Token Ring monitor

The Token Ring monitor takes over the monitoring of the protocol flow in the Token Ring. Each ring has exactly one station that assumes the function of an active monitor.

Since each ring station can be active ring monitor at any time, one station is determined by a fixed procedure, the so-called token claiming. All other active ring stations are in standby mode with respect to the monitor function.

The monitor station monitors the protocol traffic on the ring and determines, among other things, faulty or incomplete tokens, frames and priority tokens circling the ring several times and checks whether there are several active monitors or several tokens in the ring. The monitor ensures the minimum storage capacity of a ring of three bytes and controls the clock. In case of an error, the monitor empties the ring by sending a broadcast frame to all active stations and generating a new token.