Ethernet Protocol
The Ethernet protocol is the most widely used.
Ethernet uses a system where each computer listens to the cable before sending
anything through the network. This is called Carrier Sense Multiple
Access/Collision Detection (CSMA/CD). If the network is clear, the computer
will transmit, or send, the data. If any device attached to a network, such as file
servers, printers, or workstations (all of which are called nodes), is
already being used and is sending data on the cable, the computer will wait and try again
when the line is clear.
Schematic of an Ethernet network
Sometimes, two computers attempt to send
things at the same instant. When this happens, a collision occurs. Each computer then
backs off and waits some time before attempting to transmit again. With this type of
method, it is normal to have collisions. However, the delay that is caused by collisions
and re-transmitting is very small and does not normally effect the speed of data that is
sent on the network. The Ethernet protocol allows for Bus or Star topologies.
Collisions on an Ethernet
