Route-map

Ref: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008047915d.shtml

• If you use an ACL in a route-map permit clause, routes that are permitted by the ACL are redistributed.
  
• If you use an ACL in a route-map deny clause, routes that are permitted by the ACL are not redistributed.
  
• If you use an ACL in a route-map permit or deny clause, and the ACL denies a route, then the route-map clause match is not found and the next route-map clause is evaluated.
  
  
  
  
  A match or set command in each clause can be missed or repeated several times, if one of these conditions exist:
  
  • • If several match commands are present in a clause, all must succeed for a given route in order for that route to match the clause (in other words, the logical AND algorithm is applied for multiple match commands).
      
    • If a match command refers to several objects in one command, either of them should match (the logical OR algorithm is applied). For example, in the match ip address 101 121 command, a route is permitted if it is permitted by access list 101 or access list 121.
      
    • If a match command is not present, all routes match the clause. In the previous example, all routes that reach clause 30 match; therefore, the end of the route-map is never reached.
      
    • If a set command is not present in a route-map permit clause then the route is redistributed without modification of its current attributes.
      
  Do not configure a set command in a deny route-map clause because the deny clause prohibits route redistribution—there is no information to modify.
  A route-map clause without a match or set command performs an action. An empty permit clause allows a redistribution of the remaining routes without modification. An empty deny clause does not allows a redistribution of other routes (this is the default action if a route-map is completely scanned but no explicit match is found).