Networking help

[Bumzilla]

Got a puzzling problem with networking at work.

I got a wireless linksys ADSL modem router and networking it to a 3com switch.
I don't know if I'm doing it right, but should I be connecting the router to a switch or hub and the router will assign dhcp to the pc's right?

Then another problem I have is the cabling. Somehow if my cabling is longer than 30m, the connection degrades. I thought the cabling will degrade after 100m?

THanks!

 

[LazyLion]

Got a puzzling problem with networking at work.

I got a wireless linksys ADSL modem router and networking it to a 3com switch.
I don't know if I'm doing it right, but should I be connecting the router to a switch or hub and the router will assign dhcp to the pc's right?

Then another problem I have is the cabling. Somehow if my cabling is longer than 30m, the connection degrades. I thought the cabling will degrade after 100m?

THanks!

Yes, that is how we all do it. Connect the router to the switch and all the PC's will be assigned their own address. (But you can of course also assign each PC's own internal IP).

Make sure that your cabling is not running parallel to any power lines or even security wiring. If it is, then try to shield the network cable.

 

[Bumzilla]

bump

 

[sn3rd]

Did you discover any parallel-running cabling? That could be causing the poor signal. If you find some, you could also try running your cabling orthoganally to the offending cables. This is not always possible, though. Try run a loose cable (just sitting on the floor or whatever) and see if it runs longer without significant attenuation. It could be the switch not supplying a strong enough signal (check this with a cable tester: just a bit expensive if you don't have one or know someone who has one), or it could be the cabling. Is it new cabling? What rating is the cabling? Are the jacks correctly crimped onto the cable? Try running a crossover from pc to pc over a longer distance than 30m (this can help you determine whether it is the switch or the NICs).

 

[Nerfherder]

Dont run UTP longer than 25m.... for 100m use fiber. Most places wont cut the cable longer than 25m.

If you want to run 30m then find a place in the middle to have a repeater.

 

[ghalied]

describe the degradation symptoms, poor speeds, packet drops etc

 

[sn3rd]

Dont run UTP longer than 25m.... for 100m use fiber. Most places wont cut the cable longer than 25m.

If you want to run 30m then find a place in the middle to have a repeater.

I've run very reliable 80m UTP plenty of times

 

[Bumzilla]

thanks for the replies.

I got a reel of cat5e cables. So this should be good stuff. I'm cutting them up and running them along the cable ducts. the length I've tested was from 15-30m and signal strength is really bad. I know the cables are crimped properly but will find a cable tester just in case. There shouldn't be any interferance but it could be the switch that is the problem. Will double check the switch.

 

[sn3rd]

Poorly crimped cables are going to give terrible signal quality. "A chain is only as strong as its weakeast link". Fix the crimps.

 

[Nerfherder]

I've run very reliable 80m UTP plenty of times

What hardware are you using ? A normal hub ?

 

[sn3rd]

What hardware are you using ? A normal hub ?

Switch... done it on 3Com, STLabs, SMC, Cisco and a few no-namers

 

[Nerfherder]

I didn't realise that a switch gave you that much of a boost....

Still 80m of UTP is doggy... are you using switches on both sides ?

 

[sn3rd]

Used both switch-to-switch connections and switch-to-pc connections. Longest reliable connection I've used was slightly more than 110m UTP Cat5e. I wasn't sure if it was going to work, nor how stable it would be, but it was ok. Wasn't a permanent connection ANYway.

It provides for better performance because the switch doesn't broadcast out on every port (which eats up available bandwidth). It can help to keep the traffic on the network nice and neat.

 

[ghalied]

sound like you need to enable STP or RSTP on those switches that have the feature as your network is possibly suffering packet loops in your , these packets will go round in circles and just hog the network.