Hi -

The inactive timer is (I presume) the OSPF dead-timer expiring.  If so (and if 
set to defaults) it means that e.f.g.h didn't receive an OSPF hello for 40 
seconds from a.b.c.d.


a.b.c.d discovering that e.f.g.h is in one-way state probably happened 
immediately after e.f.g.h decided a.b.c.d was dead.  I guess a.b.c.d still 
thought the neighbour relationship was still full, which means that either the 
problem with hello packets being received only affected one neighbour, or that 
a.b.c.d's timer hadn't expired.

Presumably the chronology is something like this:

1. e.f.g.h doesn't get hellos from a.b.c.d

2. a.b.c.d may still be getting e.f.g.h's hellos, so hasn't timed-out the 
neighbour relationship

2. e.f.g.h's inactive timer expires, and decides a.b.c.d is dead

3. e.f.g.h clears the neighbour state internally

4. e.f.g.h sends a hello and goes into one-way, waiting for neighbours to let 
themselves be known

5. a.b.c.d receives the new hello which no longer contains his RID, and clears 
his neighbour state to start afresh.


Sounds to me like a layer-2 issue that affected OSPF hello reception on e.f.g.h 
somehow.  Broadcast storm or ARP poisoning of a.b.c.d's address maybe?

Just a few random thoughts.....

Andrew

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: 28 March 2008 16:39
To: Farhan Jaffer
Cc: [EMAIL PROTECTED]; juniper-nsp@puck.nether.net
Subject: Re: [j-nsp] OSPF neighbor Down :: without reason

This looks like a physical layer problem.  Maybe not a link flap per se but 
some sort of media issue.  I'm not familiar with the inactive timer though so I 
don't know what the first message means exactly.  The one-way message seems 
kind of odd as well.  Your neighbor declared you dead before you did the same.  
The route only noticed because the neighbor sent a hello without it's router id 
in the list of known routers.  What kind of link is connecting the two routers? 
 Is it frame-relay or sonet?  It seems like there was a link failure that 
didn't lead to an interface flap.  Are there any errors on your sh int <> 
extensive?  Also how often does this happen.



> On 3/24/08, Farhan Jaffer <[EMAIL PROTECTED]> wrote:
> > One side:
> > rpd[3120]: RPD_OSPF_NBRDOWN: OSPF neighbor a.b.c.d state changed
> > from Full to Down due to InActiveTimer (event reason: neighbor was
> > inactive and declared dead)
> >
> > Other side:
> > rpd[3055]: RPD_OSPF_NBRDOWN: OSPF neighbor e.f.g.h state changed
> > from Full to Init due to 1WayRcvd (event reason: neighbor is in
> > one-way
> > mode)
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