Ethernet Protocol

In its most basic form, a network is a connection of two computers, which collaborates on a particular task. The tasks may range from simple file sharing to the complex distributed computing or clustering. The two basic components of a network are the physical medium and the network protocol.

Ethernet protocol works on the baseband networking technology, which has been defined by various standards. Its major elements include packets, access control methods, hardware cables, connectors, and circuitry. This is a dominant network technology, which was developed in phases, at Xerox PARC, between 1973 and 1975.

Its patent was filed by Xerox in 1975, listing Robert Metcalfe, Chuck Thacker, David Boggs, and Butler Lampson as its inventors. This protocol was designed and implemented as a packet-switching LAN over broadcast technology. In 1985, the IEEE 802.3 standard was defined and implemented for it at the Network Interface layer of the TCP/IP model.

Ethernet protocol is most widely used for network connectivity. It uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection), in which the computer in a network listens to the cable, before sending anything through the network.

With CSMA/CD, it is normal to have collisions, as two computers may attempt to send data at the same instance. However, the delay caused by collisions and retransmitting of data is very small, and it does not affect the speed of transmission on the network.

This protocol is applicable for linear bus, star, or tree topology, and the data can be transmitted through it over wireless access points, twisted pair, coaxial, or fiber optic cable, at a speed of 10 Mbps up to 1000 Mbps.

At the beginning of Ethernet implementations, coaxial cables were generally used to connect the stations to each other. The two forms of coaxial cables are 10Base5 and 10Base2 (thick and thin Ethernet respectively).

The latter cable allows connection of up to 30 nodes over a maximum distance of 185m, whereas the former uses 10mm wide coaxial cable, which can connect up to 100 nodes, over a maximum distance of 500m. 10BaseT is also an older standard networking technology, which is used in offices or homes.

It uses cables with wires that are twisted in pairs, and a hub or switch, which allows the connection of multiple computers. 10BaseT can operate at 10 Mbps or 100 Mbps, with a maximum range of 100 meters, and it uses a star physical topology.

1 Gigabit Ethernet allows the data transmission rate of 1 Gbps and is primarily used for backbones on a network. It can be implemented with both fiber optic cables and copper ones. It replaced the Fast Ethernet, becoming a network interface upon new PCs. Other 1 Gigabit cables include 1000BASE-T, 1000BASE-SX, 1000BASE-LX, and 1000BASE-CX.

There are also 10 Gigabit cables, which encompass media types for single-mode fiber, multi-mode fiber, copper backplane, and copper-twisted pair. These cables include 10GBASE-SR, 10GBASE-LX4, 10GBASE-LR, 10GBASE-ER, 10GBASE-SW, 10GBASE-LW, 10GBASE-EW, and 10GBASE-T.

An Ethernet address is the unique hardware address of a device on a network. It is also known as the media access control (MAC) address and is 48 bits long, displayed as 12 hexadecimal digits.

According to Interactive Data Corp. (IDC), in 2008, 350 million Ethernet switch ports were pushed out into the world.

Because of the ubiquity of this technology, and the low cost of the hardware needed to support it, most of the manufacturers now build the functionality of an Ethernet card directly into the PC motherboards, eliminating the hassles of its manual installation by the end user.