Usage of ripd's route-map support.
Optional argument route-map MAP_NAME can be added to each redistribute
statement.
redistribute static [route-map MAP_NAME] redistribute connected [route-map MAP_NAME] .....
Cisco applies route-map _before_ routes will exported to rip route table. In current Quagga's test implementation, ripd applies route-map after routes are listed in the route table and before routes will be announced to an interface (something like output filter). I think it is not so clear, but it is draft and it may be changed at future.
Route-map statement (see Route Map) is needed to use route-map functionality.
This command match to incoming interface. Notation of this match is different from Cisco. Cisco uses a list of interfaces - NAME1 NAME2 ... NAMEN. Ripd allows only one name (maybe will change in the future). Next - Cisco means interface which includes next-hop of routes (it is somewhat similar to "ip next-hop" statement). Ripd means interface where this route will be sent. This difference is because "next-hop" of same routes which sends to different interfaces must be different. Maybe it'd be better to made new matches - say "match interface-out NAME" or something like that.
Match if route destination is permitted by access-list.
Cisco uses here <access-list>, ripd IPv4 address. Match if route has this next-hop (meaning next-hop listed in the rip route table - "show ip rip")
This command match to the metric value of RIP updates. For other protocol compatibility metric range is shown as <0-4294967295>. But for RIP protocol only the value range <0-16> make sense.