nanog mailing list archives
Re: I found the missing 30 milliseconds!
From: "Jay R. Ashworth" <jra () scfn thpl lib fl us>
Date: Tue, 16 Sep 1997 17:46:26 -0400
On Tue, Sep 16, 1997 at 01:01:53PM -0700, Kent W. England wrote a treatise which identified the Rose Mary Woods of the Internet, or so he thought...:
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?
I think you did the math right... but isn't that what "cut-through" switching is all about? Sending the packet out before you're done getting it in? Cheers, -- jra -- Jay R. Ashworth jra () baylink com Member of the Technical Staff Unsolicited Commercial Emailers Sued The Suncoast Freenet "People propose, science studies, technology Tampa Bay, Florida conforms." -- Dr. Don Norman +1 813 790 7592
Current thread:
- Re: ATM (was Re: too many routes), (continued)
- Re: ATM (was Re: too many routes) Randy Bush (Sep 18)
- Re: ATM (was Re: too many routes) Tim Pozar (Sep 15)
- Re: ATM (was Re: too many routes) Sean M. Doran (Sep 11)
- Re: ATM (was Re: too many routes) Vadim Antonov (Sep 11)
- Re: ATM (was Re: too many routes) Nathan Stratton (Sep 12)
- Re: ATM (was Re: too many routes) Richard Irving (Sep 12)
- Re: ATM (was Re: too many routes) Vadim Antonov (Sep 12)
- Re: ATM (was Re: too many routes) Richard Irving (Sep 12)
- I found the missing 30 milliseconds! Kent W. England (Sep 16)
- Re: I found the missing 30 milliseconds! Craig A. Huegen (Sep 16)
- Message not available
- Re: I found the missing 30 milliseconds! Jay R. Ashworth (Sep 16)
- Re: I found the missing 30 milliseconds! Taner Halicioglu (Sep 16)
- Re: I found the missing 30 milliseconds! Kent W. England (Sep 17)
- Re: ATM (was Re: too many routes) Robert E. Seastrom (Sep 12)
- Re: ATM (was Re: too many routes) Michael Dillon (Sep 12)
- Re: ATM (was Re: too many routes) Dorian R. Kim (Sep 12)
- Re: ATM (was Re: too many routes) Tony Li (Sep 12)
- Re: ATM (was Re: too many routes) Paul Traina (Sep 12)
- Re: ATM (was Re: too many routes) Steve Goldstein (Sep 12)
- Re: ATM (was Re: too many routes) Sean M. Doran (Sep 14)
- Re: ATM (was Re: too many routes) Paul Traina (Sep 14)