Detection of No Monitor Condition by Standby Monitors
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
This article describes a mechanism for use in a local area network by which a standby monitor can detect both the absence and failure of an active monitor. A token ring consists of a group of monitors, computers, or terminals that can pass messages to each one, in turn, by means of a circulating signal ("token"). Only one message is permitted on the ring at one time. The token is used by each station to determine the point in time that it can transmit without interfering with another message. One monitor is required to supervise the action of the "token." On each ring one ring station, the active monitor, performs token supervision. All other stations on the ring capable of performing token supervision are designated standby monitors.