In this paper we have summarised recent advances made in the area of real-time MAC protocols such as 802.3D, 802.4, 802.5 and FDDI. We introduced the problems that are tackled by current research - shedul-ing message transmissions in a fault free environment or in cases when single failures can occur - and summarised the results for each of these protocols. We presented a comparison of the above protocols from a number of different viewpoints and showed that the 802.3D protocol was interesting for many reasons except for the size of the network which is limited for intrinsic reasons and for transmission speed which requires to reduce the size of the network. For soft realtime applications, existing studies are not satisfactory in the sense that they evaluate average delays without studying the variance or the proportion of messages that miss their deadline and by how much.
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