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Networking, IEEE/ACM Transactions on

Issue 5 • Date Oct. 2008

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  • [Front cover]

    Publication Year: 2008 , Page(s): C1
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  • IEEE/ACM Transactions on Networking publication information

    Publication Year: 2008 , Page(s): C2
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  • On the Feasibility of Dynamic Congestion-Based Pricing in Differentiated Services Networks

    Publication Year: 2008 , Page(s): 1001 - 1014
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (970 KB) |  | HTML iconHTML  

    Differentiated services can ensure that traffic on some codepoints receives higher quality of service (QoS) than traffic on other codepoints, but without additional mechanisms it cannot target any particular QoS. Congestion-based pricing has been suggested as a method to target QoS in other network architectures. Here, we investigate whether congestion-based pricing can be used to control aggregate traffic into each codepoint by motivating users to choose the codepoints appropriate for each application. We first ask what information needs to be exchanged; we assert that both price and QoS information must be available for users to make decisions. We then ask how effective congestion-based pricing in diffServ can be; we find that it is feasible only for networks with sufficiently high bandwidth to guarantee that QoS can be quickly measured. View full abstract»

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  • Centralized and Distributed Algorithms for Routing and Weighted Max-Min Fair Bandwidth Allocation

    Publication Year: 2008 , Page(s): 1015 - 1024
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (868 KB) |  | HTML iconHTML  

    Given a set of demands between pairs of nodes, we examine the traffic engineering problem of flow routing and fair bandwidth allocation where flows can be split to multiple paths (e.g., MPLS tunnels). This paper presents an algorithm for finding an optimal and global per-commodity max-min fair rate vector in a polynomial number of steps. In addition, we present a fast and novel distributed algorithm where each source router can find the routing and the fair rate allocation for its commodities while keeping the locally optimal max-min fair allocation criteria. The distributed algorithm is a fully polynomial epsilon-approximation (FPTAS) algorithm and is based on a primal-dual alternation technique. We implemented these algorithms to demonstrate its correctness, efficiency, and accuracy. View full abstract»

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  • Capacity Management and Equilibrium for Proportional QoS

    Publication Year: 2008 , Page(s): 1025 - 1037
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (421 KB) |  | HTML iconHTML  

    Differentiated services architectures are scalable solutions for providing class-based quality of service (QoS) over packet switched networks. While qualitative attributes of the offered service classes are often well defined, the actual differentiation between classes is left as an open issue. We address here the proportional QoS model, which aims at maintaining pre-defined ratios between the service class delays (or related congestion measures). In particular, we consider capacity assignment among service classes as the means for attaining this design objective. Starting with a detailed analysis for the single hop model, we first obtain the required capacity assignment for fixed flow rates. We then analyze the scheme under a reactive scenario, in which self-optimizing users may choose their service class in response to capacity modifications. We demonstrate the existence and uniqueness of the equilibrium in which the required ratios are maintained, and address the efficient computation of the optimal capacities. We further provide dynamic schemes for capacity adjustment, and consider the incorporation of pricing and congestion control to enforce absolute performance bounds on top of the proportional ones. Finally, we extend our basic results to networks with general topology. View full abstract»

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  • A Unified Framework for Multipath Routing for Unicast and Multicast Traffic

    Publication Year: 2008 , Page(s): 1038 - 1051
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1215 KB) |  | HTML iconHTML  

    We study the problem of load balancing the traffic from a set of unicast and multicast sessions. The problem is formulated as an optimization problem. However, we assume that the gradient of the network cost function is not available and needs to be estimated. Multiple paths are provided between a source and a destination using application-layer overlay. We propose a novel algorithm that is based on what is known as simultaneous perturbation stochastic approximation and utilizes only noisy measurements collected and reported to the sources, using an overlay architecture. We consider three network models that reflect different sets of assumptions regarding multicast capabilities of the network. Using an analytical model we first prove the almost sure convergence of the algorithm to a corresponding optimal solution under each network model considered in this paper with decreasing step sizes. Then, we establish the weak convergence (or convergence in distribution) with a fixed step size. In addition, we investigate the benefits acquired from implementing additional multicast capabilities by studying the relative performance of our algorithm under the three network models. View full abstract»

