Ethernet is a set of technologies and protocols that are used primarily in LANs. It was first standardized in 1980s as IEEE 802.3 standard.
Ethernet can be broadly classified into two types −
Classic Ethernet is the original form of Ethernet that provides data rates between 3 to 10 Mbps. The stations are connected by hubs that allow each station to communicate with every other station in the LAN. There are a number of varieties of classic Ethernet, commonly referred as 10BASE-X. Here, 10 is the maximum throughput, i.e. 10 Mbps, BASE denotes use of baseband transmission, and X is the type of medium used.
The common varieties of classic Ethernet are −
In switched Ethernet, the hub connecting the stations of the classic Ethernet is replaced by a switch. The switch connects the high-speed backplane bus to all the stations in the LAN. The switch-box contains a number of ports, typically within the range of 4 – 48. A station can be connected in the network by simply plugging a connector to any of the ports. Connections from a backbone Ethernet switch can go to computers, peripherals or other Ethernet switches and Ethernet hubs.
Classic Ethernet is simplest form of Ethernet. It comprises of an Ethernet medium composed of a long piece of coaxial cable. Stations can be connected to the coaxial cable using a card called the network interface (NI). The NIs are responsible for receiving and transmitting data through the network. Repeaters are used to make end-to-end joins between cable segments as well as re-generate the signals if they weaken. When a station is ready to transmit, it places its frame in the cable. This arrangement is called the broadcast bus.
The configuration of classic Ethernet is illustrated as follows −
The frames for transmission of both classic Ethernet and switched Ethernet are same except for one field. Both of them have seven fields. The difference between the two is that while classic Ethernet has a ‘Type’ field, switched Ethernet has ‘Length’ field. The fields are −