LAN Communication
Ethernet is implemented using the bus topology and uses a system known as Carrier Sense Multiple Access with Collision Detection (CSMA/CD) to control network communication. The bus topology allows the connection of more than one computer to the cable. The NIC listens to the cable for a quiet period during which it can send messages and detects whether messages have collided in transit. In such an event, neither message will arrive at its destination and both will be retransmitted. Ethernet transmits data at 10 Mbps. Fast Ethernet works on the same principles as Ethernet but operates at 100 Mbps.
A token ring network transmits data by passing a "token" around the network. If the token is free of data, a computer waiting to send data grabs it, attaches the data and the electronic address to the token, and sends it on its way. When the token reaches its destination computer, the data is removed and the token is sent on. Token rings transmit data at 4 or 16 Mbps.