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  • Real-Time Monitoring of Video Quality in IP Networks

    Publication Year: 2008 , Page(s): 1052 - 1065
    Cited by:  Papers (31)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (888 KB) |  | HTML iconHTML  

    This paper investigates the problem of assessing the quality of video transmitted over IP networks. Our goal is to develop a methodology that is both reasonably accurate and simple enough to support the large-scale deployments that the increasing use of video over IP are likely to demand. For that purpose, we focus on developing an approach that is capable of mapping network statistics, e.g., packet losses, available from simple measurements, to the quality of video sequences reconstructed by receivers. A first step in that direction is a loss-distortion model that accounts for the impact of network losses on video quality, as a function of application-specific parameters such as video codec, loss recovery technique, coded bit rate, packetization, video characteristics, etc. The model, although accurate, is poorly suited to large-scale, on-line monitoring, because of its dependency on parameters that are difficult to estimate in real-time. As a result, we introduce a ldquorelative qualityrdquo metric (rPSNR) that bypasses this problem by measuring video quality against a quality benchmark that the network is expected to provide. The approach offers a lightweight video quality monitoring solution that is suitable for large-scale deployments. We assess its feasibility and accuracy through extensive simulations and experiments. View full abstract»

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  • On the Race of Worms, Alerts, and Patches

    Publication Year: 2008 , Page(s): 1066 - 1079
    Cited by:  Papers (9)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (901 KB) |  | HTML iconHTML  

    We provide an analytical framework for evaluating the performance of automatic patching systems. We use it to quantify the speed of patch or alert dissemination required for worm containment. Motivated by scalability and trust issues, we consider a hierarchical system where network hosts are organized into subnets, each containing a patch server (termed superhost). Patches are disseminated to superhosts through an overlay connecting them and, after verification, to end hosts within subnets. The analytical framework accommodates a variety of overlays through the novel abstraction of a minimum broadcast curve. It also accommodates filtering of scans across subnets. The framework provides quantitative estimates that can guide system designers in dimensioning automatic patching systems. The results are obtained mathematically and verified by simulation. View full abstract»

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  • Fixed Point Analysis of Single Cell IEEE 802.11e WLANs: Uniqueness and Multistability

    Publication Year: 2008 , Page(s): 1080 - 1093
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1538 KB) |  | HTML iconHTML  

    We consider the vector fixed point equations arising out of the analysis of the saturation throughput of a single cell IEEE 802.11e (EDCA) wireless local area network with nodes that have different backoff parameters, including different arbitration interframe space (AIFS) values. We consider balanced and unbalanced solutions of the fixed point equations arising in homogeneous (i.e., one with the same backoff parameters) and nonhomogeneous networks. By a balanced fixed point, we mean one where all coordinates are equal. We are concerned, in particular, with: 1) whether the fixed point is balanced within a class, and 2) whether the fixed point is unique. Our simulations show that when multiple unbalanced fixed points exist in a homogeneous system then the time behavior of the system demonstrates severe short term unfairness (or multistability). We provide a condition for the fixed point solution to be balanced, and also a condition for uniqueness. We then extend our general fixed point analysis to capture AIFS based differentiation and the concept of virtual collision when there are multiple queues per station; again a condition for uniqueness is established. For the case of multiple queues per node, we find that a model with as many nodes as there are queues, with one queue per node, provides an excellent approximation. Implications for the use of the fixed point formulation for performance analysis are also discussed. View full abstract»

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  • The Analysis of Nash Equilibria of the One-Shot Random-Access Game for Wireless Networks and the Behavior of Selfish Nodes

    Publication Year: 2008 , Page(s): 1094 - 1107
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (859 KB) |  | HTML iconHTML  

