The industry has been predicting the growth of 10GBASE-T for years, and it’s finally happening. More networks are planning 10G migrations. Why? Due to demand from more advanced devices, users and applications.
But new concerns come into play with this Ethernet standard. Alien crosstalk – the interference caused by wire pairs in one cable inducing noise into other wire pairs in adjacent cables – is the transmission parameter that most significantly impacts 10GBASE-T performance.
Alien crosstalk is a combination of alien near-end crosstalk (NEXT) and alien far-end crosstalk (FEXT); the noise source originates from a common mode signal that is converted onto the differential mode signal through some type unbalance on cable and components.
In high-speed, high-bandwidth applications – used today to accommodate more users and more devices – alien crosstalk can cause many problems. In a cable bundle, it’s possible that cable pairs in one cable pick up interference from pairs of another cable. The digital signal processors (DSPs) used in 10GBASE-T architectures can’t remove unpredictable exterior noise. Noise sensitivity increases at higher frequencies, such as 500 MHz, which is the highest frequency of Category 6A cabling.
This interference isn’t just a nuisance; it has the potential to shut your entire network down – which leads to unplanned downtime, financial losses, a productivity nosedive and unhappy users.
Alien crosstalk originates from a common mode signal that is converted onto the differential mode signal through some type of unbalance on the cable and components. Category 6A cabling and components are designed and tested to reduce alien crosstalk to a level low enough that it does not interfere with the differential mode signal.
Make sure all components are Category 6A>. This is especially important to note for patch cords. When high-quality, Category 6 cable is tested, it may pass Category 6A patch cord requirements because only near-end crosstalk and return loss are measured. When these patch cords are bundled and placed in a Category 6A channel, however, the channel fails alien crosstalk requirements. Why? Because Category 6 cable isn’t designed to handle high data-speed requirements.
Don’t over-tighten cable ties. Cable ties that increase tension can force cables together and impact alien crosstalk. When using cabling ties to dress the cabling, make sure the ties are free to rotate after tightening.
Alien crosstalk reduces cabling’s operational bandwidth due to increased channel noise levels; as a result, ANSI/TIA standards state that Category 6A cabling best meets the demands of 10G. (According to current standards, Class E and Category 6 cabling aren’t recommended for new 10GBASE-T installations over 37m.)
Here are a few reasons why Category 6A is the best choice:
Belden’s Category 6A cabling solutions provide a simple design without compromising performance or quality, ensuring robust performance and reliable networks. Learn more about our 10GXS cables, which feature a smaller diameter, a rounder jacket, a smaller bend radius, fewer twists and easy-to-remove barrier tape.
Ron joined Belden in 2016 to help define the roadmap of technology and applications in the enterprise. Prior to this, he developed cables and connectivity for Panduit and Andrew Corp. Ron Tellas is a subject-matter expert in RF design and Electromagnetic Propagation. He represents Belden in the ISO WG3 committee, TIA TR42 Premises Cabling Standards and IEEE 802.3 Ethernet Working Group. Ron is the inventor of 16 US patents. He has a Bachelor of Science degree in Electrical Engineering from Purdue University, a Master of Science degree in Electrical Engineering from Illinois Institute of Technology, and a Master of Business Administration from Purdue University.