How should we implement the hardware and network ?

The nicest PC-Farm setup I found is Sarnoff Research Centre's Cyclone cluster www.sarnoff.com:8000/docs/metacomputing.html
Please look at the pictures. The configuration is:
128 dual processor nodes ( 64MB , 3.2GB disk, CDROM, 2 SMC 100Mbit ethernet cards , NO floppy drives, NO graphics cards )
Each node is connected to 2 3COM3c3000 36 port fast ethernet switches making a public ( for NFS .. ) and a private network ( for application trtaffic only ). The private network uplinks via fibre to a gigabit ethernet switch forming a "fat tree" network. 10 boot CDROMs enable complete reinstallation of all software in 80 minutes. FreeBSD is deployed in addition to Linux

Faster than 100Mbit ethernet is currently still expensive eg myrinet , gigabit ethernet, pVIC.

For the link to North Hall we need more bandwidth than the single FDDI link currently available.

Unfortuneately it looks like a gigabit ethernet uplink between bridges in North Hall and DESY computer centre is not on because of the large distance and the special cable which would have to be installed.

Perhaps we should consider replacing FDDI by Optical Fast Ethernet between h1l4ioX machines and a fast ethernet switch in computer centre. It has to be investigated and tested if the current FDDI cables can be used for this. Otherwise we may have to at least install a second FDDI ring North Hall - Computer centre and network hardware with both FDDI and Fast- or Gigabit ethernet ( also expensive )
-OR- we have to maintain current L4 system for event rejection and live with a single FDDI connection to computer centre ( but this partially destroys the mission of this project )
-OR- we have to find space for the whole installation in the North Hall and live with very limited bandwidth to computer centre
-OR- ?
...we should discuss these matters with computer centre soon.

Addendum: During the meeting Ralf reported that it is now clear that many fibres
are available which between Hall North and DESY computer centre which are
suitable for optical fast ethernet. The suggestion is to install CISCO fast ethernet
switchs on both end of these fibres ( say 3 or 4 links between the switches ) and
use the rest of the ports on the North Hall side to connect the h1l4ioX machines
on which we will replace the FDDI interfaces by fast ethernet.