[3438] in North American Network Operators' Group
Re: Ping flooding
daemon@ATHENA.MIT.EDU (Vadim Antonov)
Fri Jul 12 01:07:02 1996
Date: Thu, 11 Jul 1996 21:57:02 +0800
From: avg@ncube.com (Vadim Antonov)
To: alan@gi.net, avg@ncube.com
Cc: herry@westie.gi.net, nanog@merit.edu
If you want to run large network you'd better think about
tools to configure routers and maintain configurations.
In my practice more than 70% of non-link related problems in
corporate networks (and i've seen _lots_ of them) is due to
unnecessary dynamic routing. Just watch some luser turing on
RIP on his itty bitty terminal server or someting and causing
the entire corporation to go banana.
In public Internet, dynamic routing over tail links is downright
antisocial. I hope i don't need to explain _that_.
As an addendum to my remarks -- if you think you have complete
knowledge of how you dynamically routed network behaves in case
of various failures you're deceiving yourself.
The distributed algorithms too often behave counterintuitively,
and implementations often have subtle bugs.
--vadim
From alan@westie.gi.net Thu Jul 11 18:53 PDT 1996
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From: Alan Hannan <alan@gi.net>
Message-Id: <199607120153.UAA11459@westie.gi.net>
Subject: Re: Ping flooding
To: avg@ncube.com (Vadim Antonov)
Date: Thu, 11 Jul 1996 20:53:03 -0500 (CDT)
Cc: herry@westie.gi.net, nanog@merit.edu
In-Reply-To: <9607112000.AA29073@butler.ncube.com> from "Vadim Antonov" at Jul 11, 96 01:00:29 pm
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Status: R
Vadim,
] 2) Don't Do Any Dynamic Routing Where Only One Path Exists.
Certainly I would not agree with this rule.
If I have a tail router that is down, I do not want to send
traffic to him, when he is not there to receive it. Rather, I
would want my intermediate router to reject it right off.
Furthermore, I do not want to extend nondynamic notification in my
network.
------------------------ = ------------------------
Network:
rtra --------+-------+
| |
rtrb --------+ rtrd +--------- rtre ------- rtrf
| |
rtrc --------+-------+
------------------------ = ------------------------
If rtra is down, I do not want rtre to send packets to rtrd to get
to rtra, do I? Wouldn't I prefer them to be stopped ASAP?
Certainly this is a debatable point.
* Another situation is what happens when you renumber networks?
What hapens when you've large number of downstream networks? Do
you really want static routes in rtrf for all networks attached to
rtrs a,b,c,d,e?
What I find, is that in running a "large" network, filtered
dynamic routing is far preferrable to either static leaf nodes, or
unfiltered dynamic routing.
I want my dynamic routing to be binary: what I should get, or
nothing.
-alan
