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It seems like no matter how strict and careful we are in our closets when we set them up, they eventually turn into a giant knot.

In part I blame the fact that we've got a rather large number of people who go into the closets and move things around, but I can't really change that.

What I can change is the way we arrange our racks and patch panels and switches.

At the moment, we've got the patch panels in a group (with wire managers between them) and a feet below them we've got our switches.

I'd like to just pull out the cable managers and put the switches directly below the patch panels, and connect the switches to the patch panels with 6 inch cables.

Are there any problems with using 6 inch patch cables?

bad way to run a network

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Nice twist tie holding that mass of gray cables on the right. Did it come from a loaf of Wonder bread or a package of Lender's bagles? :) –  joeqwerty Aug 11 '10 at 23:23

8 Answers 8

up vote 3 down vote accepted

Personally, I try to put the switches as close to the patch panels as possible. Typically, I'll put a 48 port switch between 2 24 port patch panels. So it goes like:

Patch Panel
Switch
Patch Panel
Patch Panel
Switch
Patch Panel
...

Then, I use 6" patch cables to connect the panel to the switch. The benefit is that everything is nice and neat, and organized... Then, any infrastructure related cabling (connecting switches, etc) I run out to the side of the rack and then up/down to where it needs to go...

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Have you had any issues with this? Have you run these links at gig? I've noticed that you can't get 6 inch cat6 cables, I assume because there are minimum length requirements for the cat6 spec, but I've got no real evidence one way or the other. –  chris Feb 16 '11 at 15:31
    
And do you have any photos? –  chris Feb 16 '11 at 15:35
    
@chris: I've never heard of a minimum length (but I'm not an authority on the matter). And I've never had an issue running 1000bTX auto-negotiated over those 6 inch Cat5e patch cables (not a single dropped packet). It shouldn't be an issue at all with that short of a cable (as long as it's a good cable)... And no, I don't have any photos right now (everything needs to be redone after a switch failure required some "jury rigging" of things to get it all to work again... –  ircmaxell Feb 16 '11 at 15:39
    
Did the 6 inch cables hinder or help the jury-rigging? I can imagine situations where using long cables properly routed may allow you to plug certain devices into other devices in the event of a failure, while you wouldn't be able to do that with short cables. –  chris Feb 16 '11 at 20:36
    
@chris: helped. Definitely helped. Mainly because it was organized enough that I didn't need to go rerouting cables all over the place. Some of them had to be replaced with longer cables, but I had them around anyway (for other uses, 1 and 3 footers)... –  ircmaxell Feb 16 '11 at 20:39

I would also like to also suggest getting patch cables in different colors. Each color could be for a department, vlan, printers, servers, voip, etc.

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+1. Good idea. Having a visual clue as to what type of device\network the cable connects to can be a real help when looking for one cable in a mass of hundreds. –  joeqwerty Aug 11 '10 at 20:48
    
+1. I do the same. Yellow is for standard network devices (computers, printers, etc). Blue is for POTS lines. White is for VOIP phones. Blue is for network interconnects. Red is for untrusted (outside of the firewall, DMZ, etc). And each server has its own color (that's our naming scheme anyway) applied to its network cables via colored electrical tape on both ends. –  ircmaxell Aug 12 '10 at 12:24

I have no problem using any patch cable that fits the application. If I need a bundle of 10' cables, or 24 6' ones to go from one panel to the switch, fine with me.

On a personal note, I prefer to run cables from the patch panel down to the switches, rather than have longer cables that go off horizontally, then down the side edge of the rack, then horizontally into the switch.

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Surely 6 inch cables are just too limiting, get the longest ones you can and loop them together to keep things tidy.

Like this:

alt text


or.. make or buy (if you can) some cables that are just long enough (but not so short that you put strain on the plugs - give it an extra inch or two for wiggle room). Our cables tend to be the long ones, but they are all pulled to the side, kept together and the other end pulled in - like you have a box of cabling at the side of the rack to store the main cable, pulling the ends out. That's tidier in many respects as you can still get your hands in there to change them, the cables aren't in the way. This is the main reason I can think of why very short cables would be a disadvantage. Similar to what you show in your pic, but a lot more disciplined - no cable gets added that isn't first put with the bundle on the side. Don't forget to label both ends though!

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I have seen that picture lots of times, but always wondered where it came from. I have always been curious how something could get that bad. –  Zoredache Aug 11 '10 at 20:16
    
Bad? You should have seen it before the wiring reorg. –  joeqwerty Aug 11 '10 at 20:49

They sound like the ideal solution to your problem - assuming that you can get everything 6 inches apart.

If not you could just make some custom length cables that are just long enough for where things currently are.

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I recommend 24" cables and putting the switches above/below/between the patch panels they will service. Given that most racks are 19", this gives you enough room to run a cable from one side of the rack to the other (if necessary), while reducing the slack you have to deal with. Using shorter cables is fine, until you need to recable something, or move a patch port to another switch port, then you're stringing in a new cable. Admittedly it doesn't reduce slack nearly as much as 6" cables would, but the down-the-road flexibility is much handier, IMHO.

