In this paper, we have proposed a new method for deriving end-to-end delay bounds for connections in tandem network, which uses a FIFO scheduling discipline. Our new method takes into account delay dependencies in successive servers along the path of a connection, which is in general very difficult for delay analysis, and achieves better performance than the method provided in [8, 9]. This can be observed through the extensive simulation experiments provided in previous section.
When servers do not have traffic regulation mechanisms (as is the fact with all work conserving servers), circular dependencies amond connections introduce feedback effects on local delays, which in turn show up as non-linearities in the local delay calculations. For this reason, the analysis method described in this paper is limited to sets of connections that do not generate cycles in the network. Based on our previous work on decomposition-based analysis with feedback effects of networks with both FIFO and static-priority servers ([23]), we currently working on extending the approach proposed in this paper to general networks.
Although the integrated approach for analyzing pairs of servers presented in this paper is generic in principle, we derived the closed form delay formulas for the FIFO service discipline (in Theorem 1). We are currently extending the applicability of this approach to the static-priority discipline by deriving the appropriate closed form solutions of the delay formulas.
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