    We address the fundamental question of whether or not there exist stable operating points in a network in which selfish nodes share a common channel, and if they exist, how the nodes behave at these stable operating points. We begin with a wireless communication network in which n nodes (agents), which might have different utility functions, contend for access on a common, wireless communication channel. We characterize this distributed multiple-access problem in terms of a one-shot random-access game, and then analyze the behavior of the nodes using the tools of game theory. We give necessary and sufficient conditions on nodes for the complete characterization of the Nash equilibria of this game for all n ges 2. We show that all centrally controlled optimal solutions are a subset of this game theoretic solution, and almost all (w.r.t. Lebesgue measure) transmission probability assignments chosen by a central authority are supported by the game theoretic solution. We analyze the behavior of the network throughput at Nash equilibria as a function of the costs of the transmitters incurred by failed transmissions. Finally, we conclude the paper with the asymptotic analysis of the system as the number of transmitters goes to infinity. We show that the asymptotic distribution of the packet arrivals converges in distribution to a Poisson random variable, and the channel throughput converges to -(c/(1+c))ln(c/(1+c)) with c > 0 being the cost of failed transmissions. We also give the best possible bounds on the rates of convergence of the packet arrival distribution and the channel throughput. View full abstract»

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  • Extending the Lifetime of Wireless Sensor Networks Through Mobile Relays

    Publication Year: 2008 , Page(s): 1108 - 1120
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1116 KB) |  | HTML iconHTML  

    We investigate the benefits of a heterogeneous architecture for wireless sensor networks (WSNs) composed of a few resource rich mobile relay nodes and a large number of simple static nodes. The mobile relays have more energy than the static sensors. They can dynamically move around the network and help relieve sensors that are heavily burdened by high network traffic, thus extending the latter's lifetime. We first study the performance of a large dense network with one mobile relay and show that network lifetime improves over that of a purely static network by up to a factor of four. Also, the mobile relay needs to stay only within a two-hop radius of the sink. We then construct a joint mobility and routing algorithm which can yield a network lifetime close to the upper bound. The advantage of this algorithm is that it only requires a limited number of nodes in the network to be aware of the location of the mobile relay. Our simulation results show that one mobile relay can at least double the network lifetime in a randomly deployed WSN. By comparing the mobile relay approach with various static energy-provisioning methods, we demonstrate the importance of node mobility for resource provisioning in a WSN. View full abstract»

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  • A Case for Hybrid Sensor Networks

    Publication Year: 2008 , Page(s): 1121 - 1132
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB) |  | HTML iconHTML  

    In this paper, we investigate the use of limited infrastructure, in the form of wires, for improving the energy efficiency of a wireless sensor network. We call such a sensor network - a wireless sensor network with a limited infrastructural support - a hybrid sensor network. The wires act as short cuts to bring down the average hop count of the network, resulting in a reduced energy dissipation per node. Our results indicate that adding a few wires to a wireless sensor network can not only reduce the average energy expenditure per sensor node, but also the non-uniformity in the energy expenditure across the sensor nodes. View full abstract»

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  • Broadcasting in Sensor Networks: The Role of Local Information

    Publication Year: 2008 , Page(s): 1133 - 1146
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (734 KB) |  | HTML iconHTML  

    Flooding based querying and broadcasting schemes have low hop-delays of Theta(1/R(n)) to reach any node that is a unit distance away, where R(n) is the transmission range of any sensor node. However, in sensor networks with large radio ranges, flooding based broadcasting schemes cause many redundant transmissions leading to a broadcast storm problem. In this paper, we study the role of geographic information and state information (i.e., memory of previous messages or transmissions) in reducing the redundant transmissions in the network. We consider three broadcasting schemes with varying levels of local information where nodes have: (i) no geographic or state information, (ii) coarse geographic information about the origin of the broadcast, and (Hi) no geographic information, but remember previously received messages. For each of these network models, we demonstrate localized forwarding algorithms for broadcast (based on geography or state information) that achieve significant reductions in the transmission overheads while maintaining hop-delays comparable to flooding based schemes. We also consider the related problem of broadcasting to a set of "spatially uniform" points in the network (lattice points) in the regime where all nodes have only a local sense of direction and demonstrate an efficient "sparse broadcast" scheme based on a branching random walk that has a low number of packet transmissions. Thus, our results show that even with very little local information, it is possible to make broadcast schemes significantly more efficient. View full abstract»

