Abstract: A communication protocol includes a hierarchical arrangement of time slots within a communication channel for transmission and reception of isochronous data (e.g., video, audio, etc.) between components of a computer network. One of the time slots may include a window for transmission of keyboard and/or cursor control data from a client unit to a server, for example as a series of past and present keyboard and/or cursor control entries, with these entries being accompanied by a counter value indicative of the number of new entries since a previous transmission. Audio rate control information may also be transmitted from the client unit to the server during the reverse time slot and may be used by the server to determine the amount of audio information to be transmitted to the client unit in a subsequent forward time slot transmission period. The audio rate control information is determined according to the amount of stored audio information at the client unit.