[10758] in North American Network Operators' Group
Re: Internet Backbone Index
daemon@ATHENA.MIT.EDU (Jay R. Ashworth)
Sun Jul 13 20:02:28 1997
Date: Sun, 13 Jul 1997 19:44:06 -0400
From: "Jay R. Ashworth" <jra@scfn.thpl.lib.fl.us>
To: Randy Bush <randy@psg.com>
Cc: "Dorian R. Kim" <dorian@blackrose.org>, nanog@merit.edu
In-Reply-To: <m0wnWoY-0007zWC@rip.psg.com>; from Randy Bush <randy@psg.com> on Sun, Jul 13, 1997 at 03:08:00PM -0800
On Sun, Jul 13, 1997 at 03:08:00PM -0800, Randy Bush wrote:
> There is one significant difference between routed and switched backbones.
> The hops on routed backbones can be seen by end users using tools such as
> traceroute. On switched backbones, the hops are still there, but can not be
> seen by end users. Hence the marketing perception is different though the
> results are really the same.
Actually, from the IP packet's standpoint, no, the results aren't
necessarily the same. It's unlikely, but possible, that a switched
mesh backbone could forward some packets that a routed one couldn't,
due to TTL issues.
Didn't some older kernels set rediculously low TTLs on IP packets?
> The router side could turn the argument. "With a routed backbone, you can
> actually SEE what is happening to your packets. It is not a hidden unknown,
> thus prone to failure you can not diagnose. With routers you know it went
> bad at nqu1. With switches, it just went bad."
It's a problem I'd accept for this amount of debugging flexibility,
though.
Cheers,
-- jra
--
Jay R. Ashworth jra@baylink.com
Member of the Technical Staff Unsolicited Commercial Emailers Sued
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