I am setting up a small Beowulf cluster. I can run a number of the benchmarks indicating that it works: data is passed machine to machine, each machine will make calculations, all of the LAM examples work. There are two problems that keep coming up and any suggestions would be greatly appreciated. - at times there are delays in the network because a ping can take up to 1 sec to go to any one or all of the machines. The machines are all on 10/100 NICs with a 100 MB Hub. If the machines are carefully rebooted (meaning rebooting one at a time until it is all the way back up again) this problem will seemingly go away. So .. any time there is the ping delay, the rsh delays everything - which causes the cluster many problems. Any thoughts on rsh parameters that I should change or set differently? OR is there something running on the system that can cause these ping or rsh delays? - We have installed LAM and MPI related software. All of the LAM examples will start, run, and complete successfully. Many of the MPI examples will come back and tell me that the process did not close or finalize on some of the nodes properly. I apparently have some setup problem ... but as you can tell - I have no idea what. Any suggestions or recommendations would be greatly appreciated. I have posted in comp.parallel and comp.parallel.mpi on a couple occasions with no luck. All of these issues occur on a RH 7.2 installation - all systems (5) Thanks in advance! Randy