The IBM token-ring network — A functional overview

The IBM token-ring network, which is based on a ring topology with token-access control, is described. In particular, a star-wired ring topology and the functions of several of the key physical components that compromise a token-ring network are examined. The token-access control protocol for regulating data flow on the ring is explained, including the data frame format and addressing structures, mechanisms for ensuring token integrity and fair token access to all attached nodes, and some token-ring performance attributes. The relationship between the token-ring architecture and systems network architecture (SNA) is also discussed. Some of the fault detection and isolation capabilities that are available with the token-ring LAN are also presented.