Spanning tree melt down ?

Vadim Antonov avg at
Sun Dec 1 08:35:35 UTC 2002

On Fri, 29 Nov 2002, Stephen Sprunk wrote:

> This is a bit of culture shock for most ISPs, because an ISP exists to serve
> the network, and proper design is at least understood, if not always adhered
> to.  In the corporate world, however, the network and support staff are an
> expense to be minimized, and capital or headcount is almost never available
> to fix things that are "working" today.

I think you are mistaken.  In most "ISPs" engineers are considered an
unfortunate expense, to be reduced to bare bone minimum (defined as the
point where network starts to fall apart, and irate customers reach CEO
through the layers of managerial defenses).  Proper design of corporate
networks is understood much better than that of backbones (witness the
unending stream of new magic backbone routing paradigms, which never seem
to deliver anything remotely as useful as claimed), so the only
explanation for having 10+ hops in spanning tree is plain old

> It didn't take 4 days to figure out what was wrong -- that's usually
> apparent within an hour or so.  What takes 4 days is having to reconfigure
> or replace every part of the network without any documentation or advance
> planning.

> My nightmares aren't about having a customer crater like this -- that's an
> expectation.  My nightmare is when it happens to the entire Fortune 100 on
> the same weekend, because it's only pure luck that it doesn't.

Hopefully, not all of their staff is sold on the newest magical tricks
from OFRV, and most just did old fashioned L-3 routing design.


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