[c-nsp] ISIS Route Flapping Issue

[Peter Rathlev]

On Thu, 2008-11-06 at 09:48 -0500, David Jacobs wrote:
> When I do a "sh spf-log" this is the message I keep seeing
> 
> On Cisco
> 
> 00:24:50      72    109      8      router1.00-00  TLVCONTENT
> 00:24:20      72    109      8      router1.00-00  TLVCONTENT
> 00:23:50      76    109      8      router1.00-00  TLVCONTENT
> 00:23:20      64    109      8      router1.00-00  TLVCONTENT
> 00:22:50      76    109      8      router1.00-00  TLVCONTENT
> 00:22:20      72    109      8      router1.00-00  TLVCONTENT
> 00:21:50      72    109      8      router1.00-00  TLVCONTENT
> 00:21:20      72    109      8      router1.00-00  TLVCONTENT
> 00:20:50      72    109      8      router1.00-00  TLVCONTENT
> 00:20:19      72    108      7      router1.00-00  TLVCONTENT
> 00:19:49      72    108      8      router1.00-00  TLVCONTENT
> 00:19:19      68    108      8      router1.00-00  TLVCONTENT

This is from a neighboring router, right? 

It seems the router is sending out LSP TLV changes, and rather many of
them. In each 30 second interval the router sent 8 TLV changes, about
one every four seconds.

What does "show isis lsp-log" say on "router1"?

> and on Foundry
> 
> 1m55s   450ms   78    6   router1.00-00     Area Address TLV Change
> 2m26s   450ms   39   17   router1.00-00     Area Address TLV Change
> 2m56s   450ms   39   17   router1.00-00     Area Address TLV Change
> 3m27s   450ms   39   13   router1.00-00     Area Address TLV Change
> 3m57s   450ms   39   18   router1.00-00     Area Address TLV Change

I don't know Foundry, but I could be tempted to read this as "Area ID
changed".

> > A shot in the dark, but you wouldn't happen to have another box with
> > the same NET on your network?
> 
> I thought of that as well, But I compared all of the other NET
> address's and they are pretty unique. And correct me if i'm wrong, but
> if there was another router running ISIS with the same NET address
> wouldn't it come up with an error like..
> 
> %CLNS-4-BADPACKET: ISIS: LAN L2 hello, Duplicate system
> ID detected from (duplicate NET address)

That sounds reasonable.

> I forget if there is a command to view all NET address's in the database

That would be "show isis hostname".

Regards,
Peter