Tugger the SLUGger!SLUG Mailing List Archives

Re: [SLUG] Synchronous network ?


johna@xxxxxxxxxxxxxxxxxx wrote:
> 
> Present ethernets, from what I understand, transmit on demand and
> perform a random timeout in the event of collision. This means
> throughput drops at around 60-70% utilisation (can't remember the
> exact figure).

I thought it was 80%
> 
> How about having the nodes in a cycle, where each one transmits, after
> which the next one either transmits data or a "I'm here but no data
> to transmit", so the next one could.

It is called token ring.
> 
> This represents an overhead when there is no data, but for network
> intensive applications present over the whole network, it would mean
> that 95% - 100% network capacity could be used (assuming maxmimum
> 5% overhead), which is a lot more than, say 75% and it would mean
> the network performance would decline linearly at saturation rather
> than failing dramatically.

I believe token ring goes to 95% and doesn't go any higher or lower, but
I've never used it in practice.

As I undertstand it, IBM token ring goes to 16Mb, but they didn't do a
100Mb or higher version.

There may have also been problems with the plugs. I've tried ethernet
make and break plugs and they were a disaster.

--
   Terry Collins {:-)}}} Ph(02) 4627 2186 Fax(02) 4628 7861  
   email: terryc@xxxxxxxxxx  www: http://www.woa.com.au  
       or terryc@xxxxxxxxxx 
   WOA Computer Services <lan/wan, linux/unix, novell>
   snail:  PO Box 1047, Campbelltown, NSW 2560.

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