Why filter not work for two cases?

[Владислав Гришин]

I thank you, it seems clearly.

Vladislav Grishin.


-----Original Message-----
From: Ondrej Zajicek [mailto:santiago at crfreenet.org] 
Sent: Thursday, July 08, 2010 5:28 PM
To: ????????? ??????
Cc: bird-users at trubka.network.cz
Subject: Re: Why filter not work for two cases?

On Thu, Jul 08, 2010 at 01:17:45PM +0400, ????????? ?????? wrote:
> My network.
> 
> Bird is used as border router on the standalone server.
> 
> I have a two upstream ISPs from which I accept full view + default route
> over eBGP.
> I have a one downstream ISP to which I announce full view + default route.
> 
> Into my AS a IGP protocol is OSPF.  The L3 switch Cisco 3550 is used on a
> network.
> Bird IP is 10.10.1.2, Cisco 3550 IP is 10.10.1.3.
> 
> To BGP downstream I plan to announce a default route which is exported
from
> the bird static protocol, for stability.
> For OSPF neighbors I plan to announce a default route which is received
from
> the upstream ISPs, since for each operator in the future there will be a
> server.

...

> Why the default route is not exported to OSPF protocol from bird routing
> table after adding 
> 
> route 0.0.0.0/0 via "lo"; 
> 
> in bird.config of static protocol?
> 
> Why filter export_default_route_from_bgp_to_ospf does not work for two
> cases? 

If there are more routes to the same destination, only the best route
is considered for export. If the best route is filtered, then no route
is exported.

If you want to export one default route to the OSPF and a different
one to the downstream BGP, you have to use two routing tables and
a pipe, for example one (master) routing table for upstream BGP
and OSPF and another table for downstream BGP and a static protocol
with a default route. And a pipe that forwards routes from master
to the secondary table, but does not forward default from secondary
to the primary table.

-- 
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."