[nsp] BGP issues after upgrading IOS versions

Scott Lambert scott at inch.com
Tue Aug 26 01:03:30 EDT 2003

On Mon, Aug 25, 2003 at 08:29:12PM -0600, Danny McPherson wrote:
> On Monday, August 25, 2003, at 03:58 PM, Scott Lambert wrote:
> >router bgp 4276
> > no synchronization
> > bgp log-neighbor-changes
> > network mask
> >-ip route Null0 240
> > ip route Null0 255
> When a "network" statement is configured the BGP process checks
> to ensure that a local IP RIB (& FIB) entry exists for the
> concerned *prefix* before generating an update and considering
> the route as feasible.
> In the "working" configuration there was a "hold-down" (or "hold-up",
> depending on who you're talking to :-) route for with
> an administrative distance of 240, which is fine.  It looks as if
> there was also a route for the same prefix with an administrative
> distance of 255 (which means the router doesn't trust the source and
> won't use the route to populate the RIB).
> In the "non-working" configuration the route with the administrative
> distance of 240 is gone and only the "useless" route (i.e., the route
> with the administrative distance of 255) remains.  As such, when BGP
> checks for a RIB match before generating the /19 advertisement it
> fails.

Ah!  That sounds like it could be worth investigating.     

I'm guessing the memory issue could be part of why it is flaking out on
us.  In which case, the IOS upgrade isn't going to help.

Now to try to decide whether to try the upgrade again tonight or wait
for the memory to arrive Wednesday.
> I don't see any obvious indicators in the bug lists for these IOS
> versions that would suggest why the 240 route would be removed, but
> nonetheless, I'd suspect that was at least part of your problem.

Thanks everyone for your replies so far.  They have all been very

Scott Lambert           KC5MLE           System Administrator

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