3Com Switches Resetting

OK Guys - nice easy one.

We got 3 Com switches around the school - approx 35 - 48 and 24 ports. Mainly 3200's series - main switch 4950. 8 or 9 cabinets all star linked via fibre. We now have 4200Gs in most cabs so as the switches are not stacked but connected individually to the 4950 via gig ports on 4200.

Problem is we are frequently getting switches randomly resetting around the school. This can be a power reboot - or the switch will not ping for a period of approx 30 seconds to a minute then returns to normal.

We have had this for a time. We have tried a number of things but still do not have the answer.

We know its not a loop. We have spanning tree enabled. Have ups and filters on some switches and cabs. The network traffic is not showing high - servers etc all on 1gb backbone. We have vlans (admin and curric) but configured ok. When a switch resets the workstations connected to it will give a bubble saying you are offline with an icon to restore connection. Pressing this synchs the connection and all is ok - though MS Publisher does not like it particularly!

2948 switches report frame discards occasionally but again nothing to show what the problem is. Utilisation very low usually.

We sometimes get the domain not available but have recently found that UPnP protocol in Windows may be causing problems. Removing this allows the workstation to see the domain as normal again.

Other issues such as pupils sticking chewing gum in network ports and partially disconnecting the network cable from the net socket will not be helping!

So if someone could tell me which button to press that will fix it all then that would be great ;-)

I am pretty sure that this is not a power problem. I have seen this behavior before on 3 com networks. on 99% of the cases it has to do with spanning tree. So i would start with that

bio..

We had similar problems a couple of yrs ago on our 3com network. Initially we thought it was power but it turned out to be a fault with an ancient hub that was crashing breaking the other switches that were plugged into it. As bio says, check stp.

HI

We had a problem with an old printers network cards and every time it started it bombarded the network with traffic and the switch it was connected to kept falling over. It was a case of trial and error to find it and it took ages.

What I did was change the switch that kept falling over for a newer one which stopped the port that was bombarding it. This stopped the printer working and that was the way I found it.

Just an idea.

Richard