[12433] in North American Network Operators' Group
Re: I found the missing 30 milliseconds!
daemon@ATHENA.MIT.EDU (Craig A. Huegen)
Tue Sep 16 17:08:16 1997
Date: Tue, 16 Sep 1997 13:41:14 -0700 (PDT)
From: "Craig A. Huegen" <c-huegen@quadrunner.com>
To: "Kent W. England" <kwe@geo.net>
cc: rirving@onecall.net, Vadim Antonov <avg@pluris.com>, nanog@merit.edu
In-Reply-To: <3.0.2.32.19970916130153.0071d3a0@zeus.geo.net>
On Tue, 16 Sep 1997, Kent W. England wrote:
That's all well and everything, but I'll put $5 down that says everyone
here used standard 56-byte ICMP payload for their pings, which makes the
packet less than 100 bytes total.
/cah
==>Everyone;
==>
==>You can't send a packet out an interface until the entire packet has been
==>received on the incoming interface. Now if we assume 1500 byte packets (the
==>new de facto MTU on all modern Internet backbones) and DS-3 pipes, then it
==>takes about 250 microseconds to buffer the pkt on each hop. Since the US
==>internet backbone from coast to coast is about 120 hops, there's your 30
==>milliseconds and Bob's your uncle.
==>
==>Did I do the arithmetic right?
==>
==>--Kent, ever helpful with NANOG metrication
==>;-)
==>
==>Well, back when us old guys were young, switching delay *was* significant.
==>Did I ever show you my p4200?
==>
