Dlink Switches random locking up

We have 4 separate buildings all connected with 1gb fibre backbone. All the fibre switches ar DLINK DGS-1224T. Over the last 6-12 months these switches have locked up on several occasions. Not all at once but sometimes three of them will lock. We put the first incident down to some kid plug a network lead into two outlets.

But the locking up is happening far too often, my NM does not have a clue and he purchased these switches. I have read a little on them and seem to recall something about the tables becoming corrupt. We do nt manage these switches apart form giving them IP on our network.

Does anyone know what could be casing this?

1) Power problems. Put them on UPS.
2) Firmware bugs. Try flashing them if there's an update.
3) A network loop. Enable spanning tree protocol.
4) Overheating. Get Air Con.

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3) A network loop. Enable spanning tree protocol.

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Can you give me a bit more info on this please.

http://en.wikipedia.org/wiki/Spanning_tree_protocol

Should be an option in your switches configuration page somewhere to enable it.

I think I've heard sinething about this before somewhere and it was a firmware bug... I may be wrong mind... I often am ;)

The reliability of our network improved massively when we stuck them on UPS, most of our wierd network issues were a result of power blips.

(though around here you can't spend ten minutes in the server room without hearing the UPS' switch over at least twice due to rubbish power.)

@pete did you find the switches rebooted completely or did their 'uptime' stats say abything about the power blip? could you measure the power blip at all?

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Originally Posted by CyberNerd

@pete did you find the switches rebooted completely or did their 'uptime' stats say abything about the power blip? could you measure the power blip at all?

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Ironically enough we lost power from 11:30 -> 5:00 today on the phase that supplies my office. Anyway........

No, the switches would have enough power to keep going, but became flaky quickly after a power blip occurred (identified by lights dimming etc). The "dumb" switches suffered the worst and the managed switches didn't show a loss of power / uptime in the logs. All cleared up after rebooting the switch.

IIRC the logs for the server UPS' (APC kit can show a graph) show regular overvolting from 5-30v and undervolting up to 100 volts. I don't think I have the figures from particular days anymore.

I don't know enough about switches to guess why they went flaky - a corrupted cache of mac addresses would probably do it?

Now they have UPS' on them any connectivity problems are the result of unplugged network cables. We put a £50 desktop UPS in each cabinet (we have 14 cabinets).

The downside of a UPS in each cabinet is your cabinets (some in teaching rooms) will squawk when power goes down and cabinets may not come back online when power does if the UPS battery is drained (such as overnight power cut). The increased reliability is worth those minor niggles.

oh, btw - cheers for the icp-epia recommendation a while ago. Best price we found.

Thanks, I'm going to pay a bit more attention to the power-side of things in light of your post. We've had a rare but occasional network problem that I've never been able to nail - I had assumed the power was fine because the switches never restarted, now I know better :)

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Now they have UPS' on them any connectivity problems are the result of unplugged network cables. We put a £50 desktop UPS in each cabinet (we have 14 cabinets).

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any recommendations?

APC back-ups cs 500 for wall-mounted cabinets (up to 3 switches) - manufacturer # BK500EI. Gives about 30-45 mins battery life per cabinet, depending on the switches.

Main switch rack in the server room uses a 1000 model that used to supply the servers before we switched to 1500's. Powers 6 switches and a rack holding 6 fibre converters. I don't think they make them any more - equivalent would be #BR1000I @ £150-ish.

I chose APC because I've always used them - I didn't look at any other kit.

hint: improving network reliability = use of development funding.
hint2: most multiple-plug adaptors and rack-mount pdcs can be butchered to take a UPS-compatible kettle lead

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Originally Posted by pete

hint2: most multiple-plug adaptors and rack-mount pdcs can be butchered to take a UPS-compatible kettle lead

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I like the APC kit its good stuff, but have also used MGE and Liebert stuff recently which is also good stuff. For your cabinets, extensions etc, why not just get a re-wireable plug from CPC / RS, they are like 75p, chop off the normal one and wire that one and bossman's your uncle.

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Originally Posted by john

why not just get a re-wireable plug from CPC / RS, they are like 75p, chop off the normal one and wire that one and bossman's your uncle.

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Unless you are NICEIC registered, you probably aren't allowed to do this are you?

I think you can get away with it if you are classed as compitant, so that means teachers must not try but us techies are fine :D Seriously, check if you have rules against it, but as your not modifying ring mains etc, its just like replacing a broken plug which you can do, so I suspect that you are fine doing that job.

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Originally Posted by john

why not just get a re-wireable plug from CPC / RS, they are like 75p, chop off the normal one and wire that one and bossman's your uncle.

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me? er, because I have 3-4 boxes of ups kettle leads that I won't otherwise find a use for. :)