Domus is an architecture for distributed Hash Tables (DHTs) tailored to a shared-all cluster environment. Domus DHTs build on a (dynamic) set of cluster nodes;each node may perform routing and/or storage tasks, for on...
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ISBN:
(纸本)9780889866379
Domus is an architecture for distributed Hash Tables (DHTs) tailored to a shared-all cluster environment. Domus DHTs build on a (dynamic) set of cluster nodes;each node may perform routing and/or storage tasks, for one or more DHTs, as a function of the node base (static) resources and of its (dynamic) state. Domus DHTs also benefit from a rich set of user-level attributes and operations. pDomus is a prototype of Domus that creates an environment where to evaluate the architecture concepts and features. In this paper, we present a set of experiments conduced to obtain figures of merit on the scalability of a specific DHT operation, with several lookup methods and storage technologies. The evaluation also involves a comparison with a database and a P2P-oriented DHT platform. The results are promising, and a motivation for further work.
Optical burst switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over DWDM links. Although several QoS schemes have been proposed for OBS networks, how to provid...
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ISBN:
(纸本)9780889866386
Optical burst switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over DWDM links. Although several QoS schemes have been proposed for OBS networks, how to provide QoS at the high speed required by the OBS network is still an open question. In this paper, we propose a novel O(1) runtime Contour-Based Priority (CBP) algorithm which provides complete priority isolation among different priorities. This is the first practical O(1) runtime priority algorithm proposed and it is well-suited to high speed hardware implementation.
The automatic address configuration simplifies the IP configuration task in IPv6 networks. Two protocols have been developed for automatic address configuration: Neighbor Discovery Protocol (NDP) and Dynamic Host Conf...
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ISBN:
(纸本)9780889866386
The automatic address configuration simplifies the IP configuration task in IPv6 networks. Two protocols have been developed for automatic address configuration: Neighbor Discovery Protocol (NDP) and Dynamic Host Configuration Protocol for IPv6 (DHCPv6). However, these protocols create security holes in a network that expose network nodes to various attacks such as redirect and DoS attacks. In this paper, we propose a new hybrid address autoconfiguration to automate address generation and assignment in IPv6 networks. This autoconfiguration will protect network nodes from address misconfiguration and the mentioned attacks, by managing the flow of NDP and DHCPv6 messages.
Dynamic server resource allocation to services on networks, or utility computing, is a powerful technology to provide required computer resources for multiple service providers at low cost. Virtual machine (VM) techno...
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ISBN:
(纸本)9780889866386
Dynamic server resource allocation to services on networks, or utility computing, is a powerful technology to provide required computer resources for multiple service providers at low cost. Virtual machine (VM) technology can be combined with utility computing to further improve server resource utilization. An important technical issue about VM-based utility computing is optimal placement of VMs on physical server nodes, because performance of services may be seriously affected by VM placement. We address this issue by introducing an on-line placement algorithm on the basis of performance influence among services. We have implemented this algorithm and evaluated on a simulated environment. The results have shown that the proposed mechanism can get roughly 25% better score calculated by the placement rules compared with a random placement algorithm.
When a cluster system interconnects processor and I/O nodes through a network, an optimal placement of I/O nodes is critical to improve the overall system performance by reducing its communication latency. In this pap...
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ISBN:
(纸本)9780889866386
When a cluster system interconnects processor and I/O nodes through a network, an optimal placement of I/O nodes is critical to improve the overall system performance by reducing its communication latency. In this paper, we propose an efficient and scalable I/O node placement scheme, called a relaxed quasi-perfect, for torusbased interconnection networks using Lee distance errorcorrecting code. It provides a more general placement than the previous quasi-perfect placement [I]. We also suggest " fault-tolerant scheme using our I/O placement model for " guaranteed performance. Simulation results show that our scheme provides 53% speed-up over the quasi-perfect. Also the fault tolerant scheme provides a graceful slowdown especially until the number of faulty I/O nodes becomes less than half of the initial I/O nodes.
This paper describes the idea of a multi-dimensional bucket index designed for efficient indexing of telemetric readings. This data structure answers spatio-temporal range queries concerning utility usage within user ...
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ISBN:
(纸本)088986568X
This paper describes the idea of a multi-dimensional bucket index designed for efficient indexing of telemetric readings. This data structure answers spatio-temporal range queries concerning utility usage within user selected region and time. It has a capability of adjusting to incoming data and therefore is suitable to process data of highly dynamic nature. A stochastic prediction method is used to estimate utility usage in the near future. The real world implementation employs mobile agent system network which facilitates effective workload balancing of network hosts.
