[c-nsp] 7200 T1 Aggregator - ~30-40 LSA events/sec. Normal?

[Matt Stockdale]

Found it.

Someone didn't follow the procedure and used the /30 referenced in the
LSA on a T1. When LSA's duel, everyone looses.

Looks like today is wild goose chase day.

Matt

On Thu, 2006-04-27 at 18:49 -0400, Matt Stockdale wrote:
> My initial investigation with flood debug shows that this router is
> receiving this LSA on fa0/0 from both the DR and the BDR, and sending
> out about 170 Type 2 Acks back out the same interface to the multicast
> ospf address within 5 seconds.
> 
> It also shows that the "Advertising Router" from the flooding LSA's just
> isn't sending these out - I watched for 2 or 3 minutes and didn't see it
> send this. (Which makes sense, the Link the LSA is describing is
> stable.)
> 
> Since this router has only one ethernet interface, and that
> interface/network is the only one OSPF is running on (really for the
> sole purpose of advertising the T1 netblocks to the rest of our
> network), Why would it be sending out LSA's from another router? In
> theory, any update that comes in over fa0/0 is going to every other host
> on that network already. I guess my OSPF-fu is a little weak, but that
> doesn't seem smart to me..
> 
> Matt
> 
> -----Original Message-----
> From: Rodney Dunn [mailto:rodunn at cisco.com] 
> Sent: Thursday, April 27, 2006 4:57 PM
> To: Matt Stockdale
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] 7200 T1 Aggregator - ~30-40 LSA events/sec. Normal?
> 
> debug ip ospf flood
> 
> 
> You can configure ip ospf flood-reduction if all the routers in the
> network support DC.
> 
> 
> On Thu, Apr 27, 2006 at 04:33:12PM -0400, Matt Stockdale wrote:
> > Hmm. It looks like when I took a tcpdump sample earlier, I managed to 
> > grab the LSA's for the static route during their normal retransmit. It
> 
> > looks like the ongoing flood of LSA's is coming from somewhere else, 
> > and being passed along. I'll keep investigating.
> > 
> > Matt
> > 
> > On Thu, 2006-04-27 at 14:50 -0400, Matt Stockdale wrote:
> > > Folks -
> > > 
> > >   I've just noticed that our 7206VXR, NPE-400, 12.1.19(E1), is 
> > > sending out ~30-40 LSA packets per second on the ethernet port that 
> > > is the only link to our core. Now, this router runs 4 channelized T3
> 
> > > cards for T1 aggregation, and redistributes static and connected (85
> 
> > > and 44 routes, repsectively). None of the downstream routers on the 
> > > T1 are configured for OSPF. (at least, they shouldn't be), and the 
> > > circuits aren't bouncing.
> > > 
> > >   A quick debug session shows that the LSA's are for the static and 
> > > connected routes.
> > > 
> > >   Is this normal? I see that I can configure some LSA throttling, 
> > > but it's hard to figure out the right value to throttle at if I'm 
> > > not sure why this is happening in the first place..
> > > 
> > >   Flames pointing me to RTFM welcome, as long as the TFM is
> specified.
> > > 
> > > Thanks in advance,
> > >   Matt
> > > 
> > > --
> > > Matt Stockdale
> > > Network Engineer
> > > Logicworks
> > > 
> > >   
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> 
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