Switching hub, a ring network system, and, the route switching method for a ring network system

摘要

PROBLEM TO BE SOLVED: To provide a switching hub with which frame loss is reduced at the time of route switching in a ring network system, and a ring network system and a route switch method for a ring network system.;SOLUTION: The switching hub includes: a ring monitoring section 38 and a CPU 24 for obtaining information on an open/close state of a ring transmission path; a ring management tag providing section 40 for assigning, to a communication frame entering from outside of the ring transmission path as a ring management tag, a first tag when the ring transmission path is in the close state and a second tag when the ring transmission path is in the open state as indicated by the information; a ring management tag removal section 41 for removing the ring management tag from a communication frame exiting the ring transmission path; and a retrieval section 36 for restricting the passage of a communication frame that is about to flow on the ring transmission path depending on whether its ring management tag is the first tag or the second tag.;COPYRIGHT: (C)2012,JPO&INPIT