Hierarchical Interconnection networks (HINs) provide a framework for designing networks with reduced cost, minimized message delay, improved network reliability and fault tolerance. In this paper, we present the main ...
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ISBN:
(纸本)9780889866386
Hierarchical Interconnection networks (HINs) provide a framework for designing networks with reduced cost, minimized message delay, improved network reliability and fault tolerance. In this paper, we present the main characteristics of a number of fault tolerant HINs. These include Block Shift networks (BSNs), Hierarchical Cubic networks (HCNs), and the Hyper-Torus Hierarchical Network (HTHN) using fault tolerant building block (FTBB). We provide an overall performance comparison among these networks. The metrics used for comparison are node degree, network diameter, cost, reliability, and fault tolerance. Our analysis shows that as the number of faults exceeds six, the FTBB has a higher probability to recover from those faults as compared to the HCN and HTHN architectures. The fault diameter of the FTBB is also larger than that of each of the other two architectures, particularly if the number of faults is seven or more. The improvement in the fault tolerance and reliability performance of the FTBB is achieved at the expense of a reasonable increase in the number of nodes and links. The paper provides designers of HIM with the insight needed while evaluating the performance of HINs for possible adoption to their application requirements.
An efficient range query processing support is required for distributed Hash Table (DHT)-based P2P networks as consistent hashing destroys the inherent order of numeric keys. In this paper, we present a lightweight an...
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ISBN:
(纸本)9780889866386
An efficient range query processing support is required for distributed Hash Table (DHT)-based P2P networks as consistent hashing destroys the inherent order of numeric keys. In this paper, we present a lightweight and efficient mechanism, called Range Hash Tree (RHT), to support range queries on DHTs. In RHT, key space is partitioned into small ranges such that data items within one range can be stored on one node. To quickly resolve a range query, we introduce a scalable encoding algorithm that can represent the key space partitioning status with a small RHT Signature. Compared to other approaches, RHT provides a bounded query delay, which is independent of the size of range query and the number of matching data items. Our experiments show that RHT works efficiently on both uniform and much skewed data distributions.
A wireless sensor network consists of many energy-autonomous micro-sensors distributed throughout an area of interest. Each node has a limited energy supply and generates information that needs to be communicated to a...
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ISBN:
(纸本)9780889866379
A wireless sensor network consists of many energy-autonomous micro-sensors distributed throughout an area of interest. Each node has a limited energy supply and generates information that needs to be communicated to a sink node. The basic operation in such a network is the systematic gathering and transmission of sensed data to a base station for further processing. During data gathering, sensors have the ability to perform in-network aggregation (fusion) of data packets route to the base station. The lifetime of such a sensor system is the time during which we can gather information from all the sensors to the base station. Given the location of sensors and the base station and the available energy at each sensor, we are interested in finding an efficient manner in which the data should be collected from all the sensors and transmitted to the base station at a given rate, such that system lifetime is maximized. We present an adaptive data aggregation node selection scheme to solve this problem. Our experimental results demonstrate that the proposed protocols significantly outperform previous methods, in terms of energy saving and system lifetime.
Scheduling dependent tasks is one of the most challenging problems in parallel and distributed systems. It is known to be computationally intractable in its general form as well as several restricted cases. An interes...
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ISBN:
(纸本)9780889866379
Scheduling dependent tasks is one of the most challenging problems in parallel and distributed systems. It is known to be computationally intractable in its general form as well as several restricted cases. An interesting application of scheduling is in the area of energy awareness for mobile battery operated devices where minimizing the energy utilized is the most important scheduling policy consideration. A number of heuristics have been developed for this consideration. In this paper, we study the scheduling problem for a particular battery model. In the proposed work, we show how to enhance a well know approach of accounting for the slack generated at runtime due to the difference between WCET (Worst Case Execution Time) and AET (Actual Execution Time). Our solution exploits the fact that even though some tasks become available based on the actual periodicity of a task they are not executed because the run queue is determined by the schedule generated in the offline phase I of the algorithm using the conservative EDF (Earliest Deadline First) algorithm. We peek at the task run-queue to find such tasks to eliminate wastage of the slack generated. Based on the outcome of the conducted experiments, the proposed algorithm outperformed or matched the performance of the 2-Phase dynamic task scheduling algorithm all the time.
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