icmp packet drops

[Hai Nguyen_1]

Hi folks,

I have two NT 4.0 boxes running OmniBack II clients and an HP 11.00 box running OmniBack II
server. They are on the same LAN and communicate through a switch. Their network interface cards operate at 100 Mbps full duplex. The switch' ports handle 100Mbps/full duplex as well. When there is no backup going on, there will be NO packet loss among the three hosts mentioned above. But as soon as a backup starts, the icmp packet drops among them will vary between 10% and 15%. And this packet loss rate is consistent. I suspect that the problem lies in the switch.
What can I do to exactly identify the root cause of the packet drop? Thanks.

Hai