Frame removal mechanism for token ring networks using one or more start

Abstract

Frame processing apparatus, and a related method for its operation, for use in a station connected to a token ring network, to ensure rapid stripping of frames from the network without reference to source addresses in the frames, and in spite of the possible presence of extraneous no-owner frames on the network. The adverse effects of extraneous no-owner frames are avoided by any of three techniques. First, transmitted information frames are preceded by a start strip delimiter frame and followed by an end strip delimiter frame. The process strips all incoming frames (except tokens and ring initialization frames, which are specially handled), but does not count the stripped frames until the start strip delimiter frame is detected. Therefore, extraneous frames preceding the transmitted information frames will be stripped but not counted, and all of the transmitted frames will be stripped. In another approach, an estimated stripping time is used to terminate stripping. Frame counters are not then needed and extraneous frames will be stripped prior to the desired information frames. A third approach is to preset the transmitted frame count to some selected value, so that more frames will be stripped than were transmitted. Thus, preceding extraneous frames will be stripped, but the end strip delimiter will still terminate stripping and preclude overstripping.