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  • Performance Optimization of Interference-Limited Multihop Networks

    Publication Year: 2008 , Page(s): 1147 - 1160
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (662 KB) |  | HTML iconHTML  

    The performance of a multihop wireless network is typically affected by the interference caused by transmissions in the same network. In a statistical fading environment, the interference effects become harder to predict. Information sources in a multihop wireless network can improve throughput and delay performance of data streams by implementing interference-aware packet injection mechanisms. Forcing packets to wait at the head of queues and coordinating packet injections among different sources enable effective control of copacket interference. In this paper, throughput and delay performance in interference-limited multihop networks is analyzed. Using nonlinear probabilistic hopping models, waiting times which jointly optimize throughput and delay performances are derived. Optimal coordinated injection strategies are also investigated as functions of the number of information sources and their separations. The resulting analysis demonstrates the interaction of performance constraints and achievable capacity in a wireless multihop network. View full abstract»

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  • Throughput-Optimal Configuration of Fixed Wireless Networks

    Publication Year: 2008 , Page(s): 1161 - 1174
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB) |  | HTML iconHTML  

    In this paper, we address the following two questions concerning the capacity and configuration of fixed wireless networks: (i) given a set of wireless nodes with arbitrary but fixed locations, and a set of data flows, what is the max-min achievable throughput? and (ii) how should the network be configured to achieve the optimum? We consider these questions from a networking standpoint assuming point-to-point links, and employ a rigorous physical layer model to model conflict relationships between them. Since we seek capacity results, we assume that the network is operated using an appropriate schedule of conflict-free link activations. We develop and investigate a novel optimization framework to determine the optimal throughput and configuration, i.e., flow routes, link activation schedules and physical layer parameters. Determining the optimal throughput is a computationally hard problem, in general. However, using a smart enumerative technique we obtain numerical results for several different scenarios of interest. We obtain several important insights into the structure of the optimal routes, schedules and physical layer parameters. Besides determining the achievable throughput, we believe that our optimization-based framework can also be used as a tool, for configuring scheduled wireless networks, such as those based on IEEE 802.16. View full abstract»

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  • On the Asymptotic Minimum Transporting Energy and Its Implication on the Wireless Network Capacity

    Publication Year: 2008 , Page(s): 1175 - 1187
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (545 KB) |  | HTML iconHTML  

    In this paper we study the asymptotic minimum energy (which is defined as the minimum transporting energy) required to transport (via multiple hops) data packets from a source to a destination. Under the assumptions that nodes are distributed according to a Poisson point process with node density n in a unit-area square and the distance between a source and a destination is of constant order, we prove that the minimum transporting energy is Theta(n (1-alpha)/2) with probability approaching one as the node density goes to infinity, where alpha is the path loss exponent. We demonstrate use of the derived results to obtain the bounds of the capacity of wireless networks that operate in UWB. In particular, we prove the transport capacity of UWB-operated networks is Theta(n (alpha-1)/2) with high probability. We also carry out simulations to validate the derived results and to estimate the constant factor associated with the bounds on the minimum energy. The simulation results indicate that the constant associated with the minimum energy converges to the source-destination distance. View full abstract»

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  • Order Optimal Delay for Opportunistic Scheduling in Multi-User Wireless Uplinks and Downlinks

    Publication Year: 2008 , Page(s): 1188 - 1199
    Cited by:  Papers (42)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (401 KB) |  | HTML iconHTML  

    We consider a one-hop wireless network with independent time varying ON/OFF channels and N users, such as a multi-user uplink or downlink. We first show that general classes of scheduling algorithms that do not consider queue backlog must incur average delay that grows at least linearly with N . We then construct a dynamic queue-length aware algorithm that maximizes throughput and achieves an average delay that is independent of N. This is the first order-optimal delay result for opportunistic scheduling with asymmetric links. The delay bounds are achieved via a technique of queue grouping together with Lyapunov drift and statistical multiplexing concepts. View full abstract»

