Network problem in connection to a 70m away pc

[starangel]

I have a network at home with an 6-ports switch and the computers are working ok. I have a pc which is 70 m away and when I connect it to the network the lights on the switch start blinking and on the pc I can see the connection switching between 10 and 100 Mbps. As if it can not make up its mind. So helping it, I have configured the network card to work on 10 Mbps Full system. This has made a connection. But still the connection is very slow and I can not use the internet which is shared on my server.
Now th weird part, is that when I take my laptop to that location and connect it, it works fine (of course after I configure the card to work on 10 Mbps full system).
Please let me know what could be the problem. I am right now assuming that the network card in the laptop is better than the network card in the pc since it is probably built in. hmmm... I am really lost. Please advice. Thank u.

 

[starangel]

I have found something funny in the wires. There is one which whenever I connect to the plug, the connection gets bad. I think this wire might be discontinuied somewhere. This could be the reason why I can connect on 10MBps and why it goes bezerk when I turn it back to automatic.
Could it be something else?

 

[bcastner]

1. It could be CAT-3 instead of CAT-5 cable.
2. It could be end connection equipment rated only CAT-3, like the wallplate;
3. The line can run through electricly noisy areas;
4. It can be an autonegotiation logical failure between NIC and router/switch

 

[starangel]

Thank you bcastner for your reply. I have checked the cable it is a CAT-5 cable. I have replaced the plug and still having the same. I am running the connection now at 10 Mbps. I think the cable is bad somewhere. Does this happen a lot? I am getting another cable and will replace it soon. I will also try to check the wires, two by two; since the ends are far away from each other.
I will keep you updated with what happens ith me. but thanks a lot.
Starangel

 

[starangel]

Bcastner,

I have changed the cables and still have the same problem.

Can u explain more on the number 4 reason u gave me, the autonegotiation logical failuer? Would this happen if I changed the computer and the wire?

How could I know what is the exact reason. I have checked the cable and it is 100% ok.

Please let me know how I could figure out the reason behind the 10/100 flickering.

Thank u.
Starangel

 

[TimRegester]

This sounds like an autonegotiation failure between the PC network card (or onboard Fast Ethernet port) and the 6 port switch.

There are standards for this but in cheaper switches and network cards the implementation of this can leave an awful lot to be desired.

The usual fix is to hard set both ends of the connection to a connection speed that both ends are happy with. In most cases the speed to aim for is 100BASE-T Full Duplex. So if you can change the PC nic speed to 100BASE-T Full Duplex with no flow control. If the switch is managed do the same that end if not see if you get a reliable Fast Ethernet connection with that setting.

If so job done, if not repeat with 100BASE-T Half duplex then 10BASE-T full duplex and finally 10BASE-T half duplex.

If you can only get 10BASE-T would say borrow and try a new switch (from a different manufactrer) if you can, if this does not fix it you may need to try a different network card in the PC.

 

[bcastner]

TimRegester above explained my earlier point #4 much better than I could.

One other possibility is a ARP broadcast storm. Make absolutely certain that the PC is not duplicating the IP used by another machine.

 

[starangel]

Thank you TimRegester and bcastner for your help.
I will try to borrow another switch and try it to see what happens.
Your help has been very useful.