Method and system for real-time change of slot duration

Abstract

A supervisory communications device, such as a headend device within a cable communications network, monitors and controls communications with a plurality of remote communications devices, such as cable modems, throughout a widely distributed network, including the Internet. The supervisory device establishes the upstream slot structure and allocates upstream bandwidth by sending UCD and MAP messages over its downstream channel. The supervisory device also uses the MAP messages and minislot counts to anticipate bursts from the remote devices. Dual registers are provided within the supervisory device to generate minislot counts. A primary register generates minislot counts for a current slot structure, and a secondary register generates minislot counts for a revised slot structure. Software executed on the supervisory device determines a switchover time for changing to the revised slot structure and revised minislot count. Prior to switchover, the revised minislot count is passed to the current slot structure processor allowing it to anticipate bursts from the remote devices using the revised slot structure. At switchover, the supervisory device also switches the revised clock along with the revised slot structure, deactivates the primary register, and switches to the secondary register to provide a seamless transition in real time.