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

Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters

Design of an adaptive-rate video-streaming service with different classes of users

The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

Design of an adaptive-rate video-streaming service with different classes of users

The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

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

Resource Allocation and Mobility Prediction Algorithms for Multimedia Wireless Cellular Networks

Among the issues the telecommunication industry is the demand for multimedia applications with Quality of Service (QoS) in wireless/mobile networks. In the face of this increasingly complex traffic mix, where each service imposes different requirements, QoS provisioning and guarantee for multimedia services have become increasingly important. This is partially due to the users' requirements and poses a difficult challenge for network service providers. The tasks are more challenging than those in the wired networks due to the shortage of resources and the mobility present in wireless networks. The mobility factor causes severe fluctuations of resource usage. In this research, the QoS provisioning and resource utilization for multimedia services in wireless/mobile networks aspects are addressed. The first proposed scheme is called Adaptive Multi-Class Services Controller scheme (AMCSC). This scheme harnesses the combinations of Call Admission Control (CAC), an Adaptive Bandwidth Allocation (ABA) algorithm with micro-Acceptable Bandwidth Level (micro-ABL) and the Connection Management Table (CMT). The specific objective in designing the AMCSC Scheme is to reduce the New Connection Blocking Probability (NCBP) and the Handoff Connection Dropping Probability (HCDP) by managing resource allocation to address. The insufficient resource problem is experienced by the MTs. This scheme supports multiple classes of non-adaptive and adaptive multimedia services with diverse QoS requirements. The second proposed scheme is a bandwidth reservation scheme based on Mobility Prediction Scheme (MPS). Two proposed MPSs are deployed to predict the mobility movement of mobiles. The first MPS obtains the user mobility information by Received Signal Strength (RSS) which also includes the direction of the MT. This is enhanced based also on the position of the MT within a sector and zones of the cell. The second MPS obtains the user mobility information using the road map information of the cell and the integrated RSS and Global Position System (GPS) measurements. The simulation results show that the proposed scheme enhances the estimation of the target cell. This shown by the reduction of the signalling traffic in wireless cellular networks, reduction of the number of terminated ongoing calls of non-real time traffic and reduction of the number of cancelled reservation due to false reservation. The third proposed framework is an integration of the AMCSC scheme and the bandwidth reservation done based on the MPS. This integration is used to achieve the ideal balance between the users' QoS guarantee of multiple classes of wireless multimedia and maximizing the bandwidth utilization. The performance result of the proposed framework has proven to improve the achieved performance metrics. The performances analysis in this research is discrete simulation. The proposed schemes have proven to enhance the performance in terms of NCBP and HCDP for each type of traffic, management the resource for multiple traffics with diverse requirement, bandwidth utilization and predicting the target cell in the right time and place

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

Application of learning algorithms to traffic management in integrated services networks.

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