TORNET: A local area network

TORNET is an experimental local area computer network presently being designed and built in the Computer Group Laboratory of the Department of Electrical Engineering at the University of Toronto. The network consists of a number of local rings, each attached to a central ring. The local rings employ a variation on the slotted-ring format that uses a limited insertion technique to achieve reasonable response times for character traffic among many devices and small computers. Two fixed-length packet formats (one byte or 128 bytes of data) are used on the local rings. Only the longer format is used on the central ring which generally provides record level access to shared specialized equipment. The main objective in the local ring design is a low-cost port for inexpensive terminals, sensors, etc. The paper concentrates on the functional characteristics of the local rings, including delay-throughput comparisons with other well-known ring schemes.