Patent ID: 7260609

Claim:
A method for exchanging data between at least two user units connected by a bus system, comprising: assigning a priority to each message containing data sought to be transmitted by the user units; dynamically modifying, during the operation of the bus system, the priority assigned to each message; categorizing each message into one of a plurality of equivalence classes; assigning a priority to each equivalence class, the assigned priority corresponding to a highest priority of any message in that equivalence class; and dynamically modifying, during the operation of the bus system, the priority of at least one particular equivalence class after a message transmission, wherein: the priority is reduced if at least one of: any message of the particular class was the message transmitted, or any message of the particular class could have been the message transmitted; the priority is maintained if no message of the particular class could have been transmitted, independent of the priority of the particular class; and the priority is raised if no message of the particular class could have been transmitted, but at least one message of the particular class could have been transmitted if the particular class had had a higher priority.