Priority-based arbitrator on a token-based communication medium

摘要

This invention is an arbitration scheme for a token-based communications medium which is intended for use when there are timing deadlines for transactions on the medium. Initially knowledge of the expected workload is used to determine for each module its priority as well as the limit on the duration of time lower priority modules can be permitted to use the medium between request and completion of a transaction for this module. A count is maintained for each module of the number of data units that has been transferred on the medium by lower priority modules since the time this module last requested the medium. A module can transmit a selected number of data units if it has the token and the count of none of its higher priority modules has reached a corresponding limit.