Fast Ethernet 100BASE-T is 10BASE-T with the original Ethernet Media Access Controller (MAC) at 10 times the speed. It allows three physical-layer implementations, all part of IEEE 802.3u: 100BASE-TX, which has two pairs of Category 5 UTP or Type 1 STP cabling and is most popular for horizontal connections; 100BASE-FX, which has two strands of multimode fiber and is most popular for vertical or backbone connections; 100BASE-T4, which as four pairs of Category 3 or better cabling and is not common. Gigabit or 1000-Mb Ethernet is the 1998 IEEE 802.3z standard that includes the Gigabit Ethernet MAC and three physical layers. Gigabit uses 8B/10B encoding and encompasses three physical standards: 1000BASE-SX Fiber (horizontal fiber), 1000BASE-LX Fiber (vertical or campus backbone), 1000BASE-CX Copper (Copper-Twinax cabling), and 1000BASE-T.Download whitepaper