simulate network cable unplugged

[Antoine]

Hello,

I am experiencing random network disconnection on my XP Pro box.

So far I could not find the reason for such disconnection, so I'm
trying to find the fastest way to recover it.

rebooting the machine brings back network connection, but is far too
much time consuming.

I tried enabling / disabling the network adapter, but that doesn't
change anything.

I finally realized that unplugging and re-plugging the network cable
was solving the problem in a few seconds...

I therefore have 2 questions:
- is there a way to "simulate" a network cable "unplug / replug"
action with a specific windows command / utility ?
- can I conclude that the root of the problem is at the network layer
2 level, and which steps should I follow to narrow down & solve it ?

thanks for your help

Antoine

 

[Ricky]

Try going to device manager..right click on your network card
entry..properties and make sure "Allow the computer to turn off this
device to save power is not checked".

 

[Kent W. England [MVP]]

Antoine wrote on 16-Sep-2004 7:50 PM:

I therefore have 2 questions:
- is there a way to "simulate" a network cable "unplug / replug"
action with a specific windows command / utility ?

Run "ipconfig /renew", if you are using dynamic addressing.

- can I conclude that the root of the problem is at the network layer
2 level, and which steps should I follow to narrow down & solve it ?

Yes. You could have a weak wireless signal or a problem with auto-detect
on your hub or switch. The connector could be flakey. Try replacing each
physical component one at a time to find the culprit.

Some types of network give this sort of signal when all other nodes are
off. Is this a home phoneline or powerline network?

 

[Antoine]

Run "ipconfig /renew", if you are using dynamic addressing.

hmmm, IP addresses are fixed, I'm not using DHCP, but I'll give that a
try anyway.

Yes. You could have a weak wireless signal or a problem with auto-detect
on your hub or switch. The connector could be flakey. Try replacing each
physical component one at a time to find the culprit.

Some types of network give this sort of signal when all other nodes are
off. Is this a home phoneline or powerline network?

it's a office network, with 3 different networks connected to one
Cisco L3 switch. there's no wireless, it's as simple as you can get.

the PC is connected to a 3Com switch, itself connected to the Cisco. I
tried connecting the PC directly to the Cisco, but we ran into the
same problem...

btw, I already unchecked the "allow the computer to turn this device
off" checkbox, but nothing changed...

one thing I'm thinking about: the cable length between the Cisco and
the switch or PC is around 70 meters, could that be part of the
problem ?

maybe I should try to "reset" the Cisco interface on which my PC is
connected next time...

Antoine

 

[Kent W. England [MVP]]

Antoine wrote on 17-Sep-2004 11:57 PM:

it's a office network, with 3 different networks connected to one
Cisco L3 switch. there's no wireless, it's as simple as you can get.

the PC is connected to a 3Com switch, itself connected to the Cisco. I
tried connecting the PC directly to the Cisco, but we ran into the
same problem...

btw, I already unchecked the "allow the computer to turn this device
off" checkbox, but nothing changed...

one thing I'm thinking about: the cable length between the Cisco and
the switch or PC is around 70 meters, could that be part of the
problem ?

Has this cable ever worked before? Did the installer string the wire
right on top of your fluorescent lighting and is your light fixture
buzzing loudly?

Try setting the PC and the switch port to 10 Mbps and see if that helps.
It appears to me that you have an intermittent connection, which could
be caused by interference, poor termination, damaged patch cord, etc.
Running at a slower speed could clear this up.

 

[Antoine]

Has this cable ever worked before? Did the installer string the wire
right on top of your fluorescent lighting and is your light fixture
buzzing loudly?

nothing of all that, the cabling is pretty clean under the flooring.

Try setting the PC and the switch port to 10 Mbps and see if that helps.
It appears to me that you have an intermittent connection, which could
be caused by interference, poor termination, damaged patch cord, etc.
Running at a slower speed could clear this up.

could be that, I will try this, although I'm in need of network speed...

thanks !

 

[Kent W. England [MVP]]

Antoine wrote on 19-Sep-2004 5:01 PM:

could be that, I will try this, although I'm in need of network
speed...

But if it works at a slower speed, you have eliminated all software
causes and can focus on finding the hardware that is the problem.