CAM04-1: Admission control in self aware networks

The worldwide growth in broadband access and multimedia traffic has led to an increasing need for Quality- of-Service (QoS) in networks. Real time network applications require a stable, reliable, and predictable network that will guarantee packet delivery under QoS constraints. Network self- awareness through on-line measurement and adaptivity in response to user needs is one way to advance user QoS when overall network conditions can change, while admission control (AC) is an approach that has been commonly used to reduce traffic congestion and to satisfy users' QoS requests. The purpose of this paper is to describe a novel measurement-based admission control algorithm which bases its decision on different QoS metrics that users can specify. The self-observation and self- awareness capabilities of the network are exploited to collect data that allows an AC algorithm to decide whether to admit users based on their QoS needs, and the QoS impact they will have on other users. The approach we propose finds whether feasible paths exist for the projected incoming traffic, and estimates the impact that the newly accepted traffic will have on the QoS of pre-existing connections. The AC decision is then taken based on the outcome of this analysis

CAM04-1: Admission control in self aware networks

The worldwide growth in broadband access and multimedia traffic has led to an increasing need for Quality- of-Service (QoS) in networks. Real time network applications require a stable, reliable, and predictable network that will guarantee packet delivery under QoS constraints. Network self- awareness through on-line measurement and adaptivity in response to user needs is one way to advance user QoS when overall network conditions can change, while admission control (AC) is an approach that has been commonly used to reduce traffic congestion and to satisfy users' QoS requests. The purpose of this paper is to describe a novel measurement-based admission control algorithm which bases its decision on different QoS metrics that users can specify. The self-observation and self- awareness capabilities of the network are exploited to collect data that allows an AC algorithm to decide whether to admit users based on their QoS needs, and the QoS impact they will have on other users. The approach we propose finds whether feasible paths exist for the projected incoming traffic, and estimates the impact that the newly accepted traffic will have on the QoS of pre-existing connections. The AC decision is then taken based on the outcome of this analysis

Controlling Access To Conserve Qos In Autonomous Network Using Network Simulator

Continuous applications made a requirement for system Quality of Service (QoS). This significance prompted the improvement of self-sufficient systems that utilization versatile bundle directing with the end goal to give the most ideal QoS. Affirmation Control (AC) is a system which makes those systems a pace further in ensuring bundle conveyance even under strict QoS imperatives. QoS all through the time of every single acknowledged association in the system. The effect that the new call will have, on the QoS of both the new and the current clients, is assessed by sending test parcels and checking the systems. The choice of whether to acknowledge another call is made utilizing a novel math of QoS measurements, encourage by Warshall's calculation, which searches for a way with adequate QoS values that can oblige the new stream. The fundamental scientific standards and present trial results acquired by assessing the strategy in an expansive research center proving ground working the Self-Aware Cognitive Packet Network (CPN) convention

Enhancing QoS provisioning and granularity in next generation internet

Next Generation IP technology has the potential to prevail, both in the access and in the core networks, as we are moving towards a multi-service, multimedia and high-speed networking environment. Many new applications, including the multimedia applications, have been developed and deployed, and demand Quality of Service (QoS) support from the Internet, in addition to the current best effort service. Therefore, QoS provisioning techniques in the Internet to guarantee some specific QoS parameters are more a requirement than a desire. Due to the large amount of data flows and bandwidth demand, as well as the various QoS requirements, scalability and fine granularity in QoS provisioning are required. In this dissertation, the end-to-end QoS provisioning mechanisms are mainly studied, in order to provide scalable services with fine granularity to the users, so that both users and network service providers can achieve more benefits from the QoS provisioned in the network. To provide the end-to-end QoS guarantee, single-node QoS provisioning schemes have to be deployed at each router, and therefore, in this dissertation, such schemes are studied prior to the study of the end-to-end QoS provisioning mechanisms. Specifically, the effective sharing of the output bandwidth among the large amount of data flows is studied, so that fairness in the bandwidth allocation among the flows can be achieved in a scalable fashion. A dual-rate grouping architecture is proposed in this dissertation, in which the granularity in rate allocation can be enhanced, while the scalability of the one-rate grouping architecture is still maintained. It is demonstrated that the dual-rate grouping architecture approximates the ideal per-flow based PFQ architecture better than the one-rate grouping architecture, and provides better immunity capability. On the end-to-end QoS provisioning, a new Endpoint Admission Control scheme for Diffserv networks, referred to as Explicit Endpoint Admission Control (EEAC), is proposed, in which the admission control decision is made by the end hosts based on the end-to-end performance of the network. A novel concept, namely the service vector, is introduced, by which an end host can choose different services at different routers along its data path. Thus, the proposed service provisioning paradigm decouples the end-to-end QoS provisioning from the service provisioning at each router, and the end-to-end QoS granularity in the Diffserv networks can be enhanced, while the implementation complexity of the Diffserv model is maintained. Furthermore, several aspects of the implementation of the EEAC and service vector paradigm, referred to as EEAC-SV, in the Diffserv architecture are also investigated. The performance analysis and simulation results demonstrate that the proposed EEAC-SV scheme, not only increases the benefit to the service users, but also enhances the benefit to the network service provider in terms of network resource utilization. The study also indicates that the proposed EEAC-SV scheme can provide a compatible and friendly networking environment to the conventional TCP flows, and the scheme can be deployed in the current Internet in an incremental and gradual fashion

