Cable Management Best Practices

Many years ago I helped install several server racks full of equipment that included routers, switches, storage and servers. My coworker and I were supporting an event at the Javits Center in New York. We spent several days installing and testing all the gear until we were confident it would perform as needed the next morning when the event opened and thousands of attendees would roam through the convention hall. As we gathered our bags to prepare to leave for the evening, a network technician, who worked for the Javits Center, stopped by our area. He wanted to confirm we'd been able to get on our subnet, and that all our networking questions had been answered. We were good to go, but as he walked past our rack of equipment, he casually mentioned he hoped we wouldn't need to call him for support since our cabling looked like a spaghetti bomb had detonated near our racks. We hadn't given a lot of thought to our cable management since this was a 3-day event, and we didn't anticipate any customers peaking behind the curtain. But we realized this technician was correct. If we had to troubleshoot anything during the event, our sloppy cabling could prove to be a major obstacle in getting back online. We put our packs down and spent the next few hours organizing, crimping and tidying up our area. This week, I'd like to discuss some best practices when it comes to organizing and managing cables. A little planning goes a long way, and you can save a lot of time by implementing these practices from the start instead of attempting to organize an already disorganized rack, like we did at Javits. Organizing your cables not only looks professional, but it makes maintenance and troubleshooting much more effective.

Label Every Cable

If you've ever taken over a rack or cabinet full of gear, you probably already know how helpful it is when every cable is labeled at both ends. Labeling even short cable runs is worthwhile, especially if you need to test a number of circuits in a short period of time. I've heard that labeling each cable takes too much time. It's certainly an investment in time, but you get that time back the first time you know exactly what cable needs to be tested instead of wading into a mess of unmarked ones.

A number of companies make label makers. I've tried ones that range from $50 to $300, and find the portable models to be the most convenient because I can take them into tight areas. DYMO makes a number of models that can be operated with one hand and carried in a pocket. Find one that feels good in your hand and one that you'll actually carry. Paying more for a label maker will get you more memory, hotkeys, or color displays. I've found it helpful to use a label maker that allows me to save those symbols and labels I use most often, but that's a feature found even on the less expensive models like the DYMO RhinoPRO 5200.

Use Only Quality Cables

It's only a patch cable. What's the worst that can happen? Actually a lot can happen when you use cheap cables and none of it is good. Cheap cables have a lower than standard copper core which can cause signal loss. Cheap cables also tend to stretch or snap making them more likely to fail. Plus, saggy cables look terrible.  Yes, quality cables will cost more, sometimes double the price of cheap cables. But a good quality cable will last many years and will result in a more reliable network. Copper cables should never be run parallel to electrical cables or they will act like transformers. Quality cables are able to mitigate more interference than cheap cables, but you should plan to put as much distance between your data and power cables as possible.

Use Only Quality Terminations

You don't want to purchase quality cables and then slap crappy terminations on them. Cheap terminations are available but should be avoided because they don't save you any money if they come loose. If you've learned how to properly crimp cables, you shouldn't see a connection drop when you wiggle them. If you do lose connection, cut and crimp again. I've made the mistake of asking a technician who just learned how to crimp to crimp runs back to the core switch. Carpet was then put down before I realized we'd lost connection. You can imagine the massive headache this caused, but I had no one to blame but myself.

Don't Overload Cable Trays

The cable trays that extend from the ceiling should be large enough to so that cables are not crushed. Overloaded cable trays can also become too heavy and pose a danger if they fall from the ceiling. Unused cables should be removed, rather than trimmed at both ends and left in the tray. It never hurts to take an inventory of all overhead cables at least once a year and make sure any abandoned cables are removed. Overhead cable trays are expensive to install but can make organizing your data center a lot easier. One thing I noticed at Microsoft was that if the cable trays were installed within reach of employees, they tended to fill up with cables that didn't belong in the trays such as loose power and KVM cables. An overloaded tray can also result in cables near the bottom being crushed, which will mean a degradation in signal.

Color Code Cables

I know some networking engineers are going to disagree with me on this one because using a single color looks professional. And using a single color might work in some instances, but using different colored cables can help you keep organized and can make troubleshooting much easier if you've taken the time to implement a color standard.

DMZ cables at Microsoft were always orange. Switch to switch cables were always blue. I did some digging in the forums to see if there was any agreement on color coding schemes and quickly realized there are no standards. I assumed crossover cables were always yellow (because Cisco equipment comes with a yellow crossover cable), but that's just not the case. Many admins claimed crossover cables should only be red. Feel free to create your own standard. Maintaining your standard is more important the colors you choose. And avoid purple and pink. Just don't go there.

Mind Your Cable Length

You want a little bit of slack in your cables, but not too much. You don't want to pull cables too tight or they will stretch and place unwanted pressure at the connection point. If your servers are close together and a 1-foot patch will suffice, don't use those extra 3-foot cables you have hanging around. Too much slack invites kinks and cable tangles. Most messy cable jobs I've seen are a result of using cables that were much too long for the job. One options for getting the right cable length is to purchase custom made cables. This can be an expensive option for smaller installations, but having just the right length in large installations can save money from having to crimp hundreds or thousands of cables. I've also heard of some administrators who will position racks at a distance that allows them to use standard-length cables. These are just a few best practices for keeping your data center or server closet neat and tidy. What are some best practices you utilize when it comes to cable management? Photo by twicepix Photo by Collin Anderson