Delivering video services over IP networks

The main goal pursued in this Thesis is to contribute towards the design and development of an end-to-end solution/system that would assist in reliable, consistence, less packet-loss delivery of high-quality video signals of pre-recorded presentations, training lectures, live events such as seminars over standard IP networks. This Thesis will focus on the existing Internet Service Provider, Oman Telecommunications Company (Omantel) and its best delivery of high-bandwidth data such as video to its Local and regional offices and departments over IP networks. This video-over-IP system aims to accumulate the technical scientific knowledge required to be able to offer high-quality video, which is fully scalable over IP networks. It aims to convert this knowledge into experimental prototypes, which, after the Thesis, can be developed into an integrated generic environment for Video-over-IP service development and content production. The objective is to initially define the functionality of content Services that can be incorporated into the operations of Oman telecommunications company networks. Then define the functional characteristics and system requirements necessary for the deployment of content streaming services over Omantel IP based networks. The design of this system would be combined with streaming high-quality video, while maintaining scalability and bandwidth efficiencies required for large-scale enterprise deployment. The design would encompass various components that are needed to capture, store and deliver streaming video to desktops. It will investigate on what is required to deliver quality video over Omantel IP networks and will recommend the actual products and solutions for achieving the end result

QoS-based multipath routing for the Internet

The new generation of network services is being developed for incorporation in communication infrastructure. These services, generally called Quality of Services (QoS), should accommodate data file, video, and audio applications. The different performance requirements of these applications necessitate a re-examination of the main architectural components of today\u27s networks, which were designed to support traditional data applications. Routing, which determines the sequence of network nodes a packet traverses between source and destination, is one such component. Here, we examine the potential routing problems in future Internet and discuss the advantages of class-based multi-path routing methods. The result is a new approach to routing in packet-switched networks, which is called Two-level Class-based Multipath routing with Prediction (TCMP). In TCMP, we compute multiple paths between each source and destination based on link propagation delay and bottleneck bandwidth. A leaky bucket is adopted in each router to monitor the bottleneck bandwidth on equal paths during the network\u27s stable period, and to guide its traffic forwarDing The TCMP can avoid frequent flooding of routing information in a dynamic routing method; therefore, it can be applied to large network topologies

Performance evaluation of multicast networks and service differentiation mechanisms in IP networks

The performance of a communication network depends on how well the network is designed in terms of delivering the level of service required by a given type of traffic. The field of teletraffic theory is concerned with quantifying the three-way relationship between the network, its level of service and the traffic arriving at the network. In this thesis, we study three different problems concerning this three-way relationship and present models to assist in designing and dimensioning networks to satisfy the different quality of service demands. In the first part of the thesis, we consider service differentiation mechanisms in packet-switched IP networks implementing a Differentiated Services (DiffServ) architecture. We study how bandwidth can be divided in a weighted fair manner between persistent elastic TCP flows, and between these TCP flows and streaming real-time UDP flows. To this end, we model the traffic conditioning and scheduling mechanisms on the packet and the flow level. We also model the interaction of these DiffServ mechanisms with the TCP congestion control mechanism and present closed-loop models for the sending rate of a TCP flow that reacts to congestion signals from the network. In the second part, we concentrate on non-persistent elastic TCP traffic in IP networks and study how flows can be differentiated in terms of mean delay by giving priority to flows based on their age. We study Multi Level Processor Sharing (MLPS) disciplines, where jobs are classified into levels based on their age or attained service. Between levels, a strict priority discipline is applied; the level containing the youngest jobs has the highest priority. Inside a particular level, any scheduling discipline could be used. We present an implementation proposal of a two-level discipline, PS+PS, with the Processor Sharing discipline used inside both levels. We prove that, as long as the hazard rate of the job-size distribution is decreasing, which is the case for Internet traffic, PS+PS, and any MLPS discipline that favors young jobs, is better than PS with respect to overall mean delay. In the final part, we study distribution-type streaming traffic in a multicast network, where there is, at most, one copy of each channel transmission in each network link, and quantify the blocking probability. We derive an exact blocking probability algorithm for multicast traffic in a tree network based on the convolution and truncation algorithm for unicast traffic. We present a new convolution operation, the OR-convolution, to suit the transmission principle of multicast traffic, and a new truncation operator to take into account the case of having both unicast and multicast traffic in the network. We also consider different user models derived from the single-user model.reviewe

Learning algorithms for the control of routing in integrated service communication networks