Throughput Analysis of End-to-End Measurement Based Admission Control in IP

This paper introduces approximate analytical models to evaluate the performance of end-to-end measurement based connection admission control (EMBAC) mechanisms, devised for the setup of real time flows over the Internet. These mechanisms rely on users probing the current congestion status of their required network path using a succession of probing packets. If the probing rate measured at the end receivers is greater than a certain threshold, users are allowed to switch to a phase of data exchange; otherwise they abort the call setup attempts. In conformance with the differentiated services framework, routers are oblivious to individual flows, and only need to give higher priority to data packets than to probing traffic. Despite the approximations introduced to make the analysis tractable, our model appears to be extremely accurate for a scenario of constant rate connections. Much less accurate, but useful as a possible starting point for future work, is the extension of the model to a scenario of variable rate connections. Simulation results are also presented in the paper to gain additional quantitative insights on the effectiveness of EMBAC to provide support for tight QoS requirement

Quality Of Service Enhancement In Ip Based Networks Using Diffserv

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2003Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2003Bu çalışmada, Diffserv mimarisi ile internet üzerinde servis kalitesi sağlama tartışılmıştır. Son on yılda IP tabanlı internette servis kalitesi sağlanamıyordu. İnternette bugün sağlanabilen tek servis ‘Best Effort (BE)’ adı verilen servistir. Yani, ağ, herhangi bir paketi hedefine ulaştırırken mümkün olan en verimli yolu kullanır ancak herhangi bir garanti ya da kaynak ayırımı yapmaz. Başka bir deyişle, trafik mümkün olduğu kadar hızlı ve herhangi bir zaman sınırı ya da miktar açısından garanti verilmeden işlenir. İnternetin ticari bir yapıya bürünmesiyle ‘Servis Kalitesi’ sağlanma ihtiyacı daha da artmıştır. Bu ihtiyaç farklı mimarilerin doğmasına yol açmıştır: IntServ ve DiffServ olmak üzere.Tez çalışmasında DiffServ mimarisi problem ve avantajlarıyla ele alınmıştır. Son bölümde ise NS2 ağ simulasyon yazılımı kullanılarak DiffServ implementasyonları yapılmış sonuçları karşılaştırmalı olarak verilmiştir.In this study improving Quality of Service (QoS) on the Internet with DiffServ architecture is discussed. Within the past decade, it is certainly not support for Quality of Service (QoS) over the IP-based ubiquitous Internet. The Internet as it stands today only support one service class called -Best-Effort (BE) Service. The network would make an earnest attempt to deliver packets to their destinations but with no guarantees and/or special resources allocated for any of the packets. With another words, traffic is processed as quickly as possible but there is no guarantee as to timeliness or actual delivery or even how much can be delivered (i.e. throughput). With the rapid transformation of the Internet into a commercial infrastructure, demands for Quality of Service (QoS) have rapidly developed. This need was resulted to different architectures: IntServ and DiffServ. In the study some DiffServ implementations are discussed with their problems and gains. At the last section with using NS2 simulation programming language some DiffServ implementations are given with the compared results.Yüksek LisansM.Sc

Queuing analysis and optimization techniques for energy efficiency in packet networks

