input filter to set outgoing prefferences
santiago at crfreenet.org
Thu Jun 10 14:13:27 CEST 2010
On Thu, Jun 10, 2010 at 09:57:59AM +0200, Arjan Filius wrote:
> Hello bird-users,
> (email send in html to prevent text wrapping, .txt version attached)
> running bird 1.2.3 ppa x64 ubuntu 10.04LTS. 2 bird routers connected with
> 2 iBGP sessions over different links.
> I'm trying to route specific outgoing traffic over a specific Transit.
> It starts with that I'm not really sure how to do it, so tested a bit.
> Setting Local performance
> on protocol definition works just fine for a complete Transit, however
> when i want to do it more fine grained, i run into trouble.
You mean local preference (LOCAL_PREF BGP attribute)? You can set local
preference in filters for specific routes like other attributes (using
'bgp_local_pref'). That would probably do what you want.
> First started with prepending routes in bgp input filter with my own AS,
> which works OK on a single bird router, however, with iBGP all prepended
> local AS-es are stripped, and that concept doesn't work.
You can also prepend peer AS on incoming routes. If you keep such routes
in your AS it should be OK.
> Then, started to set the preference in the bgp input filter, which also
> works fine on a single bird router, but that preference seems not to
> propagate to the second iBGP router.
Yes, (protocol) preference is not BGP attribute, but it is internal BIRD
metric to be able to compare routes from different protocols (BGP/OSPF/static
Protocol preference (route attribute 'preference') and BGP local preference
(route attribute 'bgp_local_pref') are different concepts.
Elen sila lumenn' omentielvo
Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 197 bytes
Desc: Digital signature
More information about the Bird-users