Virtual RTCP: A Case Study of Monitoring and Repair for UDP-based IPTV Systems

IPTV systems have seen widespread deployment, but often lack robust mechanisms for monitoring the quality of experience. This makes it difficult for network operators to ensure that their services match the quality of traditional broadcast TV systems, leading to consumer dissatisfaction. We present a case study of virtual RTCP, a new framework for reception quality monitoring and reporting for UDP-encapsulated MPEG video delivered over IP multicast. We show that this allows incremental deployment of reporting infrastructure, coupled with effective retransmission-based packet loss repair

Design of traffic shaper / scheduler for packet switches and DiffServ networks : algorithms and architectures

The convergence of communications, information, commerce and computing are creating a significant demand and opportunity for multimedia and multi-class communication services. In such environments, controlling the network behavior and guaranteeing the user\u27s quality of service is required. A flexible hierarchical sorting architecture which can function either as a traffic shaper or a scheduler according to the requirement of the traffic load is presented to meet the requirement. The core structure can be implemented as a hierarchical traffic shaper which can support a large number of connections with a wide variety of rates and burstiness without the loss of the granularity in cells\u27 conforming departure time. The hierarchical traffic shaper can implement the exact sorting scheme with a substantial reduced memory size by using two stages of timing queues, and with substantial reduction in complexity, without introducing any sorting inaccuracy. By setting a suitable threshold to the length of the departure queue and using a lookahead algorithm, the core structure can be converted to a hierarchical rateadaptive scheduler. Based on the traffic load, it can work as an exact sorting traffic shaper or a Generic Cell Rate Algorithm (GCRA) scheduler. Such a rate-adaptive scheduler can reduce the Cell Transfer Delay and the Maximum Memory Occupancy greatly while keeping the fairness in the bandwidth assignment which is the inherent characteristic of GCRA. By introducing a best-effort queue to accommodate besteffort traffic, the hierarchical sorting architecture can be changed to a near workconserving scheduler. It assigns remaining bandwidth to the best-effort traffic so that it improves the utilization, of the outlink while it guarantees the quality of service requirements of those services which require quality of service guarantees. The inherent flexibility of the hierarchical sorting architecture combined with intelligent algorithms determines its multiple functions. Its implementation not only can manage buffer and bandwidth resources effectively, but also does not require no more than off-the-shelf hardware technology. The correlation of the extra shaping delay and the rate of the connections is revealed, and an improved fair traffic shaping algorithm, Departure Event Driven plus Completing Service Time Resorting algorithm, is presented. The proposed algorithm introduces a resorting process into Departure Event Driven Traffic Shaping Algorithm to resolve the contention of multiple cells which are all eligible for transmission in the traffic shaper. By using the resorting process based on each connection\u27s rate, better fairness and flexibility in the bandwidth assignment for connections with wide range of rates can be given. A Dual Level Leaky Bucket Traffic Shaper(DLLBTS) architecture is proposed to be implemented at the edge nodes of Differentiated Services Networks in order to facilitate the quality of service management process. The proposed architecture can guarantee not only the class-based Service Level Agreement, but also the fair resource sharing among flows belonging to the same class. A simplified DLLBTS architecture is also given, which can achieve the goals of DLLBTS while maintain a very low implementation complexity so that it can be implemented with the current VLSI technology. In summary, the shaping and scheduling algorithms in the high speed packet switches and DiffServ networks are studied, and the intelligent implementation schemes are proposed for them

DSL-based triple-play services

This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.

