Category 6 vs. Category 5e
Get Reel; May 2009
Category 6 vs. Category 5e is the never-ending debate in the copper cable world. Does it come down to asking, “Is it a need to have or a nice to have?” And, what are some of the decision criteria? Simply put the main advantages are higher bandwidth and better performance. Some of the debate is larger diameter and greater price. Let’s take a closer look and you will see why Category 6 is the best and wisest solution for LAN networks.
Price vs. Cost
Top of the mind issue is budget. There is a difference between cost and price. The difference of materials between Category 6 vs. 5e can be 35%. However, factor in the installation and future proofing and you will find that the value and total cost differentiation is minimal. Looking at the cost of a total network system which includes software, hardware, infrastructure, training and documentation, cable is actually 3% of the total. With that ratio, the cost to upgrade from Category 5e to 6 is actually less than one percent of the total network cost, which is relatively low.
The size of the cable contributes to the size of the pathway and Category 6 is known to have a larger diameter, due to the spline. But, this is a fallacy as many Category 6 cables do not have splines. In fact, Berk-Tek’s LANmark™-6 minimum compliant Category 6 is the same size as LANmark-350™ Category 5e.
Cable balance is an important parameter for high-speed computer network reliability as the better the balance between the conductors of a pair, the better susceptibility to noise and crosstalk. Better balance is directly affected by cable’s physical make-up which is directly attributed to precise manufacturing processes. If the conductor is perfectly centered in the insulation and the pair twists are tighter, then the balance will be better. For example, the typical pair lay of a Category 5e cable ( 1.5” to 4.0”) will deform easier vs. the lay of Category 6a (.250” to 0.500”). In a study at the Nexans Data Center Competence Center (DCCC), several Category 5e and Category 6 cables were tested and compared. Category 6 minimized the number of errors due to noise on Ethernet data traffic, resulting in better balance.
Increased susceptibility to external noise becomes critical with increased data rates, which require higher signaling speeds and more complex encoding. External noise sources such as power lines, air conditioning units, elevators, electrical equipment and interference from adjacent cables generate spikes of voltage, also referred to as electrical fast transients (EFT). EFT can drastically affect the operation of copper cables and create errors. There is a direct relationship between balance and noise immunity. Through proven tests at the DCCC, Category 6 cables demonstrate up to 50% better noise immunity than Category 5e.
Taking the heat
Horizontal cabling is installed in hot areas – such as above the ceilings. Temps can fluctuate as much as 45°F. Once again the DCCC lab conducted testing of 1000BASE-T signals over 90-meter channels of Category 5e and Category 6 in elevated temperatures. The results of the tests showed that there was a significantly higher occurrence of errors at higher temperatures using Category 5e cabling as compared to Category 6.
PoE applications designed to send power and data through the same twisted pair cable, such as Voice over IP phones and security cameras, will eventually need to push more power over the cable. Cable performance tends to degrade at higher temperatures due to greater insertion loss. The industry trend to install higher- grade cables, such as Category 6, which utilize larger conductors, minimizes insertion loss while increasing current carrying capacity.
The Need for Speed
Moore’s law that originally related to the number of transistors in a chip doubling every two years extends itself to translate to almost every measure of electronic transmission – processing speed, memory capacity and even relating to the number and size of pixels on a digital camera. This adage has held true since 1965. Therefore, with increasing capacity for network systems, the reliability will fall on the information transport system, whose basic component is the cabling. Category 5e is the minimum performing copper cable that meets the TIA 568-B specifications at 100 MHz. Category 6 base level standard is defined at twice that at 250MHZ. Whereas premium Category 6 cables can push speeds and bandwidth out to 500 MHz.
If you want your cabling plant to support existing and future applications, the investment in Category 6 is minimal considering the benefits. So, give me one good reason why you would install yesterday’s technology for today and tomorrow’s increasing applications.