How and why IBM pioneered the development of token ring in the early 1980s as a highly robust and efficient network protocol for mission-critical business applications is now considered ancient history. Nevertheless the underlying customer requirements that drove the development effort have never been more pressing than in the Internet era. Token ring technology has served that business well, becoming one of the two major LAN types and enjoying widespread industry acceptance.
Token ring is an indispensable foundation in many corporate infrastructures.
Each station maintains a record of its nearest active upstream neighbor's address, and of the number of frames it received that were corrupted after being transmitted by its upstream neighbor. If the number of corrupted frames exceeds a settable threshold, messages are transmitted that can be used by network management to locate a problematic station. In the event of hard errors caused by stations malfunctioning, special frames are transmitted that will automatically cause the failing station to remove itself from the ring, allowing the ring to heal. No advantage accrues based on topological position in the ring. Source-route bridging allows for multiple bridges and parallel bridges, improving network reliability and availability, and significantly improving performance.