Cat5 Wiring Experts! Help needed! Please!

[Crimson]

I went over to a friends house today to run some wire for 100mb ethernet... We put the cable modem in a central location in the basement, then ran lengths of cat5e to 3 different rooms. Longest run was about 50 feet, shortest run about 20 feet. For some reason, I can only get these connections working at 10mb/half duplex.. if I set it to anything else, the computer recognizes the speed, but never sees the cable router.

Anyone got any ideas what I did wrong? I wired all cables from the router as 1-8 1-8 (Straight through), and crimped them. Is this not correct? If I plug in using a pre-made cable directly into the router downstairs, everything works fine at 100/full. Just the cables I made will not work. The cable I used was AT&T gigabit cable (Cat5e rated), and standard 8 pin rj-45 plugs.

Any ideas here?

 

[ChefJoe]

1-8? As long as you keep both ends with the same wire layout (if you put them side by side, the connectors look exactly the same) and did the crossover in the middle (typically it's exchange blue stripe for green stripe) that should do it.

http://www.cabletron.com/support/techtips/tk0231-9.html has a pic of your standard connector, Connector side up. cabletron

If memory serves, you may need a crossover cable for your cable modem to cable/dsl router (I assume that's the type of router you have). We are talking about a router right? Hubs cannot do 100 Full duplex usu.

 

[Crimson]

Thanks for the input.. I think I may have found my problem.. According to Intel's page (Among others, but Intel pointed it out SPECIFICALLY).. Pins 1-2 need to be of the same color/pair and pins 3-6 need to be of the same color/pair.. I wasn't doing that.. I was just doing straight through 1-8, not paying attention to the pairs.. so what I need to do I think is wire pins 1,2,3,6 using 2 different colored pairs.. instead of the way I was doing it.

 

[ChefJoe]

Crimson, print out the link I provided and get used to doing it that way. That's the industry standard color layout and it's just good to do it so other people don't mess with your work later. Both ends will look the same.

 

[joshInAlaska]

There are two Cat5 wiring standards for four twisted pairs. Both sides have to be the same.

Both standards are listed below:

A. GW, G, OW, Bl, BlW, O, BrW, Br

B. OW, O, GW, Bl, BlW, G, BrW, Br

For cross-over, you need to wire pins 1-3, and 2-6.

 

[Ark]

Your problem is definately in mixed twisted pairs.
It will work on 10MB, but will not on 100.
Pairs: 1-2, 3-6, 4- 5, 7-8

Like mentioned above where are 2 different standards on color codes to keep it common.

We had this problem many years ago, when we switched from 10 to 100 and suddenly only factory made cables were working

 

[Coherence]

Also be aware that the problem may not only be with your wiring, but also the fact that you are using cablemodem service. Cable is inherently half-duplex (at least in my area; it's possible full-duplex cable will appear here eventually, assuming it exists). You can't send and receive packets at the same time on cable. This is generally transparent to the average user, though. For example, if you are downloading a file while surfing, the download is interrupted for a split second when your computer uploads the packet requesting a new webpage, then the download continues where it left off.

DSL, on the other hand, is full-duplex. You can send and receive packets simultaneously. (Which is why many online gamers prefer DSL to cable; it's slightly better in real-time, even though cable sometimes offers faster downloads.)

 

[odog]

more fud....

the issue your hitting is most likely due to you not following the 568a/b wiring model. the crosstalk and NEXT/FEXT when using a non standard wiring pattern can reek havok on the faster speeds of ethernet.

Also be aware that the problem may not only be with your wiring, but also the fact that you are using cablemodem service. Cable is inherently half-duplex (at least in my area; it's possible full-duplex cable will appear here eventually, assuming it exists). You can't send and receive packets at the same time on cable. This is generally transparent to the average user, though. For example, if you are downloading a file while surfing, the download is interrupted for a split second when your computer uploads the packet requesting a new webpage, then the download continues where it left off.

DSL, on the other hand, is full-duplex. You can send and receive packets simultaneously. (Which is why many online gamers prefer DSL to cable; it's slightly better in real-time, even though cable sometimes offers faster downloads.)

all wrong... many modems only have 10base half duplex ethernet ports. newer modems have full duplex 100base connections. this is irrelavent anyway as he is tapping into a broadband router which has a 100base full duplex switch inside it. cable modems are 100% full duplex on the "cable" side on the modem. the delay your seeing is due to the TCP/IP overhead. all the TCP acks you send eat your upload(which is capped) and that hurts your down load.. the same thing happens on a standard ethernet network... start a large file download and then start to upload something... you'll see the performance of both of the sessions take a hit due to each others TCP acks.

