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We are using a switch (ZIO-SW500) connected to the building main network and we suffers from intermittent network halt.

Normally the network works well. But, sometimes traffic designated to other IPs floods in and our network halts for a while (1~3 minutes). Packets were captured by WireShark, and huge number of packets to certain IPs were observed. (the IPs are not connected to our switch) Mostly the packet belonged to TCP protocol and we think that the traffic itself is normal. It seems like that our switch randomly fails to block these packets.

Our network manager tried to help us but as the network break down takes place only 1~3 minutes and about 10 times a day, he cannot find the cause of the problem.

Currently we are considering changing the switch (though this switch is the one replacing the previous one due to the same problem.) under the hypothesis that our swtich had reached its maximum switch capacity and give up working.

Magellan
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Seungpyo Hong
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    From what I see, the ZIO-SW500 is a real crappy 100 MBit/s device. Get a decent quality Gigabit switch and be done with it. Other than that you have to identify the source of the stray packets and eliminate it but your description is too unclear to get anything out it to help you. – Sven Jun 25 '14 at 04:48

1 Answers1

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Over the years I've had 10 - 15 small 10/100 Ethernet switches "go crazy" and begin flooding out all ports w/ 100Mbps of "garbage" traffic. In at least 3 cases I was able to reproduce the effect by plugging-in my laptop computer (and nothing else) to the switch. (I say "at least 3" because I finally to the point that I was just throwing the switches in the garbage and not investigating them.)

In the instances that I've bothered to capture traffic I have seen legitimate frames being resent by the switch, over and over, typically with "garbage" creeping into the frame starting at the end of the frame and, over time, moving up into the payload.

I suspect this is a failure mode of some common 10/100 Ethernet silicon that all the switches I was using had in common.

I also suspect that this is what is happening to you.

Like the @SvW said in a comment: Buy a better Ethernet switch-- preferably gigabit, and if you care at all about troubleshooting, managed.

Evan Anderson
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