This paper describes a new token-based medium access protocol for real-time networks and its implementation on a wireless network. Originally, the protocol is developed for use in low cost domestic or home networks that are based on Ethernet hardware. In contrast to existing protocols the token is assigned to network nodes on basis of a pre-emptive earliest deadline first (PEDF) schedule of the multimedia streams. The scheduler is distributed over all active nodes in the network. Although other schedulers could be used, PEDF is chosen because it has a theoretical bandwidth utilization of one hundred percent and feasibility analysis is very simple, so even simple devices can participate in such a network. This is confirmed by simulation experiments and a prototype based on Ethernet hardware. The protocol is successfully adapted to and implemented on an IEEE 802.11b wireless LAN, even though this type of network has some unpredictable properties, such as bandwidth switching.
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