What do Cat5e, Cat6, and Cat6a have in common?
All three cable types are unshielded twisted pair (UTP) cables. They each utilize 4 twisted pairs in a common jacket. They use the same style RJ-45 jacks and plugs. And, they are each limited to a cable length of 100 meters including the length of the patch cables on either end of the link. The parts are interchangeable, so you can use a Cat5e patch cable with Cat6 house cabling. Your system will just perform at the level of the lowest link, in this case the Cat5e patch cable.
So what’s the difference?
Better transmission performance. With each upgrade in cable, there is less signal loss, less cross talk, and a larger frequency bandwidth where performance expectations are defined. These are all electrical differences though, and don’t neccessarily translate into faster performance. A common misunderstanding is, if you put in a higer grade of cable, you will get faster network performance.
The reality is, network speed is defined primarily by the electronic transmission equipment (the network switch, etc). A network switch will negotiate the fastest link it can manage, in increments of 10Mbit/s, 100Mbit/s, 1Gbit/s, or even 10Gbit/s.
A switch or NIC card will start off trying for the best speed it is rated for (usually either 100Mbit/s or 1Gbit/s). If the other end, and the cable can’t handle that speed, it will drop down to the next level. So.. if you buy a Gigabit switch, and have Gigabit NIC cards in your PCs, then you’ll get Gigbait speeds so long as your cable supports that.
Here’s what each cable type is rated for:
Cat5e:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 45 meters
Cat6:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 55 meters
Cat6a:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 100 meters
What’s important to note here, is that even Cat5e supports Gigabit Ethernet. So, unless you think you might need 10 Gigabits across a given link, Cat5e will do the trick just fine. Cat5e can even handle 10 Gigabit Ethernet at short distances, so within a server room for example as a backbone link, Cat5e cable is rated to handle it. What’s more likely though, is that you’ll be running any 10 Gibabit connections over fiber.
So which cable should I use again?
Cat5e will give you all the performance you are likely to need today for workstations. Consider that a VoIP call uses 64Kbit/s. Even 1080p streaming video with Dolby Digital Plus audio requires less than 10 Mbit/s. So what on earth we ever do with more than a Gigabit of speed to a single workstation device?
Servers and switch-to-switch links are another story, but you’re also likely to be using Fiber for links of this nature. Just keep in mind that it is your networking gear that defines the speed. The cablign just needs to be able to keep up. So, look at the specs on your network gear and make sure your cable meets what is asked.
What if I might use the cabling for something OTHER than Ethernet?
Unshielded Twisted Pair (UTP) cabling can also be used for analog transmission. When carrying broadband video (CATV), the cable performance has a big impact on signal quality and in turn, the length your cable runs can be. For these sorts of applications, Cat6 may have some value. Of course, Cat6a would be even better but Cat6a is relatively new and the price jump between Cat6 and Cat6a is much steeper than the difference between Cat5e and Cat6. Consult your specific application specifications to see what cable lengths are permitted for each type of cable.