Some aspects of traffic control and performance evaluation of ATM networks

The emerging high-speed Asynchronous Transfer Mode (ATM) networks are expected to integrate through statistical multiplexing large numbers of traffic sources having a broad range of statistical characteristics and different Quality of Service (QOS) requirements. To achieve high utilisation of network resources while maintaining the QOS, efficient traffic management strategies have to be developed. This thesis considers the problem of traffic control for ATM networks. The thesis studies the application of neural networks to various ATM traffic control issues such as feedback congestion control, traffic characterization, bandwidth estimation, and Call Admission Control (CAC). A novel adaptive congestion control approach based on a neural network that uses reinforcement learning is developed. It is shown that the neural controller is very effective in providing general QOS control. A Finite Impulse Response (FIR) neural network is proposed to adaptively predict the traffic arrival process by learning the relationship between the past and future traffic variations. On the basis of this prediction, a feedback flow control scheme at input access nodes of the network is presented. Simulation results demonstrate significant performance improvement over conventional control mechanisms. In addition, an accurate yet computationally efficient approach to effective bandwidth estimation for multiplexed connections is investigated. In this method, a feed forward neural network is employed to model the nonlinear relationship between the effective bandwidth and the traffic situations and a QOS measure. Applications of this approach to admission control, bandwidth allocation and dynamic routing are also discussed. A detailed investigation has indicated that CAC schemes based on effective bandwidth approximation can be very conservative and prevent optimal use of network resources. A modified effective bandwidth CAC approach is therefore proposed to overcome the drawback of conventional methods. Considering statistical multiplexing between traffic sources, we directly calculate the effective bandwidth of the aggregate traffic which is modelled by a two-state Markov modulated Poisson process via matching four important statistics. We use the theory of large deviations to provide a unified description of effective bandwidths for various traffic sources and the associated ATM multiplexer queueing performance approximations, illustrating their strengths and limitations. In addition, a more accurate estimation method for ATM QOS parameters based on the Bahadur-Rao theorem is proposed, which is a refinement of the original effective bandwidth approximation and can lead to higher link utilisation

Simulation and performance of a statistical multiplexer in an ATM network

This report examines some of the issues arising m the implementation of statistical multiplexing in a broadband Integrated digital services network (B-ISDN) by analysis and simulation The BISDN concept is introduced and described. A review o f the current areas of research is given along with some of the important issues as they relate to telephone traffic. The report then focuses on the problem o f multiplexing voice traffic. A typical voice source is analysed and the traffic characteristics which result are described. The concept of statistical multiplexing is mtroduced. A review of the current literature studies relating to the problems of analysing multiplexed sources is given, with particular reference to the concept of cell level and burst level queues being separate and disparate components requiring different analytical approaches. Several models are mtroduced including the 3-state model not previously described in the literature. The queue behaviour resulting from a large number of superposed lmes is analysed as a simplified Markov process and the results are used to argue that it is not feasible to provide buffers for nodes which multiplex a large number of low intensity sources. The problem of scaling small models up to realistic situations is discussed. An approach to simulating the problem is described along with algorithms for implementing the basic elements. A senes of results derived from the described simulation are presented and analysed. The report concludes that statistical multiplexing is feasible, but with certain limits as to the type of traffic which can be supported

Dynamic bandwidth allocation in ATM networks

Includes bibliographical references.This thesis investigates bandwidth allocation methodologies to transport new emerging bursty traffic types in ATM networks. However, existing ATM traffic management solutions are not readily able to handle the inevitable problem of congestion as result of the bursty traffic from the new emerging services. This research basically addresses bandwidth allocation issues for bursty traffic by proposing and exploring the concept of dynamic bandwidth allocation and comparing it to the traditional static bandwidth allocation schemes

