1655MC dropping the network

[Matthew Schlosser]

I know these 1655MC's are pretty old, but for what I'm doing there should be
no problems.

Please excuse me if I am bringing up an old issue.  A quick search of the
archive didn't show me anything useful.

I have a dell 1655MC blade with the following:

Linux kernel 2.6.8
2GB RAM
PIII 1400MHz
Bind 9.2.4
Tg3 NIC driver from Broadcom, compiled and installed as a module
IP Tables disabled
Nic is 1000fdx to the switch in the blade chassis

The name server runs just fine at around 100-200 DNS queries per second.
When the load reaches 300-500 qps, the network will preiodically diappear.
I don't mean drop, I mean disappear.  It is very strange.  When it goes, the
following happens:

- No traffic is passed, TCP or UDP
- No errors occur
- Link status does not change, show up
- The OS thinks the user is still connected, even though the SSH traffic is
not passing (verified with KVM connection during an event)
- No errors on the interface
- No errors on the switch

The drop is for 30-60 seconds, then resumes.

Has anyone seen anything like this?

-Matt