Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 110)

82 Multi-Service IronWare Routing Configuration Guide
53-1003033-02
Filtering
• If the route map contains a deny action, a route that matches a match statement is denied.
• If a route does not match any match statements in the route map, the route is denied. This is
the default action. To change the default action, configure the last match statement in the last
instance of the route map to permit any any.
• If there is no match statement, the software considers the route to be a match.
• For route maps that contain address filters, AS-path filters, or community filters, if the action
specified by a filter conflicts with the action specified by the route map, the route map action
takes precedence over the filter action.
If the route map contains set clauses, routes that are permitted by the route map match
statements are modified according to the set clauses.
Match statements compare the route against one or more of the following:
• The route BGP4 MED (metric)
• A sequence of AS-path filters
• A sequence of community filters
• A sequence of address filters
• The IP address of the next hop device
• The route tag
• For OSPF routes only, the route type (internal, external type-1, or external type-2)
• An AS-path ACL
• A community ACL
• An IP prefix list
• An IP ACL
For routes that match all of the match statements, the route map set clauses can perform one or
more of the following modifications to the route attributes:
• Prepend AS numbers to the front of the route AS-path. By adding AS numbers to the AS-path,
you can cause the route to be less preferred when compared to other routes based on the
length of the AS-path.
• Add a user-defined tag an automatically calculated tag to the route.
• Set the community attributes.
• Set the local preference.
• Set the MED (metric).
• Set the IP address of the next-hop device.
• Set the origin to IGP or INCOMPLETE.
• Set the weight.
• Set a BGP4 static network route.
When you configure parameters for redistributing routes into BGP4, one of the optional parameters
is a route map. If you specify a route map as one of the redistribution parameters, the device
matches the route against the match statements in the route map. If a match is found and if the
route map contains set clauses, the device sets the attributes in the route according to the set
clauses.
To create a route map, you define instances of the map by a sequence number.
To define a route map, use the procedures in the following sections.