Switch Reboots itself

entourage714 used Ask the Experts™
My Dell Managed powerconnect 2724 switch keeps rebooting randomly. It is connected to a managed powerconnect 5224 that does not reboot. checked all the cables and there are no loops. cant find any way to log whats going on with the switch.
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typically this is due to a bad power supply.


hmm moved the power to a different outlet. and changed the cables. then called dell and had it replaced with another switch. still rebooting.. arg...
Are you able to narrow down a particular connection on the switch - which, if removed - causes the switch to function normally?

If you disconnect it from the 5224, does the switch stay up for longer?

Do you by chance use jumbo frames on the 5524?

Do you have the latest firmware loaded?


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well i have started to narrow it down. i moved the device that was putting the most traffic through the switch to another switch. monitoring if will reboot.

the reboots are random so i wont know until i see it or until a user tells me.

cant disconnect the 5224. its a live network.

jumbo frames disabled.

yes all units have the latest firmware.

Sorry for all of the questions... :^)

Does the 5224 show anything in its logs for the port interconnecting to the 2724?

For the interconnecting port, is it set for auto speed & negotiation? I think it is safer to hard-set both sides to the same parameters. What about flow control?

Also, unless you have need for it, you could disable spanning tree. On the 5224: "no bridge 1 spanning-tree"

Are you trunking between switches, or are they on a simple switchport interconnect? Do you use link aggregation (multiple interconnect links bonded together, to improve performance and for fault-tolerance)?

What about different VLANs?

Also, here's a good one: please ensure that neither switch has port mirroring enabled for any port... I had a client once who decided to put a security device on a 48-port switch, and port-mirror ALL of the traffic to a single GbE port. Let's just say he could not figure out why the switch was choking at random intervals... :^)


ill go through your suggestions tomorrow.


Just FYI, All switchs reboots at the same time. I just didnt see it until I reset my 5224 and got on to the webinterface. i dont think its power because we have 2 sets of ups. my 2724 is plugged into a powerstrip thats connected to a separate ups then my 5224 and now 2708. But all three switchs reboot at the same time. My 5224 actually reboots and loses its static ip. Which was what was happening to my 2724 before i swapped it out.

Answers for NotLogic:
Yes there are some errors on my 5224 switch.
I have attached a pic.

The port connecting the two are on auto for both sides. Will hard set both sides to Gig.

Not too familar with spanning tree, and not sure how to disable it. under "spanning tree, bridge settings, spanning tree state" its set to enabled, should i disable that, any repercussions?

No trunk settings.

No Vlans.

No Port Mirroring.

thank you so much for your input.
Hello again...

Thank you for the information. It looks like your attachment might not have worked...

Spanning tree protocol (STP) is a mechanism which allows a network to protect itself against loops, and also to allow automatic failure mitigation. Please note that for the failure mitigation to work, the network topology has to be configured. "Out of the box" you get basic loop protection only.

So, is it safe to turn off? If you have a simple network which does not change often, OR you suspect that it is affecting something on your network, then "yes..." You can always re-enable it later. Please keep in mind that when you re-enable STP, it will cause an interruption in traffic of up to 30 seconds, while STP figures out how all of your switches are connected!

So far, it seems like you have a fairly standard LAN setup. I do not see anything obvious. Let's continue to dig further...

What is a little suspicious is that all of the switches reboot at the same time.

If you don't mind, could we investigate the power sources?

Are your UPSs managed - i.e. connected to some type of monitoring station? Does this monitoring station ask the UPSs to perform a periodic self-test? Are the UPS batteries in good shape? Can you go over there now, and unplug both without suffering a reboot? Some low-end UPSs used to suffer from slow transfer times (the time it took from them to go from AC to battery power). Certain equipment is more sensitive to that power disruption than others...

Do you have any other equipment connected to the UPS? A/C? Printer?

Again, thanks for taking the time to explain all of this. It paints a more complete picture....


Yeah it looks like at about 8:20am this morning it reboot again. and thats about the same time it did it yesterday.

I will turn off SPT tonight to see if it helps. How does spanning tree effect my teamed nics on both my servers. both servers have 2 nics that i bind into a team. and that are attached to the same switch the 5224.

Well the only thing i havent done is plug one of the switches on a different outlet that is not on the ups. but we have loads of things on that ups. switches, servers, and various other things.

Another thing i notices just now. i looked on my servers event viewer. this servers on the same ups and plugged into my 5224. event viewer sees the network when it comes back up at about 8-820 every morning. this may have been going on for quite some time now. now that i look at the event viewer. clients never complained. ill post the errors when i get on my laptop again. i cant get on the 5224 right now it rebooted and i cant find its ip.

thanks again!
Hi - just touching base to see how you're making out... I would love to get your issue fully resolved!




Thanks. it was the UPS.

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