Amortized efficiency of list update and paging rules
Communications of the ACM
On the competitiveness of on-line real-time task scheduling
Real-Time Systems
High-speed switch scheduling for local-area networks
ACM Transactions on Computer Systems (TOCS)
Dover: An Optimal On-Line Scheduling Algorithm for Overloaded Uniprocessor Real-Time Systems
SIAM Journal on Computing
Scheduling algorithms for input-queued cell switches
Scheduling algorithms for input-queued cell switches
Heuristics for Scheduling I/O Operations
IEEE Transactions on Parallel and Distributed Systems
Online computation and competitive analysis
Online computation and competitive analysis
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Non-Preemptive Real-Time Scheduling of Multimedia Tasks
Real-Time Systems
Online scheduling with hard deadlines
Journal of Algorithms
Bounded latency scheduling scheme for ATM cells
Computer Networks: The International Journal of Computer and Telecommunications Networking
Buffer overflow management in QoS switches
STOC '01 Proceedings of the thirty-third annual ACM symposium on Theory of computing
A unified approach to approximating resource allocation and scheduling
Journal of the ACM (JACM)
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Competitive queueing policies for QoS switches
SODA '03 Proceedings of the fourteenth annual ACM-SIAM symposium on Discrete algorithms
Packet-mode emulation of output-queued switches
Proceedings of the eighteenth annual ACM symposium on Parallelism in algorithms and architectures
Packet mode and QoS algorithms for buffered crossbar switches with FIFO queuing
Proceedings of the twenty-seventh ACM symposium on Principles of distributed computing
Improved upper bounds on the competitive ratio for online realtime scheduling
ESA'07 Proceedings of the 15th annual European conference on Algorithms
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This paper considers the problem of packet-mode scheduling of input queued switches. Packets have variable lengths, and are divided into cells of unit length. Each packet arrives to the switch with a given deadline by which it must traverse the switch. A packet successfully passes the switch if the sequence of cells comprising it is contiguously transmitted out of the switch before the packet's deadline expires. A packet transmission may be preempted and restarted from the beginning later. The scheduling policy has to decide at each time step which packets to serve. The problem is online in nature, and thus we use competitive analysis to measure the performance of our scheduling policies.First we consider the case where the goal of the switch policy is to maximize the total number of successfully transmitted packets. We derive two algorithms achieving the competitive ratios of (22√log L +1) and N+ 1, respectively, where L is the ratio between the longest and the shortest packet lengths and N is the number of input/output ports. We also show that any deterministic online algorithm has a competitive ratio of at least (⌊log L⌋ + 1, N).Then we study the general case in which each packet has an intrinsic value representing its priority, and the goal is to maximize the total value of successfully transmitted packets. We derive an algorithm which achieves a competitive ratio of 2κ+2√κ+1/2+ (2κ+√κ+1/2+1) (√κ+1/2+3), where κ is the ratio between the maximum and the minimum value per cell. We note that [4] gives a lower bound of Ω(κ) on the performance of any deterministic online algorithm. In particular, our algorithm achieves a competitive ratio of approximately 11.123 for κ=1, which improves upon the previous best-known upper bound for this problem [17].We complement our results by studying the offline version of the problem, which is NP-hard We give a pseudo-polynomial 3-approximation algorithm for the general case and a polynomial 3-approximation algorithm for the case of unit value packets.