 

[Coherence]

Originally posted by: e-phex
more fud....

the issue your hitting is most likely due to you not following the 568a/b wiring model. the crosstalk and NEXT/FEXT when using a non standard wiring pattern can reek havok on the faster speeds of ethernet.

Also be aware that the problem may not only be with your wiring, but also the fact that you are using cablemodem service. Cable is inherently half-duplex (at least in my area; it's possible full-duplex cable will appear here eventually, assuming it exists). You can't send and receive packets at the same time on cable. This is generally transparent to the average user, though. For example, if you are downloading a file while surfing, the download is interrupted for a split second when your computer uploads the packet requesting a new webpage, then the download continues where it left off.

DSL, on the other hand, is full-duplex. You can send and receive packets simultaneously. (Which is why many online gamers prefer DSL to cable; it's slightly better in real-time, even though cable sometimes offers faster downloads.)

all wrong... many modems only have 10base half duplex ethernet ports. newer modems have full duplex 100base connections. this is irrelavent anyway as he is tapping into a broadband router which has a 100base full duplex switch inside it. cable modems are 100% full duplex on the "cable" side on the modem. the delay your seeing is due to the TCP/IP overhead. all the TCP acks you send eat your upload(which is capped) and that hurts your down load.. the same thing happens on a standard ethernet network... start a large file download and then start to upload something... you'll see the performance of both of the sessions take a hit due to each others TCP acks.

All correct, actually. I work for the local phone company here, and my roommate works for the local cable company. I've confirmed these facts with my people and with my roommate. My DSL engineers confirmed that DSL is full-duplex, and my engineers and my roommate both told me the cablemodem service is half-duplex.

I did include a disclaimer in my original message, however, that full-duplex cable COULD arrive eventually. If it has, (which I can confirm with my roommate at Cox,) then you can certainly ignore my original statements.

(P.S. To the original post: Please forgive me if I got the thread off-topic. But when I saw you mention that your connection was half-duplex and using cable, it jumped out at me.)

 

[PlatinumGold]

All correct, actually. I work for the local phone company here, and my roommate works for the local cable company. I've confirmed these facts with my people and with my roommate. My DSL engineers confirmed that DSL is full-duplex, and my engineers and my roommate both told me the cablemodem service is half-duplex.

I did include a disclaimer in my original message, however, that full-duplex cable COULD arrive eventually. If it has, (which I can confirm with my roommate at Cox,) then you can certainly ignore my original statements.

(P.S. To the original post: Please forgive me if I got the thread off-topic. But when I saw you mention that your connection was half-duplex and using cable, it jumped out at me.)

Correct but IRRELEVANT. he was asking about 100mb internal to his network, what the cable modem does or does not do has no relevance to what happens inside the network w/ the network router, only with the traffic from outside.

 

[Macro2]

Someone said the cable between the modem and the router is a crossover cable? Hummm.

Mac

 

[Snuffaluffaguss]

nope, don't need a crossover to go from cable modem to WAN connection of the router. and yes, you miss wired the Cat5, someone above me posted the correct specs, but straight through won't cut it at 100mbs. make sure the wires are all pushed to back of the connector and use alot of force to make a good crimp.

 

[odog]

All correct, actually. I work for the local phone company here, and my roommate works for the local cable company. I've confirmed these facts with my people and with my roommate. My DSL engineers confirmed that DSL is full-duplex, and my engineers and my roommate both told me the cablemodem service is half-duplex.

hehe.. sounds like telco bred propaganda

tell your buddy at cox to study just a bit more about how the engineering works in a CMTS. cable is 100% most definitely 100% full duplex. the ethernet connector on the modem, thats a toss up. most newer modems have a 100base full duplex ports. many older modem only have a 10base port. not that its even an issue as most modem are capped well below that.


just curious... what is your area?

 

[Macro2]

The most important thing in making cables is a GOOD CRIMPER, for what it's worth.
Also, a $50 cable tester will save you a lot of headaches.

Mac