Energy efficiency in all aspects of human life has become a major concern, due to its significant environmental impact as well as its economic importance. Information and Communication Technology (ICT) plays a dual role in this; not only does it constitute a major consumer itself (estimated 2-10% of the global consumption), but is also expected to enable global energy efficiency through new technologies tightly dependent on networks (smart grid, smart homes, cloud computing etc.). To this purpose, this work studies the problem of energy efficiency in wired networks. As this subject has recently become very active in the research community, there is parallel research towards several research directions. In this work, the problem is being examined from its foundations and a solid analytical approach is presented. Specifically, a network model based on G-network queuing theory is built, which can incorporate all the important parameters of power consumption together with traditional performance metrics and routing control capability. This generalized model can be applied for any network case to build optimization algorithms and estimate the performance of different policies and network designs. Composite optimization goals functions are proposed, comprising both power consumption and performance metrics. A gradient descent optimization algorithm that can run in O(N3) time complexity is built thereof. Using power consumption characteristics of current and future equipment, several case studies are presented and the optimization results are evaluated. Moreover, a faster gradient-descent based heuristic and a decentralized algorithm are proposed. Apart from the routing control analysis, the case of a harsher energy saving solution, namely turning o the networking equipment, is also experimentally explored. Applying a tradeoff study on a laboratory testbed, implementation challenges are identified and conclusions significant for future work are drawn. Finally, a novel admission control mechanism is proposed and experimentally evaluated, which can monitor and manage the power consumption and performance of a network.Open Acces

Quality of service assessment and analysis of wireless multimedia networks.

Recent years have witnessed a vast technological progress in the area of Quality of Service (QoS), mainly due to the emergence of multimedia networking and computing. QoS measurement and analysis have long been of interest to the networking research community. The major goals of this thesis are of two fold: Firstly, to investigate the effect of the QoS parameters on the overall QoS experienced by wireless networks. Secondly, to utilise the results in developing efficient mechanisms for intrusive and non-intrusive assessments of the performance of wireless ad hoc networks as well as the measurement of the available QoS for audio and videoconferencing applications over the IEEE 802.11 standard. To evaluate the network performance and the overall QoS of multimedia applications, new fuzzy logic and distance measure assessment approaches were developed taking into account the QoS parameters requirements of each application. The developed approaches essentially include measuring the main QoS parameters (delay, jitter and packet loss) and use them as input to the measurement systems, which combine them and produce an output that represents the instantaneous QoS. The devised approaches showed how the QoS can be measured without a need for complicated analytical mathematical models.In this study, several techniques were devised for estimating QoS. Firstly, a probe-based assessment method (active technique) was developed. In this method, special artificial monitoring packets were injected into the network. The overall QoS and its parameters were estimated by collecting statistics from these packets. It was possible to make reasonable inferences about the delay, throughput, packet losses and the overall average QoS using different probe rates. This technique showed some limitations for measuring the jitter. In addition, the rate of the monitoring packets played an essential role in the precision, level of resolution of estimated results and negatively impacted the network performance. Secondly, to overcome some of the drawbacks of the probing-based method, a new assessment technique was, subsequently, devised based on passive monitoring standard sampling methods. Unlike the active technique, the new method has the advantage of not adding an extra load to the network. In addition, it is not like the typical passive methods, which require the transfer and calculations of the whole captured data. Generally, all sampling schemes provided satisfactory measures of the overall QoS and its parameters and produced very acceptable bias and Relative Standard Error (RSE) result. Systematic sampling provided the most accurate estimates compared to the stratified and random approaches. In addition, after sample fraction of 2%, the estimated overall QoS bias from the actual QoS became constant and equal to -0.5% and RSE was less than 0.005 using both fuzzy and distance assessment systems. Thirdly, in order to overcome some negative aspects of inaccuracy and biasness caused by sampling techniques, a new scheme was proposed to correct these results to be closer to the actual traffic measurements. The new approach does not disturb the network performance (as in active methods), neither depends on the whole traffic (as in passive methods), nor bias the actual results (as in the standard sampling technique). Similarly, systematic sampling showed the best performance. Sample fractions, using the systematic sampling, greater than 2% gave an overall estimated QoS identical to the actual QoS because the obtained relative error was nearly constant and approximately close to zero using both assessment systems. The measured QoS can be used to optimise the received quality of the multimedia services along with the changing network conditions and to manage the utilisation of the network available resources especially for ad hoc networks. Overall, the findings of this study contribute to a method for drawing a realistic picture of the wireless multimedia networks QoS and provide a firm basis and useful insights on how to effectively design future QoS solutions

