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Network speed

Posted on 2000-02-22
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Last Modified: 2013-12-28
Like filmbuff in the Q&A, I installed a Win98 peer to peer network with a hub that was supposed to switch automagically recognizing both 10 and 100 Mbps.  I connected two new machines with fast ethernet to two older pentiums with 10Mbps ethernet.  The older machines used coax and a combo card.  I switched everything to the new and improved RJ45.  I upgraded the old machines from Win95 to Win98. The machines could see themselves in network neighborhood, but not each other.  I checked everything, cable, device and protocol.  Finally, I went to the store and bought a slower $20.00 hub.  The network operates but is very very very slow, slower than the Win95 network on coax. It proves however, that the cables and identifications are set correctly.  Why is the network so slow?
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Question by:Sherm
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MnNCOMM earned 100 total points
ID: 2548999
Sherm,

Many things can effect a networks performance.

Different cards in different machines that are not compatible with each other or don't work well with eachother, the wrong or outdated drivers for the network cards, improper coax/cable or coax/cable that is bunched up or routed along items in your enviorment that are causing interferrance, improper crimping of the proper transmit & receive pairs. Or just a slow machine.

I am not there, so I can only guess and tell you what to make sure is correct, before we try to determine whats wrong.

First off:

90 degree adapters, barrel connectors, extension cables and any other device you break the cable with will cause loss, and make it easy for any interferrance to get into your cabling.

Make sure the transmit & receive pairs are correctly crimped. If you notice in the cable you have FOUR pairs of wire. But the network only uses TWO pairs. One pair for transmit, the other to receive. A common misconception to people crimping their own lines is that they just make sure the pins line up on both sides. This is only PARTIALY true. You have to make sure that one twisted pair is TX and yet another twisted pair is RX. In other words Pins 1&2 (TX) use one pair, and pins 3&6 (RX) use another pair.

Use this color code and see if it helps

Pin 1 TX+        white w/orange
Pin 2 TX-            orange
pin 3 RX+        white w/green
Pin 4 (Not Used)      blue
Pin 5 (Not Used)  white w/blue
Pin 6 RX-             green
Pin 7 (Not Used)  white w/brown
Pin 8 (Not Used)      brown

See what I mean? The orange pair is TX, and the green pair is RX. I have seen many of slow problems as well as "sometimes I see them, and sometimes I don't" problems fixed by this.


Now assuming the cards are installed correctly, and there are no device conflicts or IRQ problems, you can also try using the manufacturers software to adjust the card. Try playing with the settings of Auto sensing, locking into 10MBPS, try locking it into 100MBPS.....

and so on......

If all else fails, call the manufacturer and ask them for help making sure it is installed correctly. If you bought something of a "Name Brand" product, you get tech support that is available without having to track some company named "Bob's Network Cards" that are manufactured in Malaisia or some other place off the map with no phone <smile>.

Hope it works for you, leme know how it comes out.

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by:Sherm
ID: 2549882
I did build and crimp the cables myself, but they are straight through cables, RJ45, and less than 50 feet long and not tangled.  The twisted pair are in line orange, orange/white, green, green/white, brown, brown/white, blue, blue/white on either end with the connector orientated in the same position one end or the other.  The network is working, but slow.  I am replacing two cards today--assuming it is the old cards for which I have no installation software.  The hubs I am working with are Linksys and Network the World by Linksys.  The only support at their sites are the instructions that came in the box.
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by:MnNCOMM
ID: 2551482
the cables will be straight through cables, (Meaning that the pins will be the same at both ends) But you have to make sure you use the right pairs. in the CAT cable you have 4 twisted pairs. You cannot break up the pairs, or use one conductor from one pair and another from another. Please re-read what I wrote prior.
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Author Comment

by:Sherm
ID: 2552878
I read and re-read your suggestion.  I still don't understand what difference it makes the color of the insulation on the wire--as long as pins three and six at the hub are the same wires as pins three and six at the ethernet card through the cable.  However, I did use your first initiative.  I was using all three protocols NetBEUI, TCP/IP, and IPX/SPX on all the machines just to be sure.  That was wrong because the machines were not all using the same protocol and so they must have to encrypt and decrypt (I'm guessing).  In anycase I eliminated them one at a time, rebooting three times or more.  I lost the net once, restored the protocol and eliminated the next, settling on IPX/SPX.  All's well.  Thank you.
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by:MnNCOMM
ID: 2552988
It is NOT only the fact that the pins line up at both ends, and it does NOT matter what colors you use for the pins. It ONLY MATTERS that you use one pair for TX and One pair for RX. These two pairs must be of the same twist.

If you notice when you strip the insulation of the wire, that there are FOUR PAIRS of wires. Each PAIR is twisted together. This twist helps keep the signal in the PAIR as well as sheild away any RF loss out of the cable, as well as prevent RF from entering the cable.

You can use any color you want, you can use any PAIR you want,but you have to make sure that ONE PAIR is used for TX, and ONE PAIR is used for RX. If you just simply wire it any old way, and just make sure that the pins line up on both ends, you will have TX in one pair and one leg of one pair for RX+, and yet another wire of another pair for RX-. Now you are "Outside of a pair" Thats why I gave you a color scheme, it shows how 1&2 are one pair, and 3&6 are another pair.

There is a reason why the wires are twisted, and there is a reason why they are four easy to identify pairs of wire within the cable.

Another example would be using it for phone wire. If you had 2 or 3 lines in your home, chances are if you use one multi conductor wire wrapped in the same sheild (or wire) you would have bleed over from all the other lines. "Thats what the twisted pairs do" You would use one pair for one line, another for another and so on. The twists work as a sheild to insulate each path or line.

This may not be your problem, but it is SURELY the most common problem of people that are new to networking. Sometimes the computers will be there, sometimes not, sometimes slow, sometimes not there at all except for everyother reboot.Check the wire first, then check the protacols, then check the settings of the cards. If your connecting but it is just slow, I tend to think it is not a protacol issue and more of a cable of network card setting that is doing it to you.

Cordless phones by a puter have been know to cause problems, Subwoofers from your sound card have been yet another problem for some networks.

Let me know how it works out for you, and please tell me you now understand about the PAIRS in the wire, and your not just making sure each pin lines up at both ends......
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