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

Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

QoS provisioning in multimedia streaming

Multimedia consists of voice, video, and data. Sample applications include video conferencing, video on demand, distance learning, distributed games, and movies on demand. Providing Quality of Service (QoS) for multimedia streaming has been a difficult and challenging problem. When multimedia traffic is transported over a network, video traffic, though usually compressed/encoded for bandwidth reduction, still consumes most of the bandwidth. In addition, compressed video streams typically exhibit highly variable bit rates as well as long range dependence properties, thus exacerbating the challenge in meeting the stringent QoS requirements of multimedia streaming with high network utilization. Dynamic bandwidth allocation in which video traffic prediction can play an important role is thus needed. Prediction of the variation of the I frame size using Least Mean Square (LMS) is first proposed. Owing to a smoother sequence, better prediction has been achieved as compared to the composite MPEG video traffic prediction scheme. One problem with this LMS algorithm is its slow convergence. In Variable Bit Rate (VBR) videos characterized by frequent scene changes, the LMS algorithm may result in an extended period of intractability, and thus may experience excessive cell loss during scene changes. A fast convergent non-linear predictor called Variable Step-size Algorithm (VSA) is subsequently proposed to overcome this drawback. The VSA algorithm not only incurs small prediction errors but more importantly achieves fast convergence. It tracks scene changes better than LMS. Bandwidth is then assigned based on the predicted I frame size which is usually the largest in a Group of Picture (GOP). Hence, the Cell Loss Ratio (CLR) can be kept small. By reserving bandwidth at least equal to the predicted one, only prediction errors need to be buffered. Since the prediction error was demonstrated to resemble white noise or exhibits at most short term memory, smaller buffers, less delay, and higher bandwidth utilization can be achieved. In order to further improve network bandwidth utilization, a QoS guaranteed on-line bandwidth allocation is proposed. This method allocates the bandwidth based on the predicted GOP and required QoS. Simulations and analytical results demonstrate that this scheme provides guaranteed delay and achieves higher bandwidth utilization. Network traffic is generally accepted to be self similar. Aggregating self similar traffic can actually intensify rather than diminish burstiness. Thus, traffic prediction plays an important role in network management. Least Mean Kurtosis (LMK), which uses the negated kurtosis of the error signal as the cost function, is proposed to predict the self similar traffic. Simulation results show that the prediction performance is improved greatly as compared to the LMS algorithm. Thus, it can be used to effectively predict the real time network traffic. The Differentiated Service (DiffServ) model is a less complex and more scalable solution for providing QoS to IP as compared to the Integrated Service (IntServ) model. We propose to transport MPEG frames through various service classes of DiffServ according to the MPEG video characteristics. Performance analysis and simulation results show that our proposed approach can not only guarantee QoS but can also achieve high bandwidth utilization. As the end video quality is determined not only by the network QoS but also by the encoded video quality, we consider video quality from these two aspects and further propose to transport spatial scalable encoded videos over DiffServ. Performance analysis and simulation results show that this can provision QoS guarantees. The dropping policy we propose at the egress router can reduce the traffic load as well as the risk of congestion in other domains

Theories and Models for Internet Quality of Service

We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also briefly discussed. We then turn our attention to statistical performance guarantees, and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review recent proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support

A Testbed About Priority-Based Dynamic Connection Profiles in QoS Wireless Multimedia Networks

The ever-growing demand of high-quality broadband connectivity in mobile scenarios, as well as the Digital Divide discrimination, are boosting the development of more and more efficient wireless technologies. Despite their adaptability and relative small installation costs, wireless networks still lack a full bandwidth availability and are also subject to interference problems. In context of a Metropolitan Area Network serving a large number of users, a bandwidth increase can turn out to be neither feasible nor justified. In consequence, and in order to meet the needs of multimedia applications, bandwidth optimization techniques were designed and developed, such as Traffic Shaping, Policy-Based Traffic Management and Quality of Service (QoS). In this paper, QoS protocols are adopted and, in particular, priority-based dynamic profiles in a QoS wireless multimedia network. This technique allows to asssign different priorities to distinct applications, so as to rearrange service quality in a dynamic way and guarantee the desired performance to a given data flow

