Is the DQDB priority mechanism good enough for the network intended real-time applications?
Rodrigo Santos, M. Zambón, Jorge Almeida Santos, Javier Orozco · 2002
A survey of previous research on the subject of DQDB real-time schedulability shows that its protocol is not coherent with the Fair Round Robin or the Rate Monotonic priority disciplines. In order to make it coherent, major modifications to the standard are necessary. Instead of following that approach, the real-time schedulability condition is formally proved strictly adhering to the letter of the standard as it stands today. Schedulability depends heavily on the utilization factors which, in turn, depend on the position of the station on the buses. They have upper bounds compatible with intended applications.