Complexity of Minimum Length Scheduling for Precedence Constrained Messages in Distributed Systems
IEEE Transactions on Parallel and Distributed Systems
Scheduling of real-time messages in optical broadcast-and-select networks
IEEE/ACM Transactions on Networking (TON)
INFOCOM '97 Proceedings of the INFOCOM '97. Sixteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Driving the Information Revolution
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We devise a preallocation based single hop wavelength division multiple access (WDMA) scheme to support time constrained communication in star coupled optical networks. We consider a star coupled broadcast and select network architecture in which N stations are connected to a star coupler with W different wavelength channels. Each of the W wavelength channels is slotted and shared by the N stations by means of time division multiplexing. Networks with different transceiver configurations, i.e., TT-FR, FT-TR, and TT-TR systems, are investigated. We characterize each real time message stream M, with two parameters, relative message deadline D/sub i/ and maximum (total) message size C/sub i/ that can arrive within any time interval of length D/sub i/. We then discuss a restricted case in a TT-FR system in which the message streams from a source station are assumed to be all going to the same destination station. Under this assumption, no source/destination conflicts may occur. We propose a preallocation based slot assignment scheme to allocate slots to a set of isochronous message streams, {M/sub i/=(C/sub i/, D/sub i/))|1/spl les/i/spl les/n}, so that in any time window of size D/sub i/ slots, at least C/sub i/ slots on a wavelength channel are allocated to M/sub i/ for all i. With the solution derived in the restricted case as a basis, we then consider slot assignment in a (general) TT-TR system, and propose a binary splitting scheme to assign each message stream sufficient and well spaced slots to fulfill its timing requirement, subject to source/destination conflict constraints. We rigorously prove the invariant properties and the correctness of the binary splitting scheme.