[67154] in North American Network Operators' Group
Re: Strange public traceroutes return private RFC1918 addresses
daemon@ATHENA.MIT.EDU (Leo Bicknell)
Tue Feb 3 14:13:53 2004
Date: Tue, 3 Feb 2004 14:12:58 -0500
From: Leo Bicknell <bicknell@ufp.org>
To: Petri Helenius <pete@he.iki.fi>
Cc: Niels Bakker <niels=nanog@bakker.net>, nanog@merit.edu
Mail-Followup-To: Petri Helenius <pete@he.iki.fi>,
Niels Bakker <niels=nanog@bakker.net>, nanog@merit.edu
In-Reply-To: <401FEB16.5030903@he.iki.fi>
Errors-To: owner-nanog-outgoing@merit.edu
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In a message written on Tue, Feb 03, 2004 at 08:40:22PM +0200, Petri Heleni=
us wrote:
> If you're paying for 40 byte packets anyway, there is no incentive to=20
> ever go beyond 1500
With a 20 byte IP header:
A 40 byte packet is 50% data.
A 1500 byte packet is 98.7% data.
A 9000 byte packet is 99.7% data.
Anyone who pays by the bit should like large packets better than
small packets, as you pay for less "overhead" bandwidth.
Note that a 1500 byte IP in IP packet becomes 1520, and then gets
fragmented to 1500 and a 40 byte packet (20 data, 20 header). That's
only 97.3% efficient, where as a single 1520 byte packet, if it
could be carried, is 98.7% efficient.
Obviously talking in smaller numbers, but to a lot of VPN vendors
1.4% improvement in bandwidth usage, bus usage, or avoiding the
path through the device that fragments a packet in the first place
is a big win.
--=20
Leo Bicknell - bicknell@ufp.org - CCIE 3440
PGP keys at http://www.ufp.org/~bicknell/
Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org
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