BGP - route maps and using the continue clause
When a Route-map is applied to a BGP neighbor peering which references a prefix list with multiple statements, it will evaluate the statements in the prefix list sequentially based on their sequence numbers. If a match is found, the route-map will stop processing the rest of the statements in the prefix list and will apply the corresponding action (permit or deny) defined in the route-map.
If you use the set command after the match statement in a route-map, the set command will be applied only to the prefix that matches the first matched statement in the prefix list. Once a match is found, the route-map will apply the corresponding action of the set command, then stop processing the rest of the statements in the prefix list.
The result is that the first prefix, which is matched, gets the related action applied, but any subsequent configured set statements for other prefixes within the route list/prefix list combination, are not processed.
In order to allow the route map to continue evaluating and processing the subsequent statements even if a match has been made, you can use the continue clause.
More information about how to use route maps with BGP can be found here:
- BGP - Outbound Route Filtering
- BGP applying route maps to prefixes
- BGP Attributes - route map direction
Links:
https://forum.networklessons.com/t/mpls-vpn-extranet-route-leaking/2380/37?u=lagapides
https://forum.networklessons.com/t/mpls-vpn-extranet-route-leaking/2380/38?u=lagapides
https://forum.networklessons.com/t/mpls-vpn-extranet-route-leaking/2380/39?u=lagapides