ore-are baseband Ethernet LANs. IEEE 802.3 is the working group that creates and defines the entire family of Ethernet standards (see Table 6.2). The major milestones include the first genera- tion, which emerged in 1983 as the IEEE 802.3 standard and defines 10Mbps Ethernet over thick coax. Later, in 1995, 802.3u introduced 100Mbps or Fast Ether- net. The next major leap occurred in 1998, producing the 1Gbps Ethernet standard, 802.3z. The latest formalized standard, 802.3ae, approved in 2003, specifies 10Gbps Ethernet. In 2004, 802.3ah specified 1Gbps Ethernet for use in the local loop. Ethernet is now also making inroads into the metro and long-haul networking spaces. Full-duplex operation and Ethernet switching have lifted the CSMA/CD dis- tance limitation restrictions, so Ethernet is no longer technically restricted to just Table 6.1 Traditional LAN Standards Characteristic Ethernet Token Ring Standard IEEE 802.3 IEEE 802.5 ANSI X3T9.5, IEEE 802.6 Logical topology Physical topology Bus, star Ring, star Dual ring, dual bus Media Coax, UTP, STP, fiber Coax, UTP, STP Fiber (CDDI) Transmission mode Baseband Baseband Baseband Bandwidth 10Mbps, 100Mbps, 4Mbps, 16Mbps, 100Mbps 1Gbps, 10Gbps 100Mbps, 1Gbps Media access Nondeterministic Deterministic Deterministic Control CSMA/CD, CSMA/CA Token passing Token passing LAN Characteristics Table 6.2 802.3 Ethernet Standards Ethernet Standard Date Completed Description Experimental 1972 (patented 2.94Mbps over coaxial cable bus. Ethernet in 1978) Ethernet II 10Mbps over thick coax. Frames have a Type field. The Internet (DIX v2.0) Protocol suite uses this frame format on any media. IEEE 802.3 10BASE5 10Mbps over thick coax; this is the same as DIX except the Type field is replaced by Length and LLC fields. 802.3a 10BASE2 10Mbps over thin coax (thinnet or cheapernet). 802.3b 10BROAD36. 802.3c 10Mbps repeater specs. 802.3d FOIRL (Fiber-Optic Inter-Repeater Link). 802.3e 1BASE5 or StarLAN. 802.3i 10BASE-T 10Mbps over twisted-pair. 802.3j 10BASE-F 10Mbps over fiber. 802.3u 100