We are running Windows Server 2003 and recently updated our old hubs to 3Con switches and old cat-5 cables to fiber and 3Com transceivers. In the last month we are experiencing intermittent (4 out of 5 days a week) downing of our server at about 8 am (we are a school system and it is approximately the time that most of our staff of 75 attempts to log on to our system). If we do nothing, the system will come up within an hour or so, and if we power off the 2816sfp plus switch it will come back up in about 15 minutes. We have replaced the switch and the problem persists. 3Com tech support suggests that we are having a problem with a Broadcast Domain and that when the traffic is heaviest first thing in the morning it is causing the switch to become "confused" and that after time it sorts itself out. We are at a loss as to how to resolve (or even to properly troubleshoot) this issue. Any help that you might provide would be greatly appreciated!