[c-nsp] BGP neighbor route-map or prefix-list ?

[Adrian Arumugam]

IIRC...

Inbound announcements, order preference for policies applied by router....
1. route-map
2. filter-list
3. prefix-list, distribute-list

Outbound announcements, order preference for policies applied by router....
1. prefix-list, distribute-list
2. filter-list
3. route-map

I know there is a cisco docs reference available to confirm this.......

Be careful though... the router will apply all policies.... route-map first,
then filter-list, then prefix & distribute lists..... so if any of them
contain a deny the prefix will be denied..... if you have all levels applied
to a session (for the life of me I can't think of why you would want to do
this, as route-maps are powerful enough to do nearly everything)..... then
for a prefix to be allowed 'all' of the policies applied to the session must
allow the prefix...

-- A


On Fri, Sep 16, 2011 at 7:06 AM, Jeffrey G. Fitzwater
<jfitz at princeton.edu>wrote:

> I have been using the ( neighbor xxx.xxx.xxx.xxx prefix-lit myPrefix out )
> to control what prefixes we announce to our  ISPs.
>
> I now have a need to do a little more prefix filter control using (
> neighbor xxx.xxx.xxx.xxx route-map myRouteMap out ) .
>
>
> Can I just do all the PREFIX filtering using the ( neighbor xxx.xxx.xxx.xxx
> route-map myRouteMap out )  and remove the ( neighbor xxx.xxx.xxx.xxx
> prefix-lit myPrefix out )?
>
>
> Is there any reason to keep the ( neighbor xxx.xxx.xxx.xxx prefix-lit
> myPrefix out ) bgp command or is it just redundant with the route-map
> command?
>
>
> I just need to do more control on what PREFIXES get advertised to our
> peers.
>
>
>
>
>
> Thanks for any help.
>
>
>
> Jeff Fitzwater
> OIT Network Systems
> Princeton University
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>