In token ring network, RPU (Repeater) obtains every bit signal in the frame from one ring segment (called "uplink"), regenerates it (shapes and amplifies it), and forwards it to another ring segment (called "downlink"). If the destination address in the frame is consistent with the address of this node, copy the MAC frame and send it to the node attached to this RPU. In this network, MAC frames will be constantly regenerated and forwarded in the loop, which is completed by the sending node. There is a special loop monitor to monitor and maintain the loop. RPU is responsible for network segment connection, information replication, regeneration and forwarding, ring network monitoring, etc. Once the RPU fails, the network will be paralyzed.
In token ring network, only devices with tokens are allowed to transmit data in the network. This ensures that only one device in the network can transmit information at a time. In the ring network, the information flow can only be one-way, and each station receiving the packet forwards the packet to its downstream station. The data packet is transmitted once in the ring network and finally recovered by the sending station. When the data packet passes through the destination station, the destination station judges that it is the receiving station according to the destination address in the data packet, and copies the information to its receiving buffer. The transmission medium on the loop is common to all computers, and a computer must pass through all interfaces of the loop when sending information. Only when the destination address of the transmitted information is consistent with the address of a computer on the loop, will it be accepted by the ring interface of the computer, otherwise, the information will be transmitted to the ring interface of the next computer.
The above is the way to receive data. In terms of data transmission, in this network, a special packet called token usually circulates on the ring. Only the station that obtained the token can send the message. When a station sends a message, it will send the token down so that the downstream station can get the opportunity to send the message. The access control of ring network is generally decentralized management, and the ring network itself is a ring in physics, so token ring access control method is suitable. Sometimes it is centralized management. At this time, there must be special equipment responsible for access control management. However, every computer in the ring network must pass through all ring interfaces when sending information. If a ring interface program fails, the whole network will be paralyzed, so the requirements for ring interfaces are higher. In order to improve the reliability, when an interface fails, a ring bypass method is adopted.