Patent ID: 7912081

Claim:
A method of medium access on a distributed communications network, wherein communication activities on the distributed communications network take place during communications windows, wherein a given communications window comprises a plurality of timeslots and a scheduling window that comprises a subset of the plurality of timeslots, the method comprising: a network device transmitting a beacon to other network devices on the distributed communications network during a first scheduling window of a first communications window, wherein the beacon comprises a reservation of timeslots during a second communications window, and wherein the beacon further comprises an indication of whether the reservation of timeslots conforms with a predetermined timeslot reservation protocol shared among the network devices on the distributed communications network; and the network device modifying its reservation of timeslots such that its reservation does not conflict with the other network device's reservation when the beacon indicates that the reservation of timeslots does not conform with the predetermined timeslot reservation protocol and the network device receives a preemption request from another network device on the distributed communications network indicating that the network device's reservation conflicts with the other network device's reservation of timeslots during the second communications window; wherein the plurality of timeslots of the given communications window are arranged into a plurality of groups of contiguous timeslots, each group of the plurality having an equal number of timeslots; wherein the predetermined timeslot reservation protocol allows network devices to make horizontal reservations and vertical reservations, a horizontal reservation comprising a reservation of a timeslot at a specific slot location from each group of contiguous timeslots of the plurality of groups, and a vertical reservation comprising a reservation of a plurality of contiguous timeslots within a group of contiguous timeslots of the plurality of contiguous timeslots; wherein the predetermined timeslot reservation protocol maintains a portion of the plurality of timeslots for horizontal reservations; and wherein the reservation of timeslots that does not conform with the predetermined timeslot reservation protocol comprises a vertical reservation within the portion of the plurality of timeslots for horizontal reservations.