Novel real-time applications require highperformance real-time distributed systems, and therefore high-performance real-time networks. We examine a Hard Real-Time Distributed Multiaccess problem which arises with such application problems. We present a solution, based on broadcast LANs or busses, such as Gigabit Ethernets or busses internal to ATM nodes, associated with a deterministic Ethernetlike protocol called CSMA Deadline Driven Collision Resolution. We give an analysis of balanced m-ary tree algorithms which are used by CSMA DDCR, and derive feasibility conditions for the HRTDM problem.