[e2e] on local ethernet throughput?

[Dan HE]

"David P. Reed" wrote:
> 
> At 09:33 PM 10/21/2001 -0700, Cannara wrote:
> >What Vernon says is quite right and I'll only add that Collision sensing and
> >recovery happens in times on the order of 200 uS to a few mS, on even
> >extremely highly contended Ethernet segments (many stations ready with pkts to
> >send all the time).  This is far faster than Token passing (many mS), in any
> >of its forms, as a very pertinent graph from the original IEEE 802
> >standarization simulations shows (it can be faxed to anyone who wishes a
> >copy).  This graph is particularly telling in that CSMA/CD become better in
> >relation to Token as the number of contending nodes increases -- yes, better.
> 
> I'd love to see the chart - but can you make a scanned image on a server,
> and send the URL (why fax it?).
> 
> Token rings introduced essentially one bit/node of propagation delay
> (actually slightly less), plus 8 bits of token overhead at the end of each
> packet.  At 10 Mbit/sec, that is hardly "many mS", if you have only
> hundreds of nodes on the ring (as N grows, you can make it as large as you
> like).  You are absolutely right that the corresponding "arbitration time"
> for CSMA/CD Ethernet is flat with regards to the number of nodes.  It
> actually grows with the diameter of the collision domain due to "speed of
> light", but the standard fixes it to a constant.
> 
> I suspect that is what the graph you are suggesting will show, which is why
> I'd like to see it.
> 
> It's sad to look back at these old marketing  battles and see how the
> distortions of fact arose and stuck with us.
> 
Absolutely right. This was why I asked this question because I never got
a reasonable
explianation on some my experiments on the local ethernet. 
 
> Religion seems to work because it places much less burden on detailed
> thinking and analysis than does science.  Technical "religions" seem to
> work the same way.
hi, Reed, which one of your laws fitting in are you talking about?
I remember that you had made some laws on computer sciences-:)

Best
Dan
> 
> - David
> --------------------------------------------
> WWW Page: http://www.reed.com/dpr.html