Adaptive Resource Management for Flow-Based IP/ATM Hybrid Switching Systems

This paper addresses a fundamental problem in resource management for flow-based hybrid switching systems. Such systems aim at efficient transport of layer-3 connectionless IP traffic over layer-2 connection-oriented ATM switching fabrics. One idea behind flow-based hybrid switching is to decompose individual IP packet streams into flows and then to classify them into short-lived and long-lived flows. While the short-lived flows are good for forwarding by the embedded software through permanent virtual connections (PVC's), the long-lived flows are more effectively transmitted by hardware through switched virtual connections (SVC's). Clearly the flow identification/classification mechanism will have great impact on the utilization of the system's resources. Unlike the traditional emphasis on resources such as link bandwidth and cell buffer size, our paper focuses on the resources which are directly associated with packet processing power, signaling capacity, and flow cache table size. Our study indicates that the presently available static flow classification methods have a vital shortcoming in balancing the utilization of the system's resources. We propose a novel approach for adaptive flow classification based on the min--max objective for the system resource utilizations to match with the time-varying traffic/resource characteristics. Based on the monotone properties and sensitivity analysis of the resource utilizations as functions of the control parameters, we first prove that the optimal solution of the static min--max problem is achieved at a unique balance point for the resource utilizations. With the intuition gained from the static results, we then design an adaptive controller formulated as a hierarchical stochastic automata control system with local search. T..

Proposal and performance analysis of a combined input and output queuing packet switch

Orientador: Shusaburo MotoyamaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Neste trabalho é proposto um comutador de pacotes baseado em uma estrutura crossbar com m enlaces paralelos internos, denominado comutador CEP (Comutador Crossbar de Enlaces Paralelos), e com facilidade para prover qualidade de serviço (QoS ¿ Quality of Service). O comutador proposto utiliza uma combinação de filas na entrada e na saída. Os pacotes são transferidos dos buffers de entrada para os buffers de saída através de mxN linhas internas. Como as linhas internas e externas operam com a mesma velocidade, não há necessidade de aumentar a velocidade do clock interno, fazendo com que a estrutura proposta seja apropriada para comutadores de alta velocidade. O desempenho do comutador CEP é analisado admitindo pacotes de tamanho fixo (célula ATM) e pacotes de tamanho variável. O tempo médio de atraso dos pacotes e o tamanho médio das filas de entrada e de saída são avaliados por simulação e/ou por modelos analíticos, utilizando teoria de filasAbstract: A QoS (Quality of Service) provisioned CIOQ (Combined Input Output Queuing) switch using crossbar structure with m parallel lines per output port is proposed in this work. The packets at input buffers are transferred to the output buffers by means of mxN internal lines. Since all internal lines have the same speed as external links, no internal clock speedup is required so that the proposed structure is suited for high-speed switches. Switch models for analysis are proposed for both fixed and variable packet lengths and their performances, in terms of average packet waiting time and average queue size for both input and output buffers, are evaluated by simulation and/or analytically by means of queuing theory. The proposed switch also presents a feature that facilitates the choice of scheduler in order to satisfy the QoS of each class of serviceDoutoradoTelecomunicações e TelemáticaDoutor em Engenharia Elétric

Towards automatic traffic classification and estimation for available bandwidth in IP networks.

Growing rapidly, today's Internet is becoming more difficult to manage. A good understanding of what kind of network traffic classes are consuming network resource as well as how much network resource is available is important for many management tasks like QoS provisioning and traffic engineering. In the light of these objectives, two measurement mechanisms have been explored in this thesis. This thesis explores a new type of traffic classification scheme with automatic and accurate identification capability. First of all, the novel concept of IP flow profile, a unique identifier to the associated traffic class, has been proposed and the relevant model using five IP header based contexts has been presented. Then, this thesis shows that the key statistical features of each context, in the IP flow profile, follows a Gaussian distribution and explores how to use Kohonen Neural Network (KNN) for the purpose of automatically producing IP flow profile map. In order to improve the classification accuracy, this thesis investigates and evaluates the use of PCA for feature selection, which enables the produced patterns to be as tight as possible since tight patterns lead to less overlaps among patterns. In addition, the use of Linear Discriminant Analysis and alternative KNN maps has been investigated as to deal with the overlap issue between produced patterns. The entirety of this process represents a novel addition to the quest for automatic traffic classification in IP networks. This thesis also develops a fast available bandwidth measurement scheme. It firstly addresses the dynamic problem for the one way delay (OWD) trend detection. To deal with this issue, a novel model - asymptotic OWD Comparison (AOC) model for the OWD trend detection has been proposed. Then, three statistical metrics SOT (Sum of Trend), PTC (Positive Trend Checking) and CTC (Complete Trend Comparison) have been proposed to develop the AOC algorithms. To validate the proposed AOC model, an avail-bw estimation tool called Pathpair has been developed and evaluated in the Planetlah environment