ENGINEERING ASPECTS FOR TOKEN-RING DESIGN.

Abstract

Some of the design criteria chosen for selecting a synchronous token ring as the major approach for a baseband LAN effort at the IBM Zurich Research Laboratory are given. This effort has resulted in an enhanced token-ring architecture, with priorities, a robust recovery mechanism and a two-level wiring hierarchy with distribution panels. The key parameters for synchronous transmission using phase-locked loops for clock extraction are given. Special emphasis is placed on the synchronization method and on the parameters and tolerances of the receiver that limit distance and number of stations that can be attached reliably to a single ring. Theoretical and experimental results for a chain of repeaters are presented, and worst-case design criteria for synchronization and low error rate are given.