North American Network Operators Group

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Re: packet reordering at exchange points

  • From: Richard A Steenbergen
  • Date: Tue Apr 09 16:06:11 2002

On Tue, Apr 09, 2002 at 07:18:35PM +0000, E.B. Dreger wrote:
> 
> > Date: Tue, 09 Apr 2002 11:16:24 -0700
> > From: Paul Vixie <paul@vix.com>
> 
> > my expectation is that when the last mile goes to 622Mb/s or 1000Mb/s,
> > exchange points will all be operating at 10Gb/s, and interswitch trunks
> > at exchange points will be multiples of 10Gb/s.
> 
> I guess Moore's Law comes into play again.  One will need some
> pretty hefty TCP buffers for a single stream to hit those rates,
> unless latency _really_ drops.  (Distributed CDNs, anyone?  Speed
> of light ain't getting faster any time soon...)

To transfer 1Gb/s across 100ms I need to be prepared to buffer at least
25MB of data. According to pricewatch, I can pick up a high density 512MB
PC133 DIMM for $70, and use $3.50 of it to catch that TCP stream. Throw in
$36 for a GigE NIC, and we're ready to go for under $40. Yeah I know thats
cheapest garbage you can get, but this is just to prove a point. :) I 
might only be able to get 800Mbit across a 32bit/33mhz PCI bus, but 
whatever.

The problem isn't the lack of hardware, it's a lack of good software (both
on the receiving side and probably more importantly the sending side), a
lot of bad standards coming back to bite us (1500 byte packets is about as
far from efficient as you can get), a lack of people with enough know-how
to actually build a network that can transport it all (heck they can't
even build decent networks to deliver 10Mbit/s, @Home was the closest),
and just a general lack of things for end users to do with that much
bandwidth even if they got it.

-- 
Richard A Steenbergen <ras@e-gerbil.net>       http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177  (67 29 D7 BC E8 18 3E DA  B2 46 B3 D8 14 36 FE B6)