Investigation of delay jitter of heterogeneous traffic in broadband networks

Scope and Methodology of Study: A critical challenge for both wired and wireless networking vendors and carrier companies is to be able to accurately estimate the quality of service (QoS) that will be provided based on the network architecture, router/switch topology, and protocol applied. As a result, this thesis focuses on the theoretical analysis of QoS parameters in term of inter-arrival jitter in differentiated services networks by deploying analytic/mathematical modeling technique and queueing theory, where the analytic model is expressed in terms of a set of equations that can be solved to yield the desired delay jitter parameter. In wireless networks with homogeneous traffic, the effects on the delay jitter in reference to the priority control scheme of the ARQ traffic for the two cases of: 1) the ARQ traffic has a priority over the original transmission traffic; and 2) the ARQ traffic has no priority over the original transmission traffic are evaluated. In wired broadband networks with heterogeneous traffic, the jitter analysis is conducted and the algorithm to control its effect is also developed.Findings and Conclusions: First, the results show that high priority packets always maintain the minimum inter-arrival jitter, which will not be affected even in heavy load situation. Second, the Gaussian traffic modeling is applied using the MVA approach to conduct the queue length analysis, and then the jitter analysis in heterogeneous broadband networks is investigated. While for wireless networks with homogeneous traffic, binomial distribution is used to conduct the queue length analysis, which is sufficient and relatively easy compared to heterogeneous traffic. Third, develop a service discipline called the tagged stream adaptive distortion-reducing peak output-rate enforcing to control and avoid the delay jitter increases without bound in heterogeneous broadband networks. Finally, through the analysis provided, the differential services, was proved not only viable, but also effective to control delay jitter. The analytic models that serve as guidelines to assist network system designers in controlling the QoS requested by customer in term of delay jitter

Adaptation of variable-bit-rate compressed video for transport over a constant-bit-rate communication channel in broadband networks.

by Chi-yin Tse.Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 118-[121]).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Video Compression and Transport --- p.2Chapter 1.2 --- VBR-CBR Adaptation of Video Traffic --- p.5Chapter 1.3 --- Research Contributions --- p.7Chapter 1.3.1 --- Spatial Smoothing: Video Aggregation --- p.8Chapter 1.3.2 --- Temporal Smoothing: A Control-Theoretic Study。 --- p.8Chapter 1.4 --- Organization of Thesis --- p.9Chapter 2 --- Preliminaries --- p.13Chapter 2.1 --- MPEG Compression Scheme --- p.13Chapter 2.2 --- Problems of Transmitting MPEG Video --- p.17Chapter 2.3 --- Two-layer Coding and Transport Strategy --- p.19Chapter 2.3.1 --- Framework of MPEG-based Layering --- p.19Chapter 2.3.2 --- Transmission of GS and ES --- p.20Chapter 2.3.3 --- Problems of Two-layer Video Transmission --- p.20Chapter 3 --- Video Aggregation --- p.24Chapter 3.1 --- Motivation and Basic Concept of Video Aggregation --- p.25Chapter 3.1.1 --- Description of Video Aggregation --- p.28Chapter 3.2 --- MPEG Video Aggregation System --- p.29Chapter 3.2.1 --- Shortcomings of the MPEG Video Bundle Scenario with Two-Layer Coding and Cell-Level Multiplexing --- p.29Chapter 3.2.2 --- MPEG Video Aggregation --- p.31Chapter 3.2.3 --- MPEG Video Aggregation System Architecture --- p.33Chapter 3.3 --- Variations of MPEG Video Aggregation System --- p.35Chapter 3.4 --- Experimental Results --- p.38Chapter 3.4.1 --- Comparison of Video Aggregation and Cell-level Multi- plexing --- p.40Chapter 3.4.2 --- Varying Amount of the Allocated Bandwidth --- p.48Chapter 3.4.3 --- Varying Number of Sequences --- p.50Chapter 3.5 --- Conclusion --- p.53Chapter 3.6 --- Appendix: Alternative Implementation of MPEG Video Aggre- gation --- p.53Chapter 3.6.1 --- Profile Approach --- p.54Chapter 3.6.2 --- Bit-Plane Approach --- p.54Chapter 4 --- A Control-Theoretic Study of Video Traffic Adaptation --- p.58Chapter 4.1 --- Review of Previous Adaptation Schemes --- p.60Chapter 4.1.1 --- A Generic Model for Adaptation Scheme --- p.60Chapter 4.1.2 --- Objectives of Adaptation Controller --- p.61Chapter 4.2 --- Motivation for Control-Theoretic Study --- p.64Chapter 4.3 --- Linear Feedback Controller Model --- p.64Chapter 4.3.1 --- Encoder Model --- p.65Chapter 4.3.2 --- Adaptation Controller Model --- p.69Chapter 4.4 --- Analysis --- p.72Chapter 4.4.1 --- Stability --- p.73Chapter 4.4.2 --- Robustness against Coding-mode Switching --- p.83Chapter 4.4.3 --- Unit-Step Responses and Unit-Sample Responses --- p.84Chapter 4.5 --- Implementation --- p.91Chapter 4.6 --- Experimental Results --- p.95Chapter 4.6.1 --- Overall Performance of the Adaptation Scheme --- p.97Chapter 4.6.2 --- Weak-Control verus Strong-Control --- p.99Chapter 4.6.3 --- Varying Amount of Reserved Bandwidth --- p.101Chapter 4.7 --- Conclusion --- p.103Chapter 4.8 --- Appendix I: Further Research --- p.103Chapter 4.9 --- Appendix II: Review of Previous Adaptation Schemes --- p.106Chapter 4.9.1 --- Watanabe. et. al.'s Scheme --- p.106Chapter 4.9.2 --- MPEG's Scheme --- p.107Chapter 4.9.3 --- Lee et.al.'s Modification --- p.109Chapter 4.9.4 --- Chen's Adaptation Scheme --- p.110Chapter 5 --- Conclusion --- p.116Bibliography --- p.11

