Bird Preference and OSPF

Matthew V. Weigl mweigl at usa.net
Thu May 5 17:11:33 CEST 2005


I'm running bird on a Linksys WRT54G running Sveasoft Talisman 1.0.1 firmware. 
Bird version is 1.0.11, and it is part of that firmware, so I am not sure how 
it was built.

I want my WRT to advertise 0.0.0.0/0 as long as the WAN port is up. I have 
another system (Linux w/Quagga) running which provides another default route. 
I've got a Cisco router on the same net which peers, but does not send a 
default. I've made the Linux system's default a higher metric.

o---------------------------------o 172.16.1.0/24
    |             |              |
WRT54G       Cisco 2610       Linux
  Bird         12.2(28a)    Quagga OSPFd
    |            |||             |
Internet     Other Nets      Internet
(NATed)                      (NATed)

Default routes come from redistributing kernel on quagga (E2 w/cost 20000), and 
export all on bird (E2 w/cost 10000).

I ran into trouble where the higher metric default (from Quagga) would 
overwrite the local default on the WRT, which I determined was based on 
preference of protocols within bird (kernel < ospf). I adjusted the preferences 
to the order that I wanted, and I am now unable to peer with quagga or Cisco 
routers. Debug on Cisco shows continual resending of DBD packets, stuck in 
EXSTART. Cisco docs show that it's likely an MTU size mismatch, however 
ifconfig on my WRT and sh int on my Cisco match MTU's. The quagga ospfd comes 
up with some similar error, however I'm not as familiar with it's debug output. 
The great part is that if I remove my protocol preferences in bird, the peering 
works (but stomps my default route).

I am looking for any insight that anyone may have on this issue. Any responses 
are appreciated.

Here's my bird.conf...

router id 172.16.1.12;

protocol kernel {
preference 50;
learn;
persist;
scan time 10;
import all;
export all;
}
protocol device {
scan time 10;
}
protocol direct {
interface "*";
}
protocol ospf WRT54G_ospf {
preference 100;
export all;
area 0 {
interface "br0" { cost 10; };
interface "vlan1" { cost 10; stub yes; };
};
}

--
Matt Weigl



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