Abstract: Techniques for using a shared channel in data communications networks include observing at a local node, during a frame of multiple transmission slots, packets transmitted. Based on the packets, a node identifier and transmission slot are determined for each node in a contention set. A priority for each node in the contention set is determined based on the identifier. When the local node is new to the shared channel, a transmission key is determined for the local node, which indicates a subset of transmission slots in the frame based on the identifier for the local node. When the local node is still new, it transmits a packet only when a current transmission slot is indicated by the transmission key. If not new and with carrier sensing, transmission is delayed even when the priority for the local node in the current time slot is greater than any other.