Network drops out for a few seconds

[Shay2501]

I am running a mixed mode windows 2K network. This morning there were errors relating to the network being down when accessing network resources. The event viewer on three servers (all of which have 3Com 3C996B Gigabit Server NIC) have a tcpip eventid 4202 which states:
The system detected that network adapter 3Com 3C996B Gigabit Server NIC was disconnected from the network, and the adapter's network configuration has been released. If the network adapter was not disconnected, this may indicate that it has malfunctioned. Please contact your vendor for updated drivers.

Then x amount of seconds later, we get tcpip eventid 4201 which states:
The system detected that network adapter 3Com 3C996B Gigabit Server NIC was connected to the network, and has initiated normal operation over the network adapter.

These servers are connected to different switches and all of the windows servers have the same 3Com card, but not all are having this problem (just 3 are). This problem is also intermittent, for instance it started at 7:04 am happened about 4 times before 8:00 am; then started up again at 8:59 am. Any input would be great. Thanks in advance.

 

[bcastner]

You would hope for a 4201 event after a 4202.

Your first signs of impending switch failure would be my guess. (likely just one switch). If it was a logical network error you would have seen a different error source for the event than tcpip: e.g.

http://support.microsoft.com/kb/q174395/

 

[vipergg]

I would also check for other things like switch utlization when this happens , do you have a broadcast storm or some infected server eating all the bandwidth .