Why a ring?

In a world increasingly populated with Ethernets and Ethernet-like nets there nevertheless continues to be a strong interest in rings of active repeaters for local data communication. This paper explores some of the engineering problems involved in designing a ring that has no central control. It then compares one ring design with the Ethernet on several different operational and subtle technical points of design, maintainability, and future prospects. On each of these points the ring possesses important or interesting advantages. At the same time, the most commonly cited advantage of a ring, “deterministic access time,” is shown to be illusory. The paper concludes that the data communication ring is a sound idea that will prove its value on operational rather than theoretical issues.