Ethernet (IEEE 802.3) is an international standardized network technology that enables computers to communicate with each other in a Local Area Network (LAN).
A simple Ethernet consists of a number of workstations (nowadays mostly Personal Computers) that are attached to a single large cable system, called the Ethernet bus or the trunk. This trunk is shared among all the attached workstations. It is also possible to connect a hub to the bus. Individual workstaton can be attached to the hub in a star-like manner. Ethernet supports a data transfer rate of 10 Mbps.
Fast Ethernet
A newer version of Ethernet, called Fast Ethernet, supports data transfer rates of 100 Mbps.
Gigabit Ethernet
Gigabit Ethernet supports rates of 1,000 Mbps (1 Gbps). This version is mainly used as a backbone to interconnect different LANs.
Gigabit Ethernet can use different types of cable.
1000Base-LX
Long wavelength laser (1300 nm) optical fibres.
Maximum cable length is 316 m in a half-duplex configuration and 550 m in a full-duplex configuration.
Can be extended to 5000 m if a very thin (10 µm) single mode fiber is used.
1000Base-SX
Short wavelength laser (850 nm) multi-mode optical fiber.
Maximum cable length is 275 m on a 62.5 µm fiber cable.
With a 50 µm fiber cable a length of 316 m in a half-duplex configuration or 550 m in a full-duplex configuration can be reached.
1000Base-T
Four pairs of 100 Ohm unshielded twisted pair, category 5.
Maximum cable length is 100 m.
1000Base-CX
Shielded twisted pair.
Maximum cable length is 25 m.
Gigabit Ethernet is defined in IEEE 802.3z and 802.3ab (1000Base-T).
The latest version of Ethernet can even handle data rates of 10 Gbps. The 10 Gigabit Ethernet version is defined in IEEE 802.3ae
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