The IBM cluster currently consists of 22 IBM RS/6000 43P-260 workstations and 2 44P-270 workstations. Each 43P-260 workstation is configured as follows:
The 24 workstations are connected by an Fast Ethernet switch (using hostnames n0.fast.ameslab.gov through n23.fast.ameslab.gov). Nodes 1-23 are also connected by Gigabit Ethernet for high-speed communications using an Extreme Networks BlackDiamond 6808 Gigabit Ethernet switch. The switch is currently configured with 32 ports, upgradable to 64 ports. This provides a flat network for cluster communications fully supporting Jumbo Frames. Note: Extreme Networks offers a fixed form factor Gigabit Ethernet switch in configurations up to 32 ports, the Summit 7i. The Summit line offers considerable cost savings over the BlackDiamond line, but we are planning to expand the switch to 64 ports in the very near future and thus required the additional expandability of the BlackDiamond.
Prior to the installation of the BlackDiamond switch the cluster was connected via four 9 port Gigabit Ethernet switches from Alteon. The network for the cluster looks like:
This resulted in an 16 CPU (8 box) scalable unit: