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I just had to run a total of 12 cat5 cables into a patch panel. This was the first time I'd actually done that. I'm reasonably confident that I got all the wires in the right order after some initial A/B confusion, but I'm not entirely confident that all the physical connections are fine. I don't have a reason to suspect that since all the connections I've tested so far have worked perfectly.

What I don't know here is the degree to which connections could fail. If I mess it up just a little bit will nothing work at all or will there be intermittent problems that are near impossible to trace? My company has a very limited budget so we don't have any proper network testing equipment and I'm using a bargain bin $5 manual punch down tool, not one of the fancy expensive ones that tries to eliminate human error.

My testing process so far has been to plug each patched port into the switch then take my personal laptop around to the wall jack I just patched. I plug my laptop into the wall jack and see if it can get an IP from the DHCP server and access the router's DD-WRT management interface. If it can properly send the management interface to me (which is a rather detailed webpage), I've been crossing that off as a working jack.

Is this a decent enough testing process, or is there another (and more accurate) way to test each jack (without network tools, remember).

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5 Answers 5

You are correct to suspect that your $5 network tester is inadequate to the task. It's fine for verifying that your wire map is correct and that the you have connectivity, but it won't detect any of the other problems, like the many varieties of crosstalk.

If you are fine with learning about problems as they occur, you're probably fine with the testing process you described. Another good test would be to push some actual traffic through the wire (iperf on both ends of the wire) and see if any of them run dramatically slower than the rest.

The downside is that when some weird network issue occurs, you'll never be sure if it's your wiring or something farther up the stack.

There are companies that lease test equipment. If you could get your hands on a good Fluke meter for a day, it would go a long way to identifying any of the more esoteric wiring problems.

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Umm, I think he has a $5 punchdown, and no network testing tools... –  Mark Henderson Aug 20 '09 at 22:56
    
D'oh... and 15! –  Insyte Aug 20 '09 at 23:44
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How limited is a limited budget?

$0 budget If you have a technical center in town (highschool votec) they might have a highend fluke that could do the work -- call them and see if its something you could use as a teaching exercise for students and borrow gratis.

$100 budget A 'cheap' solution is to swap out your network switches with (used?) managed switches that can monitor packet loss.

A port that has packet loss = bad drop.

You can pickup really cheap 100base switches that are fully managed, and use something like Cacti to log all packet errors per port over time.

$1000 budget If you have a little more money -- consider asking a local wiring company what they would charge to audit your connections. They have the $1000 fluke that can do the work, and should charge ~$120/h for two people to run the tests for ~05 minutes per drop. They might even 'rent' you the tool.

and I'm using a bargain bin $5 manual punch down tool,

Invest in a 'real' tool. They are like $80 aren't they? I think thats what I paid with a 66 block and a 120 block punchdown (are those the right numbers). It litterally changed my outlook on cabling. I would implore you to even buy it yourself if you have to.

There is also the, "if it isn't broken don't mess with it" school of thought. If you aren't having problems its 'close enough' to working. I have seen some REALLY badly installed drops that drop ~10% of the packets yet still work. Stick with your laptop test, copy a 100mb file off another machine, and call it "good enough" for now.

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IMHO, No. I recommend getting a testing tool that does more than making sure each pin is connected correctly. Check out this question for some good answers:

http://serverfault.com/questions/7441/help-me-fight-this-spaghetti-monster-cabling/7449#7449

I just noticed you mentioning something about not using 'network tools', if that's the case (I'm guessing you don't want to spend the cash for 12 clients - though I/most would definitely argue that), then you might want to look at future releases of the NDT server which is claims to include a feature to detect a bad Cat-5 cable.

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internet2.edu/performance/ndt –  l0c0b0x Aug 20 '09 at 23:09
    
NDT links are dead. –  glenneroo Mar 3 '12 at 12:08
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Every network guy's first investment should be a decent punchdown tool; you can get a workable unit from your local mega-hardware store, most of them have a low voltage/electronics section these days.

After that, as has been said, load-test, beg or borrow some testing tools and definitely look for a managed switch that fits your budget.

And welcome to the party.

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I've also had a couple of tight-fisted clients who assume that setting up this stuff is quick and free, and it is always difficult to convince them that both time and proper tools are required.

That being said, if you can't afford to buy a very nice Fluke cable tester then I'd recommend hiring, begging or borrowing one for a day or two - it will save you a lot of hair later on...

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