[Beowulf] Cluster Diagram of 500 PC

[Mark Hahn]

> Anyway, hop latency in Ethernet is most of times just peanuts in terms of
> latency compared to TCP/IP stack overhead...

unfortunately - I'm still puzzled why we haven't seen any open, widely-used,
LAN-tuned non-TCP implementation that reduces the latency.  it should be 
possible to do ~10 us vs ~40 for a typical MPI-over-Gb-TCP.

but my main motive for asking was to spread the _bandwidth_, since STP
creates BW hotspots that would be 4.8x over-subscribed in the simple 
and fairly flat topology I described...