Strange network problems -- please help.

[skarydrunkguy]

I have installed a wired network in my house, and I am having problems with 1 of the remote ports. The port in question is approximately 75 feet away from the router. The problem that I am having is that the computer, when set to autosense the network, will connect at 100MBps for about 1 second, then disconnect for about 10-15 seconds, then connect again in an infinite loop. When I force the connection to use 100MBps, it can't connect at all. If I force it to 10MBps, it doesn't connect at all. If I use my laptop (instead of the desktop which will be the eventual recipient of the connection) to test the port, it can connect reliably at 10MBps only, with the same problems as the desktop otherwise (the connect/disconnect loop). After some research, I found that I am well within the 100 meter limit of cat5 cable, and I have no more than .5 inches of cable stripped at both ends for the wall plate connections (RJ45 Keystone connectors) have made sure that the cable is not kinked, and have even run continuity tests on all the leads for the wall cables and both patch cables. I cannot figure out what on Earth could be wrong! Any ideas would be appreciated.

All of the other 8 remote ports work fine, though none are quite as far away. My guess is that it's a cable issue of some sort (what sort I know not) but since I cannot re-run the cable, I hope its not.

 

[prometheusxls]

Check your setting in the IP properties and router properties. Try the PC in a differnt drop jsut to make sure it really works.

Check if the cable is good (use a line tester). It sounds like you did already.

Make sure your not plugged into the uplink. Try a different port on the router. Maybe the ports bad.

Try the PCs with another NIC. Check all coneections again, and again. If that doesn't work check for other environmental things that could be causing the problem with the line E.G. large motor or other EM interferance. Etc... Cat5 Cable running parallel to power / electricity cables. etc... If no other options, try to redrop a new cable. Its probabbly bad in the wall some how.

In the future run double drops, (twice as man as you need) this will keep you from these sorts of problems if the cable is bad.

 

[skarydrunkguy]

Thanks for the reply. I don't have a line tester, but I used a volt/ohm meter to test resistance on each pin of the wire, and they were fine. I'm not plugged into the uplink, and I've tried different ports on the router... I'm sure the IPs and such are fine as well. Is it possible that the laptop NIC has more power (and hence a stronger signal) than the PC's NIC? I wouldn't think so, but who knows? As far as I can tell, there's no paralell power lines or motors that would cause interference, though it does run paralell to heating ducts for about 10 feet... I wouldn't think that that would cause interference though. Unfortunately I can't run another line to that particular location due to construction and the fact that its been sealed off (well, without tearing down a wall or 2 anyway). Running double drops is a good idea, cat5 is cheap, where were you 4 months ago?

I was just hoping that someone else had a similar problem and that perhaps they could enlighten me as to an archaic 'rule' of networking that I don't know. Thanks again.

 

[PotatoMAN]

sounds kinda like a problem I had when I 1st started making cat-5 for myself. I thought that since it was straight-though cable that it didn't matter what the color cables were in the 8-wire heads, just so long as the cable color order from left to right of the 8 wires were the same on both ends. For the most part, it worked, but I got weird net problems like the one you are describing. Make sure your line follows the cat-5 standard (if there is one?) but I think it is something like striped orange, orange, striped green, blue, striped blue, green, striped brown, brown on both ends. If the wire is fine, and you tested it, your switch may not be powerful enough to send a good signal that long and to all the other ports, so try getting another switch just for that port if you can or unhook all the others and see what happens.

*EDIT: I thought it was 75 meters of cable you had for some reason... hmm... 75 feet shouldn't be a problem!

 

[prometheusxls]

Yea Potato is right about the pins and how they have to be setup. Use the B standard if its listed on your Keystone jacks / patch pannels. And all your patch cables should follow the same spec that Potatoe listed above. Only the B standard is compatable with 100TX connnections. I think it has to do with how the lines are wraped in the wire. HTH.

Replaicng the cable should be easy if you already have the drop installed. Since you already have the cable in the wall just attach the new cable to then end with a good ammount of tape and a cable tie or 3 and then pull from the other end.

 

[skarydrunkguy]

Interesting. I'll change the order of the wire connections and see if it makes any difference once I get home... I had considered putting a switch to act as a repeater about half way down the line, but ideally, it should work as is. There's always wireless if I absolutely have to, too.

I wish I could just pull another wire, but the way its run (down and over, up and over, down and through studs and stuff) and considering the length, you could probably yank as hard as you want and the cable would break before it moved. I don't recall, but it may actually be stapled to a few studs too.

Thanks for all your help, guys... all I could get from Dlink and SMC tech support was, "Turn off your firewalls, its clearly a firewall issue." Hah!

 

[ktwebb]

Take the PC and move it closer to the switch, using a differnt cat5 run. If it doesn't have problems then it's the cable. If you ran your own cat5 run then that is definitely the first thing to eliminate. Cheap cable testers can't really tell you if your copper is to spec. Sounds like it is not which is typical of homemade cat5 runs. Other things to look at if you can eliminate that but that would be my first inclination.

 

[spidey07]

yeah, it doesn sound like a split-pair problem.

Just make sure to follow the 568b patter on the jacks at both ends and you should be all set.