An architecture and implementation for an FDDI MAC concentrator

The authors present an architecture and implementation for an FDDI (Fiber Distributed Data Interface) concentrator with media access control (MAC) sublayer support. The architecture calls for a distributed implementation of the SMT CMT (station management connection management) for the concentrator. The main features include microcontroller-based physical connection management configuration management, and link error monitor for the back-end and front-end PHYs. Other features include a node-processor-based entity coordination management, ring management, MAC support, SMT frame transaction support, and link layer control. Communication, between the node processor and the peripheral microcontrollers is two-way serial for high-speed support of concentrator management transactions between the physical entities and the node processor. The architecture is modular because the microcontroller-based management allows for local intelligence for a group of back-end physical entities.