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  • Performance Evaluation of Admission Control and Adaptive Modulation in OFDMA WiMax Systems

    Publication Year: 2008 , Page(s): 1200 - 1211
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (645 KB) |  | HTML iconHTML  

    In this paper, we study the performance of multi-cell OFDMA WiMAX systems, in both downlink and uplink. We calculate analytically the number of collisions when the number of users in each cell is known. We then calculate the QoS indicators (e.g., blocking rates, download time and bit error rates) taking into account the physical layer conditions (modulation, propagation and MIMO), the MAC layer techniques (HARQ and radio resource management algorithms) and the traffic characteristics, in a cross-layer approach. We finally evaluate the impact of using adaptive modulation and coding on the overall performance of the system. This analysis allows us to calculate the Erlang capacity of a WiMAX system. Our numerical applications then show how to choose the best admission control and modulation schemes that extend the Erlang capacity region. View full abstract»

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  • Padded Frames: A Novel Algorithm for Stable Scheduling in Load-Balanced Switches

    Publication Year: 2008 , Page(s): 1212 - 1225
    Cited by:  Papers (13)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (646 KB) |  | HTML iconHTML  

    The load-balanced Birkhoff-von Neumann switching architecture consists of two stages: a load balancer and a deterministic input-queued crossbar switch. The advantages of this architecture are its simplicity and scalability, while its main drawback is the possible out-of-sequence reception of packets belonging to the same flow. Several solutions have been proposed to overcome this problem; among the most promising are the Uniform Frame Spreading (UFS) and the Full Ordered Frames First (FOFF) algorithms. In this paper, we present a new algorithm called Padded Frames (PF), which eliminates the packet reordering problem, achieves 100% throughput, and improves the delay performance of previously known algorithms. View full abstract»

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  • On Hierarchical Traffic Grooming in WDM Networks

    Publication Year: 2008 , Page(s): 1226 - 1238
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1521 KB) |  | HTML iconHTML  

    The traffic grooming problem is of high practical importance in emerging wide-area wavelength division multiplexing (WDM) optical networks, yet it is intractable for any but trivial network topologies. In this work, we present an effective and efficient hierarchical traffic grooming framework for WDM networks of general topology, with the objective of minimizing the total number of electronic ports. At the first level of hierarchy, we decompose the network into clusters and designate one node in each cluster as the hub for grooming traffic. At the second level, the hubs form another cluster for grooming intercluster traffic. We view each (first- or second-level) cluster as a virtual star, and we present an efficient near-optimal algorithm for determining the logical topology of lightpaths to carry the traffic within each cluster. Routing and wavelength assignment is then performed directly on the underlying physical topology. We demonstrate the effectiveness of our approach by applying it to two networks of realistic size, a 32-node, 53-link topology and a 47-node, 96-link network. Comparisons to lower bounds indicate that hierarchical grooming is efficient in its use of the network resources of interest, namely, electronic ports and wavelengths. In addition to scaling to large network sizes, our hierarchical approach also facilitates the control and management of multigranular networks. View full abstract»

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    Publication Year: 2008 , Page(s): 1239
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    Freely Available from IEEE
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    Publication Year: 2008 , Page(s): 1240
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    Freely Available from IEEE
  • IEEE/ACM Transactions on Networking society information

    Publication Year: 2008 , Page(s): C3
    Save to Project icon | Request Permissions | PDF file iconPDF (39 KB)  
    Freely Available from IEEE
  • IEEE/ACM Transactions on Networking Information for authors

    Publication Year: 2008 , Page(s): C4
    Save to Project icon | Request Permissions | PDF file iconPDF (29 KB)  
    Freely Available from IEEE

Aims & Scope

The IEEE/ACM Transactions on Networking’s high-level objective is to publish high-quality, original research results derived from theoretical or experimental exploration of the area of communication/computer networking.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
R. Srikant
Dept. of Electrical & Computer Engineering
Univ. of Illinois at Urbana-Champaign