Intermittent Fault Through 3Com

[6Foot2]

We are seeing a problem here where one of our 3Com switches does not allow traffic through. Sometimes it does not even connect to the network at all. It is connected to the network from another switch which itself is connected to the network via cable. This second switch does not show any connectivity problems, as it serves the needs of a room full of 15 stations without too much bother.

 

I have connected the troublesome switch [sixth Form Study] via a module in the back, via the ports at the front and via a new module in the back. All to no avail. This fault is even more of a pain because it comes and goes unpredictably.

 

I have even connected Sixth Form Study with the only spare switch I have to hand, a Cisco Catalyst 2950 Series. This helped for a while and then succumbed to the same intermittent fault. I have checked both feeds from Sixth Form Study back to the fibre connected switch [LRC] and both pass.

 

Any ideas?

[Geoff]

Badly grounded?

[6Foot2]

Badly grounded?

 

I had thought of that too, but discounted it, as the feed from LRC to Sixth Form Study is via Foil Twisted Pair and I thought this should give a good grounding. Anyway, the same poor grounding fault on BOTH cables? Surely not?

 

Update: Sixth Form Study is now connected: No action from me to change the status since this morning!

[Geoff]

Clearly then, it was the pixies.

[6Foot2]

Clearly then, it was the pixies.

 

This is hardly a constructive or helpful reply. Do I take it from this that we have exhausted all of the possibilities? [Except for the unlikely one indicated above: Pixies]

[localzuk]

Is it a managed 3com switch? If so, have you tried updating the firmware?

[6Foot2]

Is it a managed 3com switch? If so, have you tried updating the firmware?

 

Yes it is a managed switch. I haven't got time to try this tonight, but first thing tomorrow....

 

By the way what are the risks? If the update goes wrong is there a chance that I could 'break' the switch completely?

[Ric_]

In my past job I had a room full of machines with Realtek onboard NICs which would occasionally decide not to communicate with a 3COM switch... to remedy this I had to reboot the switch.

 

Is it the endpoints that cannot communicate (as above) or the switch itself?

[6Foot2]

... to remedy this I had to reboot the switch.

 

Is it the endpoints that cannot communicate (as above) or the switch itself?

 

Both switches involved in this scenario have been rebooted many times and this does not remedy the situation.

 

The problem lies with switch-to-switch communication [LRC<->Sixth Form Study] When the problem is present, the switches are not talking....at all. It as if the one switch does not exist as far as the other is concerened.

[Geoff]

Clearly then, it was the pixies.

 

This is hardly a constructive or helpful reply. Do I take it from this that we have exhausted all of the possibilities? [Except for the unlikely one indicated above: Pixies]

 

The 3com kit I have here will randomly drop out and die if I don't remember to reboot them occasionally (looking over nagios/cacti it would appear to be about 40 days). This is a known 'issue' with older 3com kit (I have superstacks). Hence my dis-satisfaction with them.