Cat 6a UTP vs. Cat 6a F/UTP in 10 Gigabit Ethernet

10 Gigabit Ethernet is a networking technology for data transmission at a rate of 10 Gbps. To achieve 10 GbE, either copper or fiber cabling is available. Because of its bandwidth, higher-grade copper cables are needed, such as Augmented Cat6 (Cat 6a) or Cat7. This tutorial will introduce Cat6a cabling solution for 10 Gigabit Ethernet.


Introduction of Cat 6a Cable

Cat 6a is a 4-connector twisted pair copper cable. It can support the distance up to 100 meters at 10 Gbps data rate. So Cat 6a cabling system is ready to support 802.3an 10GBASE-T standard released by the IEEE, which specifies 10 Gbps data transmission over four-pair copper cabling.

Cat 6a extends electrical specifications to 500 MHz from 250 MHz for Cat 6 cabling. Cat 6a cables are fully compatible with previous cable including Cat6 and 5e. But Cat 6a cable is different from those cables. It has larger outer diameter, corresponding larger minimum bend radius, and heavier weight. There are two kinds of Cat 6a cable: Cat 6a F/UTP (an overall foiled shielded over four unshielded twisted pair) and Cat 6a UTP (unshielded twisted pair).

As networks transitioned to twisted-pair Ethernet, unshielded twisted pair cabling became the standard, especially in the United States. Because UTP cable is relatively inexpensive and easier to terminate and install than shielded cable. But this is not the case with Cat 6a.

Alien Crosstalk

Before discussing Cat 6a cable in 10GbE network, let’s discuss about alien crosstalk which is a critical and unique measurement in 10GbE network. Crosstalk, measured in 10/100/1000BASE-T systems, is the mixing of signals between wire pairs within a cable. Alien Crosstalk is the measurement of unwanted signal coupling between wire pairs in different and adjacent cables or from one balanced twisted-pair component to another. The Alien Crosstalk can be influenced by a number of factors, including the type of cable, cable jacket, cable length, cable twist density, proximity of adjacent cables and connectors.

Cat 6a UTP and 10 GbE

Cat 6a UTP is designed in a certain way to minimize Alien Crosstalk so that it can support the distance up to 100 meters in 10 GbE network. This includes large conductors, (23 AWG minimum), tighter twists, an extra internal airspace, an internal separator between the pairs, and a thicker outer jacket. Thus the outer diameter of the cable is increased. Cat 6a UTP cable can have diameters up to 0.35 inches. The increased diameter creates a greater distance between pairs in adjacent links. So it reduces the between-channel signal coupling. But Cat 6a UTP is still influenced by Alien Crosstalk.

Cat 6a F/UTP and 10 GbE

Tests have shown that Cat 6a F/UTP cable has a better effect in eliminating Alien Crosstalk than Cat 6a UTP and thus provides more headroom for 10 GbE over copper. The foil shield plays as a barrier preventing EMI/RFI (electromagnetic interference/radio frequency interference) from coupling onto the twisted pairs from other adjacent cables. Besides, the foil shield prevents data signals from leaking out of the cable, making the cable more difficult to tap and better for safe installations.

Cat 6a UTP vs. Cat 6a F/UTP

Cat 6a UTP cable has a larger outside diameter than Cat 6a F/UTP cable. The outside diameter of Cat 6a UTP is 0.354″ and 0.25~0.30″ of Cat 6a F/UTP cable. Though the difference seems minute, it creates a great difference in the fill rate of cabling pathways and spaces. If the outside diameter increases 0.1″, it means a 21% increase in fill volume. In summary, Cat 6a F/UTP cable can provide at least 35% fill capacity than that of Cat 6a F/UTP cable.


In addition, using Cat 6a UTP cable can reduce the density of patch panel connections. Thus, it will increase costs by requiring more equipment, more pathways, much more careful cable installation, and lengthy testing procedures because of Alien Crosstalk.

But for Cat 6a F/UTP cable, not as people always think, it’s easier to handle, requires less space to maintain proper bend radius, and uses smaller conduits, cable trays, and pathways. And terminating Cat 6a F/UTP is easier than terminating Cat 6a UTP cable.

Advantages of Cat 6a F/UTP

In general, using Cat 6a F/UTP has some advantages over Cat 6a UTP in 10 GbE network:

1. Shielding eliminates Alien Crosstalk and EMI/RFI problems and testing;

2. Shielding enhances the data line security;

3. It’s lighter, slimmer and can provide higher port density;

4. Small outside diameter cable is easier to handle and reduces installation costs;

5. Shielded cable uses less space in conduits.


10 Gigabit network is the main driver of Cat 6a cabling system. This cabling system is well applied in data centers, bandwidth service providers, factories, and high-performance switches. Both Cat 6a UTP and Cat 6a F/UTP can support 10 Gbps. The above content shows there are some advantages of F/UTP cable, such as eliminating alien crosstalk. But it doesn’t mean that UTP has no advantages. Today, some people prefer UTP and some prefer F/UTP. Because UTP is for installations where no noise is present and F/UTP is recommended for installations in noisy environments. FS.COM offers both kinds of Cat 6a cables for your applications. For more information, please contact via



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