if exists) till a match is occurred. Once a match occurs, it stops there and performs the match/set statements on the route. If no match occurs, there is an implicit deny at the end and the route is not redistributed or controlled.
The command mode used to configure filtering of routing update traffic from an interface is
Router(config-router)#
To configure filtering on outgoing update traffic, use the distribute-list command : distribute-list <access-list number> out <interface-name>
The route map command syntax is:
route-map <route-map-name> [permit/deny] [sequence_number_1-65535]
Here, the route_map_name is also called as the map tag. It is the text-based route map name. In that the name is logically grouped and unique as well as defined all the route map policies. It is the name which is used to call a route map during the process and redistribution. The deny and permit keywords are always optional and a default keyword is permit.
If a route map is called from the redistribution process, then the keywords are set to permit and a match criteria are met for a route map, a route is redistributed. If a keyword is set to deny, in same criteria, then a route might be denied.
Suppose a route map is called from the policy routing statement, then match criteria is met for route map as well as a keywords are set to permit, then the packets might be policy routed. If a deny keyword is used, hen the packets are forwarded based on the normal route processes.
