Server Issues

[Gypsy]

2 machines:
PIII 800, 512 RAM - Dedicated server - static ip
P4 2.53, 512 RAM - Serve and play - another static ip
Both connected by Cable modem, cable rated at 3.2 down, 512 up
problem shows up with or without using a Linksys router.
Max ping set in config file set high (9000)

When serving each machine will run fine for a while, then without warning everyone's ping goes from 100-200 up to 15000 + and punts everyone from server.

Cable company says everything fine on their end (of course) and also advise that there are very few peeps on the cable node.

I have seen this in some other public servers where the pings will skyrocket and punt folks out, but the majority of the time I can play on the other servers without incident.

Could this be a cable modem problem or what? Its really getting to be a pain in the butt.

Thanks in advance for any help