Techniques include retrieving from storage a plurality of policies for sharing a shared channel among nodes in a data communications network. The plurality of polices define a tree of periodic schedules of variable periods, each policy defines a transmit time slot as a unique slot i of a modulus of a power m of a base b of a series of time slots, where m indicates a level of the tree of periodic schedules. The method also includes; observing at a first node the probabilities of empty time slots, successful time slots, and collision time slots on the shared channel; selecting at the first node a first policy among the plurality of policies based on the probabilities observed instead of a message received from a central authority; and transmitting a local data packet from the first node onto the shared channel at a transmit time based on the first policy.