BGP: Setting Weight

jpl861 · ‎04-24-2009

Hi,

I read Routing TCP/IP Volume II and it was stated there that when route maps are used to set weights, only the AS_PATH can be matched; individual IP addresses cannot be matched with the "match ip address" command.

However, I saw some implementations that used IP address in route-maps to set the weight. I don't know if this is a revised behavior of "weight".

Is this still true or not? Thanks.

John

Giuseppe Larosa · ‎04-24-2009

Hello John,

there were three options to do this

neigh x.x.x.x weight YYY

that would set to YYY the weight of all routes received by x.x.x.x

neigh x.x.x.x filter-list Z weight YYY

Z is an as path access-list but this has been removed

see

12.1

The weight keyword was removed.

http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp3.html#wp1037204

the third option is that of using a route-map.

Inside the route-map as you have noted you can use different match commands not only match AS-path.

the second option now not available according to documentation was limited to AS paths.

Hope to help

Giuseppe