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Ethernet Cable Identification and Use: Cat. 5, Cat. 5e, Cat. 6, Cat. 6a, and Cat 7

So you've got a bundle of ethernet cables and you're not really sure if you should use them in your network, this short guide should help you identify and correctly use any of the common ethernet cables you are likely to run across.

First ID the Cable

Category 6 Ethernet Cable Category 5 Ethernet Cable Category 5e Ethernet Cable
As you see above almost all ethernet cabling has the category of cabling printed on the side (hover over an image for the caption). The category tells us what the cable is able to be used for. If you encounter anything other than the categories listed in the table below, you probably should not use them for your network.

Below you can see that the various categories of cable can be relatively reliably identified by the end connector and the diameter of the cable, however, this is not a be all end all. In general a higher category of cable is thicker because it uses thicker wire for better transmission quality. If you are at all unsure, always check the printing on the side of the cable.

Image of Cat. 6, Cat. 5e, Cat. 5, and a standard telephone cable
From top to bottom: Cat. 6, Cat. 5e, Cat. 5, and a standard telephone cable for comparison.

Common Ethernet Catogories, Speed, and Usage

Type Speed Info
Cat. 5 10/100/1000MbE* Category 5 cable is a currently outdated standard that provides a minimum of 100Mhz of bandwidth. It can be used for 10/100 Ethernet without worry, however for longer runs of 1000MbE it is recomended to use Cat. 5e or higher.
Cat. 5e 10/100/1000MbE Category 5e cable provides a minimum of 100Mhz of bandwidth. Cat. 5e generally provides the best price for performance, however for future proofing Cat. 6 or Cat. 6a might be a better choice as they usually do not cost that much more.
Cat. 6 10/100/1000MbE
10GbE*		 Category 6 has a minumum of 250 MHz of bandwidth. Allowing 10/100/1000 use with up to 100 meter cable length, along with 10GbE over shorter distances.
Cat. 6a 10/100/1000MbE
10GbE		 Cat. 6a or Augmented Category 6 has a minimum of 500 MHz of bandwidth. It is the newest standard and allows up to 10GbE with a length up to 100m.
Cat. 7 10/100/1000MbE
10GbE/100GbE		 Cat. 7 is a future cabling standard that should allow for up to 100GbE over 100 meters of cable. Expected availability is in 2013. It has not been approved as a cable standard, and anyone now selling you Cat. 7 cable is fooling you.

Notes:

MbE stands for Megabit Ethernet, 100MbE means that the cable can carry 100 Megabits per second of Ethernet trafic.
GbE stands for Gigabit Ethernet, 10GbE is equivalent to 10000MbE.
* Speeds marked with a star are possible over a short run (less than 10 meters) on that category, however for longer runs up to 100m it is reconmended to use a higher quality cable.

General Tips When Handling Ethernet Cabling

  • Do run cables over distances up to 100 meters with their rated speed.
  • Do mix different cable types as long as the minimum cable category supports the maximum speed of your network. As noted in the table above, all the cables are backward combatible with prior ethernet standards.
  • Do make your own cable if you need lots of varying lengths. More information can be found here.
  • Do buy cables that have no-catch connectors, as seen in the two left-most images of Cat. 6 cable below (hover over the image for the caption). A no-catch connector won't snag on carpets, clothing, and other cables when you are installing it. The right-most image indicates a traditional connector.
    Category 6 Ethernet Cable with no-snag connector Category 6 Ethernet Cable with no-snag connector Category 5e cable with traditional snagging connector
  • Don't order anything less than Cat. 5e cable.
  • Don't use cable in your network if it is rated less than the maximum speed of the network.
  • Don't buy cable from retail stores. BestBuy sells 25' of Cat. 6 cable for $30, you can buy the same from online stores for ~$10 shipped.
  • Don't buy overpriced "super-high-quality" cable. This $500(!) cable comes to mind. If a cable is rated as Cat. 5e then it will perform at that rating.
  • Don't crimp or staple cable, this can easily cause breaks in the cable which are sometimes hard to track down.
  • Ethernet cables are not directional in any way, you cannot install one backwards.
  • Lighter colored cables are usually a better choice for two reasons: They are easier to see in the dark, and it's easier to read the cable catogory stamped on the side.
  • Use a patch cable when connecting a computer to a router or hub, use a cross over cable when connecting two computers directly together. If you are unsure, buy a patch cable, if the cable is not labled as "patch" or "cross over" it is a patch cable.

Kevin Castor Jul. 10th 2008 kcas88@gmail.com
Last Updated Jul. 21st 2008

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