That said, for stuff that you're going to set and forget, doing a quick mock up of the rack(s) in question, figuring out the best paths and runs, then either custom-cutting/testing the cable yourself, or overnighting some close-to-length cables from someplace can make an otherwise ugly situation look incredibly nice. I did this with the last rack deployment I did, going as far as to get shorter power cables and color-coded Cat5 (for DRAC, Public vs private network, etc). The back of the rack looks clean, simple, and awesome. not to mention well-ventilated.

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This really seems to be a common way of doing things, and I've seen it done well. It seems to be the approved of "panduit" way of organizing a rack, but in an organization like ours where lots of people make changes in racks, I'm afraid the 2 foot patch cables will get turned into a knot eventually. –  chris Aug 15 '10 at 23:45
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Honestly, that's where you need some SOPs in place and stop letting just anybody touch the racks. –  peelman Aug 16 '10 at 12:46
    
easier said than done -- the patches are often done by helpdesk support people who don't do it often, don't have to maintain it when it gets bad, and frankly don't care. And saying "they should care" is true enough, but hard to actually mandate. And if we made them clean up the mess, they'd make things bad enough that we'd have to fix it anyhow. Kinda like a toddler... –  chris Feb 16 '11 at 15:35
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Hence my point about how they should stop doing it. At my old job the only people with access to the racks were the network engineers and their delegates, i.e. very few, well trained, accountable people. You needed something changed you went through them. Business processes don't always want to change to a model like this though, at least until something bad enough happens that they see the light. –  peelman Feb 16 '11 at 17:48

The main downside with a cable as short as 6" is that you may end up with problems if you use it to directly connect two interfaces, but for a patch between a panel and a switch (or two panels), it should be just fine.

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Are there problems with directly connecting devices because there are minimum distance requirements in the ethernet spec? –  chris Feb 16 '11 at 15:33
    
I don't believe there's a spec for minimum distance in the xBase-T standards, but there is a practical shortest limit that depends on the equipment. There are minimum distances between taps on 10Base-5 and I believe there is a minimum distance between T-connectors in 10Base-2. However, I doubt those are frequently deployed, these days (and I suspect most legacy installatiopns have been converted by now). –  Vatine Feb 17 '11 at 16:28

Your basic problem is a complete lack of a methodical approach to cabling. The use of such absurdly long patch leads, as shown in the photo, just makes it near impossible to be properly organised.

Before you touch another cable sit yourself down and give serious though to the result you want, rather than how to fix what you have. If you don't have a final objective everything you do to that cabling will still end up messy and hard to work with.

One of the most important things to consider is how you are going to know which cable connects to which end points, without having to trace that cable. I use a MS Access database for that, because it's easy to use and I can produce reports in any convenient format. Several of those reports are printed out and hung on the rack. Any cabling changes get updated on those sheets and later entered into the database.

As to the cables themselves, I prefer to make my own to whatever length is called for. If you don't want to do that I suggest getting a bunch of different lengths and using the appropriate one each time. There's certainly nothing wrong with 6 inch cables in and of itself, if that's appropriate to the situation in which they are used.

Her's a shot of part of a rack I tidied up.

Tidy Cables

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How old is that rack and how much churn is there on that rack? The rack with the comically ugly wiring "organization" is about 5 years old and sees pretty constant change (though of only a small number of the ports). Everything looks great the first month it's in service... –  chris Aug 13 '10 at 18:03
    
@chris, the rack in my photo was installed in 2000 when the company relocated. When changes are required we look up the endpoints and work with the appropriate cable(s), ensuring everything is tidied up afterwards. You should be able to spot at least a few cables that have been moved around. There's even a splitter to quickly add a temporary extra port for a user. The reason the rack stays tidy is a combination of an organised approach and a bit of self discipline. I no longer work there but have been told that my successor maintains it the same way. –  John Gardeniers Aug 13 '10 at 22:04
    
1. you're answer of "be like me and try harder" isn't actually all that helpful. 2. the rack pictured above isn't all that dense. Manage 100 of those 2 post rack with double the number of cables in less than the above space and put them into retrofitted broom closets, and have untrained helpdesk people manage adds and changes, thenn tell me about "a complete lack of a methodical approach to cabling". –  chris Aug 15 '10 at 15:54
    
@chris, I have indeed answered your question of "Are there any problems with using 6 inch patch cables?". If you don't like being told you're not managing your cables very well perhaps you should refrain from posting a photo demonstrating that fact in future. –  John Gardeniers Aug 15 '10 at 21:33
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One thing I've always found is that once you get a panel to a nice, clean state, it's easier to motivate yourself to take the time to keep it that way. When the rack is sloppy, you're more likely to just "stick another cable in there" without taking the time to do it neatly. By contrast, once we cleaned up all our panels, we'd always take the time to carefully run a new cable, take apart all the velcro and add the new cable to the bundles and then put the velcro back . –  Ward Jan 18 '11 at 2:47

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