This may not work on this area.
I have a SonicWall 1260 security device that has basically switch ports on it. ALLsix of my servers would disconnect from it at the same time for 1-2 seconds and then come right back up. SonicWall was no help. Watching the switch lights they would go out on the server ports at same time servers lost connections. (go figure right?) But not the AP unit or the WAN or the uplink to another switch.
Finally I set all the nics and ports to 100mb\full duplex. That fixed the problem on three servers. Three are still doing it. They are all the same Dell PowerEdge 2800s with Intel Pro 1000 MT nics.
Please any ideas would be great.