Time Driven Priority Router Implementation and First Experiments

This paper reports on the implementation of Time-Driven Priority (TDP) scheduling on a FreeBSD platform. This work is part of a TDP prototyping and demonstration project aimed at showing the implications of TDP deployment in packet-switched networks, especially benefits for real-time applications. This paper focuses on practical aspects related to the implementation of the technology on a Personal Computer (PC)-based router and presents the experimental results obtained on a testbed network. The basic building blocks of a TDP router are described and implementation choices are discussed. The relevant results achieved and here presented can be categorized into two types: qualitative results, including the successful integration of all needed blocks and the insight obtained on the complexity related to the implementation of a TDP router, and quantitative ones, including measures of achievable network utilization and of jitter experienced on a fully-loaded TDP network. The outcome demonstrates the effectiveness of the presented implementation while confirming TDP points of strengt

Advances in Internet Quality of Service

We describe recent advances in theories and architecture that support performance guarantees needed for quality of service networks. We start with deterministic computations and give applications to integrated services, differentiated services, and playback delays. We review the methods used for obtaining a scalable integrated services support, based on the concept of a stateless core. New probabilistic results that can be used for a statistical dimensioning of differentiated services are explained; some are based on classical queuing theory, while others capitalize on the deterministic results. Then we discuss performance guarantees in a best effort context; we review: methods to provide some quality of service in a pure best effort environment; methods to provide some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support

Policy-based network management of legacy equipment in Next Generation Networks

Next Generation Networks use policy-based network management and QoS protocols to provide voice services on IP networks. Large numbers of older equipment still push IP packets. We present several solutions that include legacy equipment into a PBNM and QoS system. A static design uses traffic shaping at the legacy edge. A dynamic solution uses a Quasi-PEP implemented over RSVP and COPS. Preliminary test results are presented for the static solution. Collected data shows that the solution decreases packet loss on the legacy side.Telkom, Siemens, THRI

Multi Protocol Label Switching: Quality of Service, Traffic Engineering application, and Virtual Private Network application

This thesis discusses the QoS feature, Traffic Engineering (TE) application, and Virtual Private Network (VPN) application of the Multi Protocol Label Switching (MPLS) protocol. This thesis concentrates on comparing MPLS with other prominent technologies such as Internet Protocol (IP), Asynchronous Transfer Mode (ATM), and Frame Relay (FR). MPLS combines the flexibility of Internet Protocol (IP) with the connection oriented approach of Asynchronous Transfer Mode (ATM) or Frame Relay (FR). Section 1 lists several advantages MPLS brings over other technologies. Section 2 covers architecture and a brief description of the key components of MPLS. The information provided in Section 2 builds a background to compare MPLS with the other technologies in the rest of the sections. Since it is anticipate that MPLS will be a main core network technology, MPLS is required to work with two currently available QoS architectures: Integrated Service (IntServ) architecture and Differentiated Service (DiffServ) architecture. Even though the MPLS does not introduce a new QoS architecture or enhance the existing QoS architectures, it works seamlessly with both QoS architectures and provides proper QoS support to the customer. Section 3 provides the details of how MPLS supports various functions of the IntServ and DiffServ architectures. TE helps Internet Service Provider (ISP) optimize the use of available resources, minimize the operational costs, and maximize the revenues. MPLS provides efficient TE functions which prove to be superior to IP and ATM/FR. Section 4 discusses how MPLS supports the TE functionality and what makes MPLS superior to other competitive technologies. ATM and FR are still required as a backbone technology in some areas where converting the backbone to IP or MPLS does not make sense or customer demands simply require ATM or FR. In this case, it is important for MPLS to work with ATM and FR. Section 5 highlights the interoperability issues and solutions for MPLS while working in conjunction with ATM and FR. In section 6, various VPN tunnel types are discussed and compared with the MPLS VPN tunnel type. The MPLS VPN tunnel type is concluded as an optimal tunnel approach because it provides security, multiplexing, and the other important features that are reburied by the VPN customer and the ISP. Various MPLS layer 2 and layer 3 VPN solutions are also briefly discussed. In section 7 I conclude with the details of an actual implementation of a layer 3 MPLS VPN solution that works in conjunction with Border Gateway Protocol (BGP)