CAT 5e, 6, 6A and Optical Fibre… What’s the difference?

Choosing the right media and category of networking cable can be a tricky task. Category 5e through to 6A look almost identical to everyday people, but there are some subtle differences; some visible and some not.

The most important difference between the cables is the speed and distance in which they operate most effectively. Speed and distance have a direct relationship when it comes to network cables and it’s these two characteristics that differentiate cabling requirements.

So what is the difference between CAT 5e, CAT 6, CAT 6A, and Optical Fibre?

CAT 5e
An upgraded version of Category 5 twisted pair cable, with the “e” standing for enhanced, this cable is a cost-effective choice as it allows for data to be transferred at a rate of up to 1000 Mbit per second (gigabit Ethernet) whilst operating at a frequency of 100 MHz. CAT 5e cables can be run up to a maximum of 90 meters in a single run, with an allowance for a total length of up to 6 metres of patch leads at either end.

Shorter links can accommodate longer patch leads but these should always be kept as short as possible. Whilst the cabling system is able to support 100Mbit transfer rates, the actual speed of the network may be slower due to the protocol being used and the levels of network congestion.

CAT 6
Category 6 cable was developed as a higher level cable that could address actual network throughput speed. This copper cable has more stringent crosstalk specifications and a larger conductor to allow for improved performance at higher frequencies.

Capable of operating at 250 Mbit per second on all four pairs at the same time, this type of cabling is able to support 1GBit transfer rates.

CAT6 cables can be used in CAT 5e systems making them backward compatible and offering future proofing in the cable installation. As for CAT 5e cables, the maximum single run length is limited to 90 metres with a 6 metre allowance for patch leads at either end.

CAT 6A: 
By qualifying the performance of CAT 6 cables up to 650 MHz, transfer rates of up to 10 GBit per second can be supported.  Traditional CAT 6 cables have a number of shortcomings that make their widespread use in this application limited, as a result an improved or “augmented” cable was developed; CAT 6A.

The main issues needing to be addressed included improved control of return loss and improved cross talk performance at the higher frequencies.

Crosstalk between cables, known as alien crosstalk, also became a more significant issue. Originally identified as a problem in early CAT 6 cables, alien crosstalk was exacerbated by the higher frequencies found on the 10GBit systems. To address this a number of different options have been tried including thicker and unique jacket profiles to increase the separation distances on UTP cables as well as various screened options.

Screened options are considered more secure and are generally preferred although grounding issues may require additional care in this type of installation.
As with CAT 6, CAT 6A installations are backward compatible and also limited to 90 metre maximum run lengths with the same 6 metre patch lead allowance. Some CA 6A UTP installations are limited to 30 or 40 metres and you will need to consult with your cable provider to confirm.  

Optical Fibre
Unlike copper cable, optical fibre cables are made of strands of flexible glass, as thin as human hair, that are drawn from molten silica. These strands carry digital signals as light. Even though these cables are made of glass, they are not stiff and fragile. They can bend, much like wires, and are very strong. There are two basic types of optical fibre – single mode and multi mode.

The advantages to optical fibre cables are numerous, they can be run for longer distances, are immune to electrical interference and disturbances, offer increased security and they can take much less space in cable pathways.
Optical fibre has a bandwidth capability of 400MHz/km or greater. This enables optical fibre to provide data transmission performance up to 10Gbps, 40Gbps and even 100Gbps with new hardware that is now available. This provides network designers an easier path for bandwidth upgrades in the future. 

Some may state that the downside to optical fibre is the cost; however, the cost for fibre cable, components and hardware has been on the decline. Installation costs for fibre are still higher than copper because of the skill needed for terminations. This makes fibre more expensive than copper in the short run, but it may actually be less expensive in the long run. Fibre is typically more cost-effective to maintain, has much less downtime and requires less networking and re-generation hardware.

If you have any questions, contact your Madison rep today and they will be happy to discuss the best solution for your needs.