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Backbone Networks (backbone + network)
Selected AbstractsA new traffic model for backbone networks and its application to performance analysisINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2008Ming Yu Abstract In this paper, we present a new traffic model constructed from a random number of shifting level processes (SLP) aggregated over time, in which the lengths of the active periods of the SLP are of Pareto or truncated Pareto distribution. For both cases, the model has been proved to be asymptotically second-order self-similar. However, based on extensive traffic data we collected from a backbone network, we find that the active periods of the constructing SLPs can be approximated better by a truncated Pareto distribution, instead of the Pareto distribution as assumed in existing traffic model constructions. The queueing problem of a single server fed with a traffic described by the model is equivalently converted to a problem with a traffic described by Norros' model. For the tail probability of the queue length distribution, an approximate expression and upper bound have been found in terms of large deviation estimates and are mathematically more tractable than existing results. The effectiveness of the traffic model and performance results are demonstrated by our simulations and experimental studies on a backbone network. Copyright © 2007 John Wiley & Sons, Ltd. [source] Hierarchical VP restoration management system for a reliable ATM backbone networkINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2002Won-Kyu Hong This paper proposes a distributed ATM VP PVC restoration framework with the dynamic rerouting schemes in a hierarchical transport network. The rerouting algorithm aims to provide rapid ATM VP PVC restoration in the case of fault or performance degradation in terms of maximization of network resource utilization and satisfaction of the end user's QoS requirement. Copyright © 2002 John Wiley & Sons, Ltd. [source] A GRASP with path-relinking for private virtual circuit routing,NETWORKS: AN INTERNATIONAL JOURNAL, Issue 2 2003Mauricio G. C. Resende Abstract A frame relay service offers virtual private networks to customers by provisioning a set of long-term private virtual circuits (PVCs) between customer endpoints on a large backbone network. During the provisioning of a PVC, routing decisions are made without any knowledge of future requests. Over time, these decisions can cause inefficiencies in the network and occasional offline rerouting of the PVCs is needed. In this paper, the offline PVC routing problem is formulated as an integer multicommodity flow problem with additional constraints and with an objective function that minimizes propagation delays and/or network congestion. We propose variants of a GRASP with path-relinking heuristic for this problem. Experimental results for realistic-size problems are reported, showing that the proposed heuristics are able to improve the solutions found with standard routing techniques. Moreover, the structure of our objective function provides a useful strategy for setting the appropriate value of its weight parameter, to achieve some quality of service (QoS) level defined by a desired balance between propagation delay and delay due to network congestion. © 2003 Wiley Periodicals, Inc. [source] A new traffic model for backbone networks and its application to performance analysisINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2008Ming Yu Abstract In this paper, we present a new traffic model constructed from a random number of shifting level processes (SLP) aggregated over time, in which the lengths of the active periods of the SLP are of Pareto or truncated Pareto distribution. For both cases, the model has been proved to be asymptotically second-order self-similar. However, based on extensive traffic data we collected from a backbone network, we find that the active periods of the constructing SLPs can be approximated better by a truncated Pareto distribution, instead of the Pareto distribution as assumed in existing traffic model constructions. The queueing problem of a single server fed with a traffic described by the model is equivalently converted to a problem with a traffic described by Norros' model. For the tail probability of the queue length distribution, an approximate expression and upper bound have been found in terms of large deviation estimates and are mathematically more tractable than existing results. The effectiveness of the traffic model and performance results are demonstrated by our simulations and experimental studies on a backbone network. Copyright © 2007 John Wiley & Sons, Ltd. [source] A network-centric approach for access and interface selection in heterogeneous wireless environmentsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2008George Koundourakis Abstract In this paper, we introduce a network-based approach for access and interface selection (AIS) in the context of resource management in heterogeneous wireless environments (UMTS, WLAN and DVB-T). We focus on the optimization of resource utilization, while ensuring acceptable quality of service (QoS) provision to the end users. Our objective is to optimally manage the overall system resources and minimize the possibility of QoS handovers (non-mobility handovers). The adopted architecture applies to typical heterogeneous environments and network entities (Access Routers) are enhanced with extra functionalities. We propose an AIS algorithm that exploits the multihoming concept and globally manages network resources at both radio access and IP backbone networks. The algorithm can estimate near-optimal solutions in real time and we also introduce a novel triggering policy. We present simulation results of typical scenarios that demonstrate the advantages of our approach. System performance metrics, derived from the simulations, show minimum degradations in high load and congestion situations. Copyright © 2007 John Wiley & Sons, Ltd. [source] QoS experiences in native IPv6 networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2009Athanassios Liakopoulos Deployment of IPv6 technology in research and commercial networks has accelerated in the last few years. Inevitably, as more advanced services take advantage of the new technology, IPv6 traffic gradually increases. Today, there is limited experience in the deployment of Quality of Service (QoS) for IPv6 traffic in backbone networks that support the Differentiated Services framework. As available software and hardware are designed to handle IPv4 packets, there is a need to accurately measure and validate performance of QoS mechanisms in an IPv6 environment. This paper discusses tests and technical challenges in the deployment of IPv6 QoS in core networks, namely the production dual stack gigabit-speed Greek Research and Education Network (GRNET) and the IPv6-only 6NET European test network, using both hardware and software platforms. In either case, we succeeded in delivering advanced transport services to IPv6 traffic and provided different performance guarantees to portions of traffic. The deployed QoS schema was common to IPv6 and IPv4; in most cases both v4 and v6 traffic exhibited comparable performance per class, while imposing no significantly different overhead on network elements. A major conclusion of our tests is that the IPv6 QoS mechanisms are efficiently supported with state-of-the-art router cards at gigabit speeds. Copyright © 2008 John Wiley & Sons, Ltd. [source] A tutorial on using genetic algorithms for the design of network topologyINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2006Bassam Al-Bassam The design of network topology is an important part of network design, since network topology is directly associated with network operational behavior, capacity, reliability, and cost. This paper is a tutorial paper concerned with illustrating how the optimization capabilities of genetic algorithms can be used to design suitable network topologies considering basic topology problems. Simple genetic algorithms have been developed for the topology problem of mesh networks, considering single node and single link failure tolerance. The algorithms are based on criteria of two important measures: minimizing the length of communication links; and minimizing traffic flow through these links for given traffic loads. The first measure contributes to minimizing the cost of cabling, while the second measure contributes to minimizing the cost of link capacity. The work provides a useful approach and tools to network students and professionals concerned with the topology design of backbone networks. The developed software is made available on the Internet.,Copyright © 2006 John Wiley & Sons, Ltd. [source] Packet OADMs for the next generation of ring networksBELL LABS TECHNICAL JOURNAL, Issue 4 2010Dominique Chiaroni The deployment of fiber-to-the-home (FTTH) technology in access networks is creating new demands on metropolitan area and backbone networks. The increasing bit rate per user and the simplification of access networks will make the traffic profile more bursty, requiring new flexible techniques at the metropolitan area network. This paper describes a ring network exploiting optical transparency and packet granularity. After a description of the packet optical add/drop multiplexer (POADM)-based network model motivated by specifications derived from expected needs, the paper addresses the advantages of the approach and the feasibility of the concept. © 2010 Alcatel-Lucent. [source] | ||||||||||