Achieving realtime capabilities in ethernet networks by edge-coloring of communication conflict-multigraphs
Frank Dopatka, Roland Wismüller · International Conference on Parallel and Distributed Computing and Networks · 2006
This paper presents a top-down Quality-of-Service (QoS) approach to design realtime Ethernet networks for automation systems based upon tree topologies. Therefore, the parallelism of switched unicast communication is utilized by generating an off-line schedule, which considers each port of a switch as an exclusive networking resource. We point out that the schedule can be generated independently for each switch. Starting from a given network infrastructure and QoS-requests, we present a method consisting of attribution to identify routes, specification of conflicts inside the switches, and building of a conflict-multigraph for each switch. The schedule is realized using greedy edge-coloring of the graph together with optional edge pre-sorting and re-coloring after execution of the greedy-algorithm. The method is shown for a class of special cases with unitary packet-sizes and transmission of every request in each cycle-period. Finally, some first results of this method are presented.