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Token Passing

In the access method known as token passing, a special type of packet, called a token, circulates around a cable ring from computer to computer. When any computer on the ring needs to send data across the network, it must wait for a free token. When a free token is detected, the computer will take control of it if the computer has data to send.

The computer can now transmit data. Data is transmitted in frames, and additional information, such as addressing, is attached to the frame in the form of headers and trailers. Let's talk more about these later. For now, only the computer that has the token can transmit on the network.

While the token is in use by this one computer other computers cannot send data. Because only one computer at a time can use the token, no contention and no collision take place, and no time is spent waiting for computers to resend tokens due to network traffic on the cable.

Next: Access Method Summary