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Date:      Fri, 16 Jul 1999 20:08:38 -0700 (PDT)
From:      Vincent Poy <vince@venus.GAIANET.NET>
To:        Matthew Dillon <dillon@apollo.backplane.com>
Cc:        "Louis A. Mamakos" <louie@TransSys.COM>, Bill Paul <wpaul@skynet.ctr.columbia.edu>, crypt0genic <crypt0genic@ecad.org>, hackers@FreeBSD.ORG
Subject:   Re: poor ethernet performance? 
Message-ID:  <Pine.BSF.4.05.9907162005320.331-100000@venus.GAIANET.NET>
In-Reply-To: <199907170220.TAA25948@apollo.backplane.com>

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On Fri, 16 Jul 1999, Matthew Dillon wrote:

> :	I know, I'm just wondering how did they get more frequency out of
> :wire of the same size.  I can understand it if the wire was a larger
> :guage.
> 
>     For twisted pair, Less power == less crosstalk.  Plus the higher 
>     bandwidth transceivers use better receivers and better pre-attenuation
>     of the signal. 

	Cross talk is only one of the variables I think... There is
balancing and ACR and how well it can keep a true 100 Ohms to the cable.

>     I'm not sure what the gigabit copper ethernet people are doing, but there
>     are other ways as well. 

	I wonder if any Gigabit ethernet cards exist that uses UTP because
everything seems to be pointing to the fiber direction.

>     Basic ethernet uses baseband which is quite noisy even with the
>     preattenuation, so there was lots of room to go faster.

	Yep, it would have been nice if the original spec was shielded but
anything shielded would have a degrade in signal...  It's the insultaion
whether it is PVC, Teflon or even the new air chambers introduced by
Matthew Bond at Tara Labs using Regtangular Solid Core cable capable of
handling 2.5Ghz.


Cheers,
Vince - vince@MCESTATE.COM - vince@GAIANET.NET           ________   __ ____ 
Unix Networking Operations - FreeBSD-Real Unix for Free / / / / |  / |[__  ]
GaiaNet Corporation - M & C Estate                     / / / /  | /  | __] ]  
Beverly Hills, California USA 90210                   / / / / / |/ / | __] ]
HongKong Stars/Gravis UltraSound Mailing Lists Admin /_/_/_/_/|___/|_|[____]



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