Cascading twisted pair ethernet hubs by designating one hub as a master and designating all other hubs as slaves

摘要

A hub in a star local area network (LAN) in which a number of slave hubs are connected to a master hub. A number of slave stations are connected to each slave hub. A SREQ link and a MACK link connect the master hub and the slave hubs. A slave local preferred station is selected at the slave hub from among ones of the slave stations that attempt to transmit a frame simultaneously. The slave transmits a slave local preferred station frame over the SREQ link. A master preferred station is selected at the master hub from among the slave local preferred station frame and ones of the plurality of master local stations that attempt to transmit a frame simultaneously. A small FIFO at each hub is provided to maintain collision resolution. Upon a condition that a master preferred station ID and a slave local preferred station ID are not identical, the slave hub flushes its small FIFO and adds the local preferred station to its local non-preferred station list. Then, the slave hub stores the master preferred station frame (MACK frame) in the small FIFO. In parallel, the slave hub transmits the MACK frame to its local stations. Upon a condition that the master preferred station ID and the slave local preferred station ID are identical the slave hub continues to transmit its local preferred station frame to the master hub over the SREQn link and, in parallel, continues to store it in the slave hub small FIFO. An improved fairness and deterministic precedence algorithm ensures that a station which is in backoff and does not attempt to link does not lose its priority with reference to other transmitting stations.