Switch stops working after five minutes - any switch I try. Please help.

Hello Netters,

I hope someone can help me. It has been a long day (and night) and I cannot think of anything else I can do to fix our network problem.

In our small business setup, a DSL modem is connected to a Linksys router. The linksys router is connected to a 16-port Linksys switch. Some ports are used direcly by some computers. Other ports are connected to some other 5-port switches (through a patch panel).

Although we don't have UPS anywhere, we have surge protectors for all of our electrical connections.

It all started this afternoon. Looks like there was some kind of electrical surge. Some of our computers just rebooted themselves.

After a couple of hours we started seeing this problem. Our 16-port switch just stops communicating. We cannot even ping machines on the neighboring ports.

If I unplug the power cable on the switch and plug it back again, things work okay for a couple of minutes. After that, once again the switch stops communicating.

Suspecting that the 16-port switch has a problem, we replaced the switch with a newly purchased 16-port switch. However, the problem seems to be still there.

Can someone please suggest us what the problem could be?

One theory I have is that some device that is connected to the switch (either the network card on the computers or one of the 5-port switches have started sending some wrong signals to the main switch, thereby messing it up. Is this possible? If so, is there a quick way to identify the culprit?

Thank you in advance for your help. Our network will be up for another couple of minutes, giving me a chance to post this message.

Regards, Pradeep

Reply to
Pradeep
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Start segregating your network. Unplug about 1/2 the ports on your "central" switch. If things stay up with this start adding things. If not remove 1/2 of this and try again. As long as things stay up for a while, add a few more things and wait a while. Repeat.

Or start buying managed switches so you can "see" who's acting up.

Reply to
DLR

Hi DLR,

Thank you for your help. It was a very long night for me.

I finally located the problem to two CISCO VOIP phones. Once I plug them in, the system goes down after a few minutes.

Is there any line conditioner that we can purchase? Don't want to throw the phones out.

Thanks Pradeep

DLR wrote:

Reply to
Pradeep

I'll bet that one or more of your Cisco VOIP phones has a blown ENet port. Or a very sick one. And it spewing out something that's killing your network. It may only be one. Try putting them back one at a time.

But stuff like this, if blown, are usually ready for the trash bin.

For the future you need to look at your office grounding. Let's talk when you're awake.

Pradeep wrote:

Reply to
DLR

You have demonstrated a protector does not stop or block surges and can even contribute to damage of the adjacent appliance. It is a shunt mode device. It does not 'power condition'. It simply connects a surge from one wire to all others. If that other wire is earth ground, then a surge is harmlessly earthed. But if that protector does not have a short connection to earth, then a surge is simply shunted onto all other wires and therefore into adjacent electronics. Your own experience implies same.

Effective protector is defined by its earthing. A 'whole house' protector on AC mains, if connected 'less than 10 feet' to earth, means surge would not find that VoIP phone. Effective 'whole house' protectors are manufactured with responsible names - Square D, Cutler-Hammer, Leviton, Intermatic, Siemens, and GE. They are sold in Lowes, Home Depot and electrical supply houses. Effective protectors have a dedicated earthing wire. Household earthing must be upgraded to meet and exceed post-1990 National Electrical Code requirements. Even the telco provided (free) 'whole house' protector also must make a 'less than 10 foot' connection to a common earthing electrode.

Why does the telco install this 'whole house' protector for free? Because it is so effective and so inexpensive. Same applies to your AC electric 'whole house' protector. Effective protection is earth ground. A protector is effective when it makes a 'less than 10 foot connection' to earth. Does proper earthing exist on your plug-in protectors? If not, then effective protection also does not exist. No earth ground means no effective protection. Even worse, a plug-in protector can contribute to damage of an adjacent appliance.

C> Thank you for your help. It was a very long night for me.

Reply to
w_tom

The best information I have seen on surge protection is at

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the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits" published by the IEEE in 2005 (theIEEE is the dominant organization of electrical and electronic engineers in the US).

A second guide is

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this is the "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home" published by the National Institute of Standards and Technology (the US government agency formerly called the National Bureau of Standards) in 2001

Both guides were intended for wide distribution to the general public to explain surges and how to protect against them. The IEEE guide was targeted at people who have some (not much) technical background.

