My employer is moving to a new building and i'm in charge of creating/moving the IT infrastructure. There are 3 floors with a patch closet on each floor, then CAT5 uplinks down to the server room on the first floor. The uplinks are run down the wall and are coming into the server room through the floor.

The previous owners decided to cut the CAT5 uplinks in the server room and now they are too short to reach the patch panel in my rack. I figure i have 3 options here and I was wondering what you all thought would be the best solution.

  1. Terminate the CAT5 in the floor, then run a patch cable to the patch panel
  2. Terminate the CAT5 in the floor, then run a patch cable directly to the switch (skip the patch panel)
  3. Run a new uplink.

Any suggestions would be helpful. Thanks!

  • Possibly consider running fiber between your patch panels. – Zoredache Apr 4 '11 at 17:32
  • Thanks for the help everybody. Looks like i'll be running new cable. – Stephen Apr 5 '11 at 14:29

In order of preference:

  1. Run new Cat6 uplinks - preferably with shielded cable, terminating them at a patch panel.
  2. Run new Cat6 uplinks - preferably with shielded cable, terminating them directly on the switch.
  3. Terminate the existing Cat5 in the floor and run patch cables to your patch panel.
  4. Terminate the existing cat5 in the floor and run patch cables directly to the switch.

Re-using the existing cable may be a great way to save time, but depending on the quality of the cabling work done before (and how much damage the cable suffered when it was cut) you may just be setting yourself up for more problems down the line.

In my opinion since you are building out a new infrastructure (in a building you may be in for a while) your budget should allow you to Do It Right (with Cat6 cabling, cat6 patch panels, etc.) to give you as much of a future-proof installation as possible. Along the same lines, if you pull new cat6 cables you may also want to pull fiber-optic cabling with it to allow for future expansion.
Consider how much traffic you may have moving between floors eventually and size your uplinks (physical cable/capacity and switching capacity) generously above that (I'm sure others will chime in with rules of thumb, but I try for at least 2x what I'll need today, in the hope that it will last until tomorrow...).

  • 1
    Why Cat6 over Cat5e? Other than possibly better noise isolation, Cat6 won't do anything that Cat5e can't already do for much cheaper. If you want an upgrade path to 10GbE, then you'd need to go all the way to Cat6e I believe. – EEAA Apr 4 '11 at 17:19
  • My recommendation for Cat6 (or 6e for a 10GbE path as you mentioned) is really for the shielding -- I've had several installations where cable risers were shared with Low-V AC or mechanical equipment and "hilarity" ensued... – voretaq7 Apr 4 '11 at 17:55
  • @vortaq7 - for that case, yes, Cat6 is surely the way to go. – EEAA Apr 4 '11 at 17:56
  • CAT6a is what's needed for 10Gbe, but otherwise +1 for a good answer. – joeqwerty Apr 4 '11 at 17:58
  • @joeqwerty - yes, Cat6a is what I meant, not 6e. – EEAA Apr 4 '11 at 18:00

I'd probably go with #3. It's the most annoying, and expensive, but the least likely to come back and bite you in the ass.

I'd probably also write a rude letter to the previous owners, telling them that they did a very stupid thing.

  • It gets worse. The previous owners did home runs to each computer, so there were a lot of cat5 running out of the walls. The realtor decided that it looked bad and had them cut. So, what could have been a somewhat decent setup turned into a nightmare. – Stephen Apr 4 '11 at 17:46
  • Is it too late to try and find a different office building? – Tom O'Connor Apr 5 '11 at 9:26
  • yep, too late. Most of it is salvageable, but still a lot of extra work. – Stephen Apr 5 '11 at 14:28

I'm going to go with option 3, there's nothing that helps me sleep better than knowing, not suspecting, that my cabling is good. But before you do that I'm slightly worried about your overall cable lengths, what is your longest run with the setup you're suggesting?

  • I don't have an exact measurement, but the building is 3 stories high and not a straight shot between server room and patch closet. My guesstimate is 50ft. – Stephen Apr 4 '11 at 17:51
  • ok, that's fine in itself but I guess I'm more worried about length between switch port and NIC - is that longer? – Chopper3 Apr 4 '11 at 17:57
  • brings up a good point - if your runs are getting toward the long side you may need to add per-floor (or per-department) switches -- This means more physical/logical infrastructure to get your data back to the main server room & is worth pondering... – voretaq7 Apr 4 '11 at 18:06
  • ah, sorry, i misunderstood. Each floor has a patch closet where an edge switch will be. Then there is an uplink down to the server room. It's the uplink that is too short for my rack. – Stephen Apr 4 '11 at 21:25
  • thanks for the update, just worried but you put that worry to bed ;) – Chopper3 Apr 4 '11 at 22:31

In my experience, and opinion, home runs are always best. The more times you terminate, the more room for issue at some point.

  • True, but there are benefits to a structured cabling system with patch panels too (the size at which the benefits of patch panels and structured cabling outweigh the cost and added complexity is a matter of debate, but in my experience 3 floors may be getting close to that point if the environment is complex...) – voretaq7 Apr 4 '11 at 17:12
  • Option 3. Remember to terminate the ends with as little un-twisting as possible. As little as one inch of untwisting can drop the cable an entire rating (e.g. cat5e -> cat5. cat5 -> cat3). Also, depending on local building codes, you may be required to use plenum cable. – Joe Apr 4 '11 at 17:23

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