Switched token ring over ISL (TR-ISL) network

摘要

A technique efficiently transports token ring (TR) frames over trunks interconnecting switches of a distributed TR bridge. The TR bridge is characterized by a logical switch fabric that is distributed among the interconnected switches by the trunks, which are preferably interswitch link (ISL) trunks. Each switch includes a Bridge Relay Function (BRF) coupled to a plurality of Concentrator Relay Functions (CRFs) having a plurality of ports for receiving TR frames over TR segments. The BRF and CRF of the distributed TR bridge operate according to a 2-tier switching model wherein each CRF and BRF is assigned an individual virtual local area network identifier. The technique encapsulates the TR frames in a TR-ISL protocol format that accomodates differences in formats of various TR frames and that comports with the 2-tier switching model of the distributed TR bridge.