Problem description:

What is a token network?

Analysis:

The access control of token ring network is realized by token. Usually the token always flows on the ring. When a station has data to send, the flag bit of the token must be converted into the flag bit of a data frame, which is called interception. Then, the data in the sending buffer is sent out from the "outbound into the ring" end of the repeater. In order for the transmitting station to insert the transmitted data into the ring, the input and output terminals of the repeater are disconnected, and the transmitted data is transmitted as follows. From the "outbound ring" end of the repeater to the inbound end of the next repeater, it travels along the ring and finally returns to the sending station. The information returned to the sending station can be temporarily stored or deleted by the sending station and must be removed from the ring. That is, the repeater can't connect until all the information is returned to the source site, otherwise, the information will be sent to the ring again.

When the transponder is transmitting, the token has been intercepted by it, and there is no token on the ring. All other stations can't send data, but just forward the received bit stream intact. At this time, only one station in the whole ring is working in the transmission mode, and all other stations are listening. It is not allowed to send at the same time, otherwise an unexpected conflict will occur.

When the sent data frame bypasses the ring, it will return to the site where the data was sent. By checking the returned data frame, we can know whether the transmission is correct or not. At the same time, once the last bit of the transmitted data frame returns to the original station, the original station must immediately copy a token and send it to the ring. Then the repeater of the station began to listen.

When there are many stations on the ring, even if only two stations are communicating, there will still be considerable delay. This is a prominent shortcoming of the ring network. Secondly, the token management of token cup network is more complicated. The third disadvantage of token ring network is that if one station fails, it will lead to the failure of the whole network. The common solution is to automatically shunt the fault points with electronic switches.

The biggest advantage of token ring network is that it can work efficiently under heavy load. The whole ring network will not have several stations competing for transmission media at the same time, so the efficiency will not be reduced due to collision. Another advantage of Token Ring Network is that each repeater is equivalent to an active network interface, which shapes the received bit stream before sending it out, so the signal strength will not be weakened by transmission, and long-distance transmission can be carried out if the transmission delay allows.