Subject: Re: 3/50 Ethernet speed
To: None <thorpej@nas.nasa.gov>
From: Scott J. Ellentuch <tuc@valhalla.stormking.com>
List: port-sun3
Date: 05/30/1995 20:50:41
In Jason Thorpe's own words (And I ">_") :
> 
> On Tue, 30 May 1995 13:48:52 -0400 (EDT) 
>  "Scott J. Ellentuch" <tuc@valhalla.stormking.com> wrote:
> 
>  > >  Is that with tcp or udp?  
>  > >
>  > 	TCP
> 
> So, what are your results using udp?
>
	Hmm, lemme check
> 
>  > 	Thats weird, what happened to 10Mbit?
> 
> 10mbits/sec is the _maximum_.  On a typical ethernet segment, utilization is 
> typically around 20-25%. 
>
	Are you telling me that if I have a single piece of coax between 2
machines that I'll only use 20-25% of it?  Why?
>
> After that, collisions start to hurt 
> performance.  If you're on a switched ethernet, where traffic on each leg 
> is minimized by the switch and there are effectively less hosts on the 
> network which want to broadcast at the same time (thus reducing 
> collisions), it's possible to get higher (50% isn't bad) utilization.
>
	To be totally honest, there are 6 ethernet items on the segment
PERIOD.

	1) AIX 320H (Main box)
	2) Sun 3/50 4.1.1. (2nd DNS server - ONLY)
	3) PC w/SMC Ultra (Which only has the drivers loaded, nothing else)
	4) Terminal server (With no modems in it!)
	5) NCR X-Terminal (off 99.1% of the time)
	6) Fibre transceiver -> FO cable -> FO transceiver - > router to net
>
> So, if you stop to really think about it, 2mbits/sec, which is about 20% 
> utilization, isn't terribly bad for a non-switched ethernet.
>
	Then what your saying is I need more equipment to be more active to
totally use my 10M effectively, and the same with the 56K?


			Tuc / More confused now than EVER!

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