A range of network technologies can be used to establish network connections, including Ethernet, Fiber Distribution Data Interface (FDDI), Copper Distribution Data Interface (CDDI), Token Ring, and Asynchronous Transfer Mode (ATM). Ethernet is the most common choice in installed networks because of its affordability and scalability to higher bandwidths.
Ethernet is based on the Institute of Electrical and Electronics Engineers (IEEE) standard IEEE 802.3.Ethernet is based on the carrier sense multiple access collision detect (CSMA/CD) technology, which mandates that transmitting stations standby for a period of time when a collision occurs. Coaxial cable was the initial physical media established in Ethernet standard.
Coaxial Ethernet cable comes in two categories: Thicknet (10Base5) and Thinnet (10Base2). These cables vary in size and length. Ethernet coaxial cable lengths can be long and are prone to electromagnetic interference (EMI) and eavesdropping.
Wired networks typically use twisted-pair media for connections to the desktop. Twisted-pair also comes in two categories: Unshielded twisted-pair (UTP) and Shielded twisted-pair (STP). One pair of insulated copper wires that are intertwined forms a twisted-pair. The pairs are interlinked at the top to diminish interference and crosstalk. STP and UTP are prone to high attenuation so the lines are usually restricted to a maximum distance of 100 meters between devices. Also, these cables have high receptivity to EMI and eavesdropping. 10BaseT UTP Cable is the most commonly used cable.
Another option is fiber optic cable (10BaseFL), which carries light signals produced either by light emitting diodes (LEDs) or laser diodes (LDs) as opposed to electrical signals. These cables execute much higher transmission speeds and extended distances but are more expensive. The benefit of fiber optic is its insusceptibility to EMI and eavesdropping. They also have minimal attenuation which allows them to connect to active devices that are up to 2 km apart. Again, the expense factor of these devices is something to be considered while cable installation is complex.
Fast Ethernet runs at 100 Mbps and is based on the IEEE 802.3u standard. The Ethernet cabling schemes, CSMA/CD operation and all upper-layer protocol operations have been supported by Fast Ethernet.
Fast Ethernet has backward compatibility with 10 Mbps Ethernet. This is possible because the two devices at each end of a network connection can automatically configure link capabilities so that they both can operate at a parallel level. This involves the detection and implementation of the highest common bandwidth and self-negotiating half-duplex or full-duplex operation. Because of this, Fast Ethernet is also known as 10/100 Mbps Ethernet.
Gigabit Ethernet is a modification of the Fast Ethernet standard using the same IEEE 802.3 Ethernet frame format. Gigabit Ethernet has a maximum throughput of 1,000 Mbps (1 Gbps). As with Fast Ethernet, Gigabit Ethernet has compatibility with earlier Ethernet standards. One difference is the physical layer has been adjusted to raise data transmission speeds. The IEEE 802.3 Ethernet standard and the American National Standards Institute (ANSI) X3T11 FibreChannel. IEEE 802.3 provided the basics of frame format, CSMA/CD, full duplex, and other elements of Ethernet.
FibreChannel provided a base of high-speed ASICs, optical features, and encoding/decoding and serialization mechanisms. This protocol is termed IEEE 802.3z Gigabit Ethernet. Gigabit Ethernet accommodates several cabling types, referred to as 1000BaseX.
