Millennials who entered the workforce between 2003 and 2016 are used to the digital age: high-speed Internet access, smartphones, online everything. And while they have certainly experienced technological advances throughout their lives, they may not be aware of how far copper Ethernet cabling has come to make it all possible. The following is a small history lesson in Ethernet for the younger generation and a walk down memory lane for those who have been in the industry a little longer.
Explanation of categories of Ethernet cables The first version, 10BASE5, featured an extremely stiff cable nearly half an inch in diameter, and was later joined by 10BASE2, using cable half as thick and much more flexible. In the late 1980s, the development of the Ethernet hub, and later the switch, allowed twisted-pair copper cables to become the primary means of supporting Ethernet.
Categories 3, 4 and 5
In 1989, Anixter, a distributor of cabling products, introduced the “Levels” program, the first written performance specification for data cabling systems. This became the basis for the first category cable based on official standards, ratified in 1991 by the Telecommunications Industry Association (TIA)as Category 3. It supported 10 Mb/s (on two of the four pairs in a Category 3 cable) and paved the way for the evolution of twisted-pair category cables over the next 30 years. Although no longer recommended by industry standards, Category 3 still has an installed base in some commercial buildings for voice. (In some of these earlier installations, you will find that two pairs are used for data and the other pairs are used for another connection or voice pair.) After Category 3, Category 4 was around for a moment, then quickly replaced for Category 5, both now defunct and no longer recognized in cabling standards.
Categories 5e and 6
Around 2001, Category 5e arrived with better crosstalk performance to support gigabit speeds. Then came Category 6 with a bit more headroom, allowing it to support 10 Gb/s, but only up to 35 meters. With qualification testing, some installed bases of Category 5e and Category 6 cables can support 2.5 and/or 5 Gb/s to 100 meters for Wi-Fi 6 deployments, with the potential to support 10 Gb/s to 55 meters or less.
Category 6A
Category 6A, capable of supporting from 10 Gb/sa 100 meters, was ratified in 2009. It remains the recommended medium for all new horizontal LAN deployments. Although it has been around for more than a decade now, Category 6A was perhaps a bit ahead of its time; only in the last five years have common LAN applications required speeds of 10 Gb/s at the end device, and there are still many that operate at 1000 Mb/s or less.
Categories 7, 7A and 8
Potresti anche essere curioso della Categoria 7 e della Categoria 7A, ratificato da ISO/IEC rispettivamente nel 2002 e nel 2010. Sebbene non sia mai stata ufficialmente riconosciuta dal TIA, la Categoria 7A rimane un popolare supporto di cablaggio preferito per supportare 10 Gb/s in alcune parti d’Europa. Poi c’è la Categoria 8, che ha avuto molto clamore come soluzione per supportare 25 e 40 Gb/s in collegamenti da switch a server di data center di 30 metri ma non è del tutto decollata: il consumo di energia è rimasto un problema per 25 /Apparecchiature attive 40GBASE-T. I progressi nella tecnologia del ricetrasmettitore ora consentono anche ai data center di supportare facilmente collegamenti switch-to-server da 25 e 50 Gb/s utilizzando cavi ad attacco diretto SFP28 o SFP56 in configurazioni top-of-rack (ToR) a portata corta o gruppi ottici attivi e fibra cablaggio strutturato in collegamenti più lunghi. Ciò non significa necessariamente che la categoria 8 sia morta.
