Hybrid FPMS: A New Fairness Protocol Management Scheme for Community Wireless Mesh Networks

Node cooperation during packet forwarding operations is critically important for fair resource utilization in Community Wireless Mesh Networks (CoWMNs). In a CoWMN, node cooperation is achieved by using fairness protocols specifically designed to detect and isolate malicious nodes, discourage unfair behavior, and encourage node participation in forwarding packets. In general, these protocols can be split into two groups: Incentive-based ones, which are managed centrally, and use credit allocation schemes. In contrast, reputation-based protocols that are decentralized, and rely on information exchange among neighboring nodes. Centrally managed protocols inevitably suffer from scalability problems. The decentralized, reputation-based protocols lacks in detection capability, suffer from false detections and error propagation compared to the centralized, incentive-based protocols. In this study, we present a new fairness protocol management scheme, called Hybrid FPMS that captures the superior detection capability of incentive-based fairness protocols without the scalability problems inherently expected from a centralized management scheme as a network's size and density grows. Simulation results show that Hybrid FPMS is more efficient than the current centralized approach and significantly reduces the network delays and overhead.Comment: KSII Transactions on Internet and Information Systems, 201

Diagnosing client faults using SVM-based intelligent inference from TCP packet traces

We present the Intelligent Automated Client Diagnostic (IACD) system, which only relies on inference from Transmission Control Protocol (TCP) packet traces for rapid diagnosis of client device problems that cause network performance issues. Using soft-margin Support Vector Machine (SVM) classifiers, the system (i) distinguishes link problems from client problems, and (ii) identifies characteristics unique to client faults to report the root cause of the client device problem. Experimental evaluation demonstrated the capability of the IACD system to distinguish between faulty and healthy links and to diagnose the client faults with 98% accuracy in healthy links. The system can perform fault diagnosis independent of the client's specific TCP implementation, enabling diagnosis capability on diverse range of client computers.Comment: 2011 6th International Conference on Broadband and Biomedical Communications (IB2COM

Fuzzy logic control techniques and structures for Asynchronous Transfer Mode (ATM) based multimedia networks

The research presented in this thesis aims to demonstrate that fuzzy logic is a useful tool for developing mechanisms for controlling traffc flow in ATM based multimedia networks to maintain quality of service (QoS) requirements and maximize resource utilization. The study first proposes a hierarchical, multilevel control structure for ATM networks to exploit the reported strengths of fuzzy logic at various control levels. Then, an extensive development and evaluation is presented for a subset of the proposed control architecture at the congestion control level. An ATM based multimedia network must have quite sophisticated traffc control capabilities to effectively handle the requirements of a dynamically varying mixture of voice, video and data services while meeting the required levels of performance. Feedback control techniques have an essential role for the effective and efficient management of the resources of ATM networks. However, development of conventional feedback control techniques relies on the availability of analytical system models. The characteristics of ATM networks and the complexity of service requirements cause the analytical modeling to be very difficult, if not impossible. The lack of realistic dynamic explicit models leads to substantial problems in developing control solutions for B-ISDN networks. This limits the ability of conventional techniques to directly address the control objectives for ATM networks. In the literature, several connection admission and congestion control methods for B-ISDN networks have been reported, and these have achieved mixed success. Usually they either assume heavily simplified models, or they are too complicated to implement, mainly derived using probabilistic (steady-state) models. Fuzzy logic controllers, on the other hand, have been applied successfully to the task of controlling systems for which analytical models are not easily obtainable. Fuzzy logic control is a knowledge-based control strategy that can be utilized when an explicit model of a system is not available or, the model itself, if available, is highly complex and nonlinear. In this case, the problem of control system design is based on qualitative and/or empirically acquired knowledge regarding the operation of the system. Representation of qualitative or empirically acquired knowledge in a fuzzy logic controller is achieved by linguistic expressions in the form of fuzzy relational equations. By using fuzzy relational equations, classifications related to system parameters can be derived without explicit description. The thesis presents a new predictive congestion control scheme, Fuzzy Explicit Rate Marking (FERM), which aims to avoid congestion, and by doing so minimize the cell losses, attain high server utilization, and maintain the fair use of links. The performance of the FERM scheme is extremely competitive with that of control schemes developed using traditional methods over a considerable period of time. The results of the study demonstrate that fuzzy logic control is a highly effective design tool for this type of problems, relative to the traditional methods. When controlled systems are highly nonlinear and complex, it keeps the human insight alive and accessible at the lower levels of the control hierarchy, and so higher levels can be built on this understanding. Additionally, the FERM scheme has been extended to adaptively tune (A-FERM) so that continuous automatic tuning of the parameters can be achieved, and thus be more adaptive to system changes leading to better utilization of network bandwidth. This achieves a level of robustness that is not exhibited by other congestion control schemes reported in the literature. In this work, the focus is on ATM networks rather than IP based networks. For historical reasons, and due to fundamental philosophical differences in the (earlier) approach to congestion control, the research for control of TCP/IP and ATM based networks proceeded separately. However, some convergence between them has recently become evident. In the TCP/IP literature proposals have appeared on active queue management in routers, and Explicit Congestion Notification (ECN) for IP. It is reasonably expected that, the algorithms developed in this study will be applicable to IP based multimedia networks as well

Source Specific Multicast (SSM) for MIPv6: A Survey of Current State of Standardisation and Research

IPv6, designed with the success and prior experience of IPv4, will potentially reach into larger spheres of communication devices and networks. Employing the Internet infrastructure and protocols, communications will not only be limited between traditional computer devices. The expanded addressing schema, integrated security, efficient routing and auto-configuration capability of IPv6 augurs well for mobility and wireless access on the Internet. Multicast is particularly important and has distinct advantages in mobile environments where operating frequency bands are shared between users and bandwidth is constrained. Repeat transmissions or per-request based multimedia applications are inefficient and quickly deplete available bandwidth with increasing number of users. However, the efficient use of multicast requires architectural improvements. For example, the existing Any Source Multicast (ASM) specification is burdened with various protocol complexities and subsequent deployment complications. The structurally simpler Source Specific Multicasting (SSM) model has great potential for widespread use. It is inherently easier for multicast sources configuration, has global scope and no prior network provider arrangements required. The proposed IPv6 SSM architecture is new and in the process of standardisation. This paper presents the current state of standardisation and research progress for MIPv6 SSM architecture, protocols, related components

A Simulation Study on the Performance of Integrated Switching Strategy for Traffic Management in ATM Networks

Designing effective congestion control strategies for broadband networks is known to be difficult because of the variety of dynamic parameters involved such as link speeds, burstiness of the traffic, and the distances between traffic sources and switching nodes

Performance Evaluation of Mobile IPv6 Handover Extensions in an IEEE 802.11b Wireless Network Environment

Abstract — In order to support mobile users, the basic Internet protocols have been extended with protocols (e.g., Mobile IPv6) for intercepting and forwarding packets to a mobile and possibly roaming node. Seamless roaming requires that users and applications do not experience loss of connectivity or any noticeable interruption in traffic. This is not only important for highly delay-sensitive traffic, but also for TCP-based traffic, as its performance is highly sensitive to packet loss and reordering. It is therefore imperative that handovers are initiated in such a way that the handover latency and packet loss is minimized. However, little is known about the performance of the proposed Mobile IPv6 approach in an actual network. In particular, it is not understood how different enhancement schemes for Mobile IPv6 influence essential performance metrics. This research paper is aimed at evaluating some of these enhancement techniques by extensive simulations to see how close we are to the ideal goal of attributing handover delay to the limitations of the physical hardware below the network layer. T I