Abstract: A contention mechanism is disclosed for a communication network that provides perfect scheduling to avoid collisions between packets from a cluster of M circuit boards connected to a communications bus. The contention mechanism includes a 2-phase contention procedure comprising a first phase priority contention phase, where boards with a highest priority and a real data packet to transmit proceed into a second contention phase, where a pointer is used to declare one of the remaining priority phase circuit boards as the overall winner to transmit its packet during a subsequent packet period. When no circuit board has a packet to transmit, all M circuit boards are declared as winners of the first priority phase, and a board is declared the winner on a distributed basis to transmit a "dead-space" packet over the bus.