No-owner frame and multiple token removal mechanism for token ring networks

摘要

A ring purging station for a token-ring network is disclosed. The station performs purging operations to remove no-owner frames and frame remnants from the network. The station begins a purging operation by detecting the token on the network and removing it. The station then begins stripping all frames and remnants of frames that it receives from the network, and transits one or more purge marker frames. When the station detects one of the one or more purge marker frames it transmitted, it ends the purging operation, and releases the token back onto the ring. In this way no-owner frames and frame fragments are removed from the network, while the ring is otherwise normally operating. In an embodiment of the invention, a sequence number is associated with each purging operation, included in the purge marker frame(s), and verified upon receipt of the purge marker frame(s). The station also corrects multiple token conditions when a multiple token condition is detected during a purging operation. A further aspect of the invention is an election method for selecting a purging station from the stations on the ring.