Both say plug-in surge suppressors are effective.

Plug-in surge suppressors, as described clearly in the IEEE guide, work primarily by clamping the voltages on all wires to the common ground at the surge suppressor. They are not primarily shunt mode.

Interconnected devices, like a computer and printer, need to connect to the same surge protector. If a device, like a computer, has external connections like phone or LAN, all those wires have to run through the surge suppressor for protection. This type of suppressor is called a surge reference equalizer (SRE) by the IEEE (also described by the NIST). The idea is that the voltage on the signal wires, in addition to the power wires, is clamped to the common ground at the SRE. The voltage on the wires passing through the SRE are held to a voltage safe to the connected device. Using SREs may or may not be easy for your setup. If using a surge suppressor in a panel be careful to get a single point ground at the panel for the signal wires.

The IEEE guide clearly describes protection as primarily clamping, not earthing.

bud--

Reply to
bud--

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- the title is "How to protect your house and its contents from

This is his standard 'cut and paste' post. Meanwhile his recommendation is really a warning about how plug-in protectors can even contribute to damage.

Protectors that are UL protected created problems demonstrated by scary pictures:

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Plug-in protector fire problem was so serious 20+ years ago that UL created standards for backup protection. Undersized protectors - completely dependent only on backup safety protection - can still fail. See those scary pictures.

Just another reason why effective protectors are located at the service entrance, are sufficiently sized, and have that all so essential earthing connection.

Meanwhile, the lurker is invited to look at Figure 8 in Bud's citation. TVs are damaged due to a plug-in protector and defective earthing. Bud's IEEE paper warns about how plug-in protectors can even contribute to adjacent TV damage. TVs at 8000+ volts are damaged. Plug-in protector in figure 8 (even with UL approval and without earthing) contributes to TV damage. Just another reason why protectors are best located at the service entrance.

IEEE does not make recommendation in Bud's papers. IEEE makes recommendations in standards. Standard contradict what Bud claims: IEEE Red Book (Std 141):

IEEE Green Book (IEEE 142) entitled 'Static and Lightning Protection Grounding':

No earth ground means no effective protection. Even an open switch will not stop or block such surges. In direct contradiction to what Bud posts - IEEE recommends the most critical component in any protection system - earth ground. What can make that earthing connection? A 'whole house' protector - a solution that costs tens of times less money.

Effective solutions are sold in Lowes, Home Depot, and electrical supply houses. Effective protectors have never been seen in Radio Shack, Kmart, Circuit City, Sears, Staples, Best Buy, or the grocery store.

So why do Bud's own citations show clamping to earth? No earth ground means no effective protection. But then that is what the IEEE also recommends in IEEE Standards - the Red Book and the Green Book.

Reply to
w_tom

The usual horror pictures.

new UL standard with thermal disconnect as a fix for overheating MOVs.

plug-in suppressors

None of these links say the damaged suppressor had a UL label. None of them say plug-in suppressors are not effective or that they should not be used or that there is a problem under the current UL standard.

technology using series mode protection, which you say doesn't work.

For those who can read, Fig 8 is part of the IEEE explanation of how SREs work. For those who can read, the IEEE guide recognizes plug-in surge suppressors as effective.

To take only one example: the IEEE guide, chapter 6, "SPECIFIC PROTECTION EXAMPLES" shows 2 examples of surge protection. Both use SREs. Saying the guides take a lot of space describing, but not recommending plug-in surge protectors is sutpid. Repeatedly making this claim requires willful stupidity.

And you have to be stupid to think the IEEE would publish a guide to the general public that is not consistent with the IEEE color books. Maybe if you tried real hard you could understand the IEEE and NIST guides

Your religious views about earthing are nott relevant. As described numerous times, the IEEE guide clearly describes plug-in suppressors as CLAMPING the voltage on all wires to the common ground at the protector. Earthing is described as secondary. As you seem to forget, the IEEE guide was published by the IEEE.

The IEEE and NIST guides clearly say that plug-in suppressors are effective. Links to sites that say plug-in suppressors are effective: 2 Your links to sites that say plug-in suppressors are not effective: 0

bud--

Reply to
bud--

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