There is a high degree of uncertainty regarding the nature of traffic on future integrated service networks. This uncertainty motivates the use of adaptive resource allocation policies that can take advantage of the statistical fluctuations in the traffic demands. The adaptive control mechanisms must be 'lightweight', in terms of their overheads, and scale to potentially large networks with many traffic flows. Adaptive routing is one form of adaptive resource allocation, and this thesis considers the application of Stochastic Learning Automata (SLA) for distributed, lightweight adaptive routing in future integrated service communication networks. The thesis begins with a broad critical review of the use of Artificial Intelligence (AI) techniques applied to the control of communication networks. Detailed simulation models of integrated service networks are then constructed, and learning automata based routing is compared with traditional techniques on large scale networks. Learning automata are examined for the 'Quality-of-Service' (QoS) routing problem in realistic network topologies, where flows may be routed in the network subject to multiple QoS metrics, such as bandwidth and delay. It is found that learning automata based routing gives considerable blocking probability improvements over shortest path routing, despite only using local connectivity information and a simple probabilistic updating strategy. Furthermore, automata are considered for routing in more complex environments spanning issues such as multi-rate traffic, trunk reservation, routing over multiple domains, routing in high bandwidth-delay product networks and the use of learning automata as a background learning process. Automata are also examined for routing of both 'real-time' and 'non-real-time' traffics in an integrated traffic environment, where the non-real-time traffic has access to the bandwidth 'left over' by the real-time traffic. It is found that adopting learning automata for the routing of the real-time traffic may improve the performance to both real and non-real-time traffics under certain conditions. In addition, it is found that one set of learning automata may route both traffic types satisfactorily. Automata are considered for the routing of multicast connections in receiver-oriented, dynamic environments, where receivers may join and leave the multicast sessions dynamically. Automata are shown to be able to minimise the average delay or the total cost of the resulting trees using the appropriate feedback from the environment. Automata provide a distributed solution to the dynamic multicast problem, requiring purely local connectivity information and a simple updating strategy. Finally, automata are considered for the routing of multicast connections that require QoS guarantees, again in receiver-oriented dynamic environments. It is found that the distributed application of learning automata leads to considerably lower blocking probabilities than a shortest path tree approach, due to a combination of load balancing and minimum cost behaviour

A Survey of Differentiated Services Proposals for the Internet

Abstract TR/1998/020 Technical Report SSC/1998/020 Authors: Constant Gbaguidi, Hans J. Einsiedler, Paul Hurley, Werner Almesberger and Jean-Pierre Hubaux Date: Title: A Survey of Differentiated Services Proposals for the Internet Abstract Differentiated services are a suitable solution to Quality of Service (QoS) provisioning in the Internet while the number of users keeps growing. The solution is suitable, because it scales well with increasing number of network users and it does not alter the current Internet paradigm much. In this article, we review the state of the art in this ÒnewÓ area, and compare some of the main existing differentiated services architectures. We outline the common solutions across these architectures, thus paving the road to a unified architecture. Lastly, we mention the issues that have not been thoroughly addressed yet

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

Selective Flooding for Better QoS Routing

Quality-of-service (QoS) requirements for the timely delivery of real-time multimedia raise new challenges for the networking world. A key component of QoS is QoS routing which allows the selection of network routes with sufficient resources for requested QoS parameters. Several techniques have been proposed in the literature to compute QoS routes, most of which require dynamic update of link-state information across the Internet. Given the growing size of the Internet, it is becoming increasingly difficult to gather up-to-date state information in a dynamic environment. We propose a new technique to compute QoS routes on the Internet in a fast and efficient manner without any need for dynamic updates. Our method, known as Selective Flooding, checks the state of the links on a set of pre-computed routes from the source to the destination in parallel and based on this information computes the best route and then reserves resources. We implemented Selective Flooding on a QoS routing simulator and evaluated the performance of Selective Flooding compared to source routing for a variety of network parameters. We find Selective Flooding consistently outperforms source routing in terms of call-blocking rate and outperforms source routing in terms of network overhead for some network conditions. The contributions of this thesis include the design of a new QoS routing algorithm, Selective Flooding, extensive evaluation of Selective Flooding under a variety of network conditions and a working simulation model for future research

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

SPAD: a distributed middleware architecture for QoS enhanced alternate path discovery

In the next generation Internet, the network will evolve from a plain communication medium into one that provides endless services to the users. These services will be composed of multiple cooperative distributed application elements. We name these services overlay applications. The cooperative application elements within an overlay application will build a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS experienced on the communication paths of the corresponding overlay association. In this paper, we present SPAD (Super-Peer Alternate path Discovery), a distributed middleware architecture that aims at providing enhanced QoS between end-points within an overlay association. To achieve this goal, SPAD provides a complete scheme to discover and utilize composite alternate end-to end paths with better QoS than the path given by the default IP routing mechanisms

Dynamic bandwidth allocation in multi-class IP networks using utility functions.

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