Hello,
upgraded from bird 1.2.4 to bird 1.3.1 last weekend, but needed to revert
due to complaints from high bgp traffic to bgpmon.net and 100% cpu load on
a 2x bird bgp routers setup connected with iBGP.
Did some research, and noticed a high bgp traffic situation on the iBGP
sessions (about 10.000 bgp packets in 1.7 second)
Based on graph statistics, i noticed a irregular traffic on the trans-ip's
as well (noticed after rollback in statistical graphs)
In the logging (mostly on the first bgp router) , i noticed quite some
messages (33414 in ~12h) like:
29-05-2011 10:57:49 <WARN> Next hop address X.X.X.242 resolvable through
recursive route for X.X.X.0/24
29-05-2011 10:57:49 <WARN> Next hop address Y.Y.35.194 resolvable through
recursive route for Y.Y.32.0/19
29-05-2011 10:57:52 <WARN> Next hop address X.X.X.241 resolvable through
recursive route for X.X.X.0/24
29-05-2011 10:57:52 <WARN> Next hop address X.X.X.242 resolvable through
recursive route for X.X.X.0/24
29-05-2011 10:57:55 <WARN> Next hop address Y.Y.35.194 resolvable through
recursive route for Y.Y.32.0/19
29-05-2011 10:57:55 <WARN> Next hop address X.X.X.241 resolvable through
recursive route for X.X.X.0/24
29-05-2011 10:57:55 <WARN> Next hop address X.X.X.242 resolvable through
recursive route for X.X.X.0/24
These are the subnets of the upstream trans-ip links of it's neigbor
router
On the second (neighbor) bgp router, noticed only such 15 recursive
messages
I had those upstream trans-ip interface IP's manually added once to the
bird.conf with a "protocol static" definition with a subnet of /32. I
thought this might be the problem, and wel, disabled those static trans-ip
interface routes, except i forgot one. Noticed a lower CPU afterwards,
but problem persisted, and i reverted to 1.2.4. Later i noticed i missed
one static route to disable, but no time left to upgrade and test again.
I think i should have looked at the recursive routes in bird, but i
didn't.
Does one know what was going on here, and what to do to prevent it when
executing another upgrade?
I created a 10.000 packet tcpdump capture (full size) of an iBGP session,
in case somone would like to look at it.
Regards,
Arjan Filius
--
Arjan Filius
mailto:[email protected]