A study of multiplexing on to a variable-bit rate output channel in integrated-service networks.

by Chan-weng Lai.Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 81-[83]).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Where May Soft Multiplexing Occur? --- p.2Chapter 1.1.1 --- Multiplexing VC's on to a VP --- p.2Chapter 1.1.2 --- Virtual Private Networks --- p.5Chapter 1.2 --- Survey of Previously Proposed Hard Multiplexing Schemes --- p.7Chapter 1.3 --- Contributions of This Thesis --- p.8Chapter 1.4 --- Organization of This Thesis --- p.10Chapter 2 --- "Effect of (δ,p) Channels in ATM Networks" --- p.12Chapter 2.1 --- Leaky Bucket --- p.13Chapter 2.2 --- "(δ, p) Channel" --- p.14Chapter 2.3 --- "Comparison of Deterministic VP's and(δ, p) VP's" --- p.17Chapter 2.4 --- A Simulation Study : The Effect of δ --- p.20Chapter 2.5 --- Summary of This Chapter --- p.23Chapter 3 --- Soft-Multiplexing Scheduling Schemes --- p.26Chapter 3.1 --- Issues in Soft Multiplexing --- p.27Chapter 3.2 --- First Come First Serve (FCFS) --- p.30Chapter 3.3 --- Fixed-resource Allocation --- p.32Chapter 3.4 --- Excess Token Passing --- p.35Chapter 3.5 --- Simulation Results --- p.38Chapter 3.6 --- Summary of This Chapter --- p.42Chapter 4 --- Analysis of Rate Proportional Token Passing --- p.44Chapter 4.1 --- The Fictitious System --- p.45Chapter 4.2 --- Leaky-Bucket-Controlled Sources --- p.49Chapter 4.3 --- Delay Bound for All Work Conserving Soft Multiplexers --- p.51Chapter 4.4 --- The All-Greedy Bound in a RPTP Multiplexer --- p.53Chapter 4.5 --- Calculation of the Worst-Case Delay in a RPTP Multiplexer --- p.56Chapter 4.6 --- Summary of This Chapter --- p.61Chapter 5 --- Implementation of RPTP --- p.63Chapter 5.1 --- Virtual Time Implementation --- p.64Chapter 5.2 --- Leaky Bucket Implementation --- p.70Chapter 5.3 --- Summary of This Chapter --- p.72Chapter 6 --- Conclusion --- p.73Chapter A --- End-to-end Delay/Backlog Bound in ATM Networks --- p.76Bibliography --- p.8