A data-center technician must cable a new top-of-rack switch that provides 10GBASE-T connectivity to 1U servers. Horizontal runs between the switch and the patch panel will average 80 m and will be tightly bundled in overhead trays, so minimizing alien crosstalk is important. Which twisted-pair cable category should the technician specify to guarantee standards-compliant 10-gigabit performance for the full channel length while avoiding unnecessary expense?
10GBASE-T can operate over twisted-pair copper for up to 100 m only when the cabling supports 500 MHz bandwidth and strict alien-crosstalk limits. Category 6A was created for this purpose: it is rated to 500 MHz, includes tighter alien-crosstalk specifications, and is certified for the full 100 m channel at 10 Gb/s.
Category 5e and Category 6 can sometimes pass 10GBASE-T, but only out to about 55 m under favorable conditions; an 80 m run would exceed their guaranteed performance envelope. Category 8 does exceed the frequency requirements but is optimized for 25/40 GbE links and is limited to 30 m, making it unsuitable for typical horizontal cabling and needlessly costly for 10 Gb/s. Therefore, Category 6A is the appropriate and standards-compliant choice.