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An increasing number of high-performance networks provision dedicated channels through circuit switching or MPLS/GMPLS techniques to support large data transfer. The link bandwidths in such networks are typically shared by multiple users through advance reservation, resulting in varying bandwidth availability in future time. Developing efficient scheduling algorithms for advance bandwidth reservation has become a critical task to improve the utilization of network resources and meet the transport requirements of application users. We consider an exhaustive combination of different path and bandwidth constraints and formulate four types of advance bandwidth scheduling problems, with the same objective to minimize the data transfer end time for a given transfer request with a prespecified data size: 1) fixed path with fixed bandwidth (FPFB); 2) fixed path with variable bandwidth (FPVB); 3) variable path with fixed bandwidth (VPFB); and 4) variable path with variable bandwidth (VPVB). For VPFB and VPVB, we further consider two subcases where the path switching delay is negligible or nonnegligible. We propose an optimal algorithm for each of these scheduling problems except for FPVB and VPVB with nonnegligible path switching delay, which are proven to be NP-complete and nonapproximable, and then tackled by heuristics. The performance superiority of these heuristics is verified by extensive experimental results in a large set of simulated networks in comparison to optimal and greedy strategies.

There are an increasing number of high-performance networks that provision dedicated channels through circuit-switching or MPLS/GMPLS techniques to support bulk data transfer in large-scale science or e-commerce applications. These dedicated links are typically shared by multiple users through advance reservations, resulting in varying bandwidth availability in future time periods. Therefore, efficient advance bandwidth reservation algorithms are needed to improve the utilization of network resources and meet the transport requirements of application users. We investigate the bandwidth-oriented path computation problem for two types of data transfer: (i) fixed path with variable bandwidth and (ii) variable path with variable bandwidth to minimize the transfer end time of a given data size. We prove that both problems are NP-complete and propose a heuristic algorithm for each of them. Extensive simulation results illustrate the performance superiority of the proposed heuristics over methods based on greedy strategies.

The significance of high-performance dedicated networks has been well recognized due to the rapidly increasing number of large-scale applications that require high-speed data transfer. Efficient algorithms are needed for path computation and bandwidth scheduling in dedicated networks to improve the utilization of network resources and meet diverse user requests. We consider two periodic bandwidth scheduling problems: multiple data transfer allocation (MDTA) and multiple fixed-slot bandwidth reservation (MFBR), both of which schedule a number of user requests accumulated in a certain period. MDTA is to assign multiple data transfer requests on several pre-specified network paths to minimize the total data transfer end time, while MFBR is to satisfy multiple bandwidth reservation requests, each of which specifies a bandwidth and a time slot. For MDTA, we design an optimal algorithm and provide its correctness proof; for MFBR, we prove it to be NP-complete and propose a heuristic algorithm, Minimal Bandwidth and Distance Product Algorithm (MBDPA). Extensive simulation results illustrate the performance superiority of the proposed MBDPA over a greedy heuristic approach and provide valuable insight into the advantage of periodic bandwidth scheduling over instant bandwidth scheduling.

There are an increasing number of high- performance networks that provision dedicated channels through circuit-switching or MPLS/GMPLS techniques to support large- scale data transfer. The available bandwidths on these dedicated links vary over time and therefore efficient bandwidth scheduling algorithms are needed to improve the utilization of network resources and satisfy diverse user requirements. Based on different path and bandwidth constraints, we formulate four instant scheduling problems for a data transfer request: (i) variable path with variable bandwidth (VPVB), (ii) fixed path with variable bandwidth (FPVB), (iii) variable path with fixed bandwidth (VPFB), and (iv) fixed path with fixed bandwidth (FPFB), with the common objective to minimize transfer end time for a given data size. We design an optimal algorithm for each of these scheduling problems with polynomial- or pseudo- polynomial-time complexity with respect to the network size and total number of time slots in a bandwidth reservation table.

An increasing number of high performance research network testbeds and production networks have the capability of provisioning dedicated channels for high speed data transfer in support of large scale scientific applications. Each dedicated channel in these networks typically consists of one or more physical links that are shared by multiple applications in both time and bandwidth through in advance reservation. The design of efficient bandwidth scheduling algorithms is critical to maximizing the utilization of dedicated network resources and meeting diverse end-to-end transport performance requirements. The topology of a dedicated network is represented by a graph, where each link maintains a list of residual bandwidths specified as segmented constant functions of time. Given a graph with an aggregated time-bandwidth table combining the reservation information on all links, designated source, and destination vertices, and a specified data size, we formulate and investigate five bandwidth scheduling problems to minimize the data transfer end time under different path and bandwidth constraints: (i) variable path with variable bandwidth (VPVB), which computes the widest (highest bandwidth) path in each time slot; (ii) fixed path with variable bandwidth (FPVB), which computes a fixed path with varying bandwidths across different time slots; (iii) variable path with fixed bandwidth (VPFB), which computes one path in each time slot with the same bandwidth; (iv) fixed path with fixed bandwidth (FPFB), which computes a fixed path with a constant bandwidth; and (v) multiple fixed paths with fixed bandwidths (MFPFB), which computes multiple concurrent fixed paths with constant bandwidths. Among these problems, VPVB represents the most flexible scenario where the network resources are fully utilized and the minimal transfer end time is achieved, while FPFB imposes the most stringent transport conditions by fixing both path and bandwidth. We design an optimal algorithm for each of these scheduling problems. VPVB is solved using an extension of the classical Dijkstra's algorithm, and FPVB is solved using Maximum Permutation Algorithm, which tries all possible permutations of throughputs at different time slots to obtain the minimal transfer end time. The algorithm for VPFB, FPFB, and MFPFB are based on Adjacent Time Slots Search, which finds the minimum transfer end time by examining the possibility of data transfer in any number of contiguous time slots. All these algorithms are of polynomial or pseudo polynomial time complexity with respect to the network size and the total number of time slots in a bandwidth reservation table.