|
|
|
|
| Author |
Message |
Pradeep
Guest
|
 Posted: Thu Oct 12, 2006 12:15 pm Post subject: Switch stops working after five minutes - any switch I try. |
 |
|
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 |
|
| Back to top |
|
 |
Fix your Windows Problems - FAST.
FREE Safe Scan Registry Check. Locate & Fix Errors in Minutes!
|
|
DLR
Guest
|
| Posted: Thu Oct 12, 2006 7:18 pm Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
Pradeep wrote:
| Quote: | 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?
|
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. |
|
| Back to top |
|
|
Pradeep
Guest
|
| Posted: Thu Oct 12, 2006 11:25 pm Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
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:
| Quote: | Pradeep wrote:
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?
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. |
|
|
| Back to top |
|
|
DLR
Guest
|
| Posted: Thu Oct 12, 2006 11:52 pm Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
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:
| Quote: | 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:
Pradeep wrote:
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?
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.
|
|
|
| Back to top |
|
|
w_tom
Guest
|
| Posted: Thu Oct 12, 2006 11:52 pm Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
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.
Connect a plug-in protector into wall receptacle attached to breaker
box. Then that power strip might have an earthing connection. Then
the power stirp might be doing something useful. But the 'whole house'
protector - being properly sized - is a superior solution.
Pradeep wrote:
| Quote: | 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. |
|
|
| Back to top |
|
|
|
|
bud--
Guest
|
| Posted: Fri Oct 13, 2006 11:49 am Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
On Oct 12, 5:24 pm, "w_tom" <w_t...@usa.net> wrote:
| Quote: | 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. .
|
The best information I have seen on surge protection is at
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
- 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
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
- 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.
| Quote: | 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.
The IEEE guide clearly describes protection as primarily clamping, not |
earthing.
bud-- |
|
| Back to top |
|
|
w_tom
Guest
|
| Posted: Sun Oct 15, 2006 10:22 am Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
bud-- wrote:
| Quote: | The best information I have seen on surge protection is at
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
- 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).
...
|
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:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
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):
| Quote: | In actual practice, lightning protection is achieve by the
process of interception of lightning produced surges,
diverting them to ground, and by altering their
associated wave shapes.
IEEE Green Book (IEEE 142) entitled 'Static and Lightning Protection |
Grounding':
| Quote: | Lightning cannot be prevented; it can only be intercepted or
diverted to a path which will, if well designed and constructed,
not result in damage.
|
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.
| Quote: | The IEEE guide clearly describes protection as primarily clamping, not
earthing.
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. |
|
| Back to top |
|
|
bud--
Guest
|
| Posted: Mon Oct 16, 2006 9:51 am Post subject: Re: Switch stops working after five minutes - any switch I t |
|
|
On Oct 15, 12:22 am, "w_tom" <w_t...@usa.net> wrote:
| Quote: |
Protectors that are UL protected created problems demonstrated by
scary pictures:
The usual horror pictures. |
| Quote: | http://www.hanford.gov/rl/?page=556&parent=554
For those who can read, the Hanford link specifically references the |
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.
| Quote: | http://www.zerosurge.com/HTML/movs.html
This link is for ZeroSurge, and is to push their plug-in suppressor |
technology using series mode protection, which you say doesn't work.
| Quote: |
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.
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.
| Quote: | IEEE does not make recommendation in Bud's papers.
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.
| Quote: | IEEE makes
recommendations in standards. Standard contradict what Bud claims:
IEEE Red Book (Std 141) ....
IEEE Green Book (IEEE 142) ....
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
| Quote: | 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.
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-- |
|
| Back to top |
|
|
|
|
| |
Watched Topics
Search
Register
Log in to check your private messages
Profile
Log in
Memberlist
Usergroups