OSPF: LSA disappeared

[Ondrej Zajicek]

On Wed, Jan 25, 2012 at 03:14:10PM +0100, Bjoern Engels wrote:
> Hi,
> 
> we're running redundant pairs of routers using keepalived for VRRP and
> BIRD for OSPF. (bird-1.3.3 through bird-1.3.6 actually)
> 
> Static routes are configured in BIRD so when keepalived transitions to
> master state it adds ip addresses to a bunch of vlan interfaces and the
> routes' gateways become directly reachable and are being announced.
> 
> Now when I failover from one primary router to a backup router by
> stopping keepalived the interfaces' addresses are being deleted on the
> former master and added to the backup router. 

So the failover would cause removal of these static routes?

> Immediately after such a transition all BIRD routers fill their log
> files periodically with this kind of messages:
> 
> Jan 25 14:47:06 cr4b bird: OSPF: LSA disappeared (Type: 0005, Id: 192.0.2.0, Rt: 10.10.10.170)
> Jan 25 14:47:06 cr4b bird: OSPF: LSA disappeared (Type: 0005, Id: 192.0.2.128, Rt: 10.10.10.170)

I guess these LSAs represents old static routes (Rt: 10.10.10.170 is the
router that removed the static routes), is this true?

Are there any problems with this other than log filling? You could check
using 'show ospf state' and 'show ospf lsadb' whether the old
LSAs/routes are properly removed and the new are properly installed
during failover (and during the failover back to the primary).

> proto/ospf/lsupd.c says this should never happen:
> 
> /* Probably flushed LSA, this should not happen */
> log(L_WARN "OSPF: LSA disappeared (Type: %04x, Id: %R, Rt: %R)",
>   lsr->lsh.type, lsr->lsh.id, lsr->lsh.rt);
> 
> Is this some bug in BIRD or caused by the way we use it?

This is probably some minor bug in LSA flushing, i will check that.

One problem with log filling is that the message is repeated during each
update.


-- 
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."
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