Gestão de recursos em redes com suporte de qualidade de serviço

Doutoramento em Engenharia ElectrotécnicaEsta Tese aborda a problemática da gestão de recursos em redes ATM (Asynchronous Transfer Mode) e IP (Internet Protocol) com suporte de QdS (Qualidade de Serviço). As tecnologias ATM e IP permitem, hoje em dia, integrar diferentes tipos de serviços numa mesma infra -estrutura de rede. No entanto, a diversidade dos serviços a suportar e dos seus requisitos, coloca grandes desafios ao nível da gestão de recursos, a qual se pretende o mais eficiente possível. A Tese está dividida em duas partes. A primeira parte da Tese foca a gestão de recursos em redes de acesso ATM e IP com suporte de QdS. É dada inicialmente uma perspectiva histórica da evolução das redes de acesso. No que diz respeito às redes de acesso ATM, são propostas estratégias de gestão de recursos com base em VPs (Virtual Paths) e são definidas metodologias de dimensionamento que têm em conta requisitos de QdS tanto ao nível da chamada como da célula. As estratégias de gestão de recursos consideradas permitem estabelecer compromissos entre a utilização de recursos e a carga de sinalização. No que diz respeito às redes de acesso IP, é proposta uma nova arquitectura de rede, que constitui uma evolução face às redes de acesso tradicionais ao permitir uma maior partilha de recursos. Esta arquitectura permite diferenciação de QdS e suporte de aplicações multimédia. Em particular é proposta uma solução que inclui o suporte integrado de tecnologias recentemente introduzidas para iniciar e configurar sessões multimédia, gerir as políticas de QdS incluindo as funcionalidades de AAA (Authentication, Authorization and Accounting), e reservar recursos. Na segunda parte da Tese é feita uma abordagem de dois mecanismos para controle de admissão de fluxos escaláveis: mecanismos de probing e mecanismos baseados em agregação de reservas individuais. Ambos os mecanismos permitem que a gestão de recursos seja feita sem necessidade de manutenção do estado dos fluxos activos em cada elemento de rede. O mecanismo de probing estima o nível de QdS da rede, através da inserção de fluxos de teste, por forma a decidir se um novo fluxo pode ou não ser aceite. É proposto um novo mecanismo de probing, denominado de ?-probing, que permite minimizar o problema do roubo de recursos que afecta o probing simples quando este é utilizado em sistemas com múltiplas classes de serviço. São desenvolvidos modelos analíticos e são efectuados estudos de simulação para analisar o problema do roubo de recursos e os factores que influenciam a estimativa do rácio de perdas efectuada pelos fluxos de probing e de ?-probing. Verificou-se que o mecanismo de ?-probing permite obter simultaneamente uma utilização elevada dos recursos e a diferenciação dos serviços sem roubo de recursos. Os resultados obtidos com este mecanismo foram também validados através do desenvolvimento de um protótipo laboratorial. No mecanismo baseado em agregação de reservas individuais, os elementos do núcleo da rede mantêm apenas o estado de agregados de fluxos (e não de fluxos individuais), sendo a largura de banda dos agregados ajustada de forma dinâmica. São desenvolvidos modelos analíticos e são efectuados estudos de simulação para analisar o compromisso entre a carga de sinalização e a utilização de recursos. Estes estudos mostram que a hierarquização da rede, ou seja, a sua divisão em áreas mais pequenas, e a configuração de agregados entre os routers fronteira das áreas, por oposição a agregados extremo-a-extremo entre os routers fronteira do domínio, permitem atingir uma utilização de recursos próxima da utilização com sinalização fluxo -a-fluxo, mas com uma carga de sinalização significativamente inferior.This Thesis addresses the problem of resource management in ATM (Asynchronous Transfer Mode) and IP (Internet Protocol) networks with QoS (Quality of Service) support. ATM and IP technologies allow, nowadays, the integration of different types of services in the same network infrastructure. However, the variety of services and their requirements, involve big challenges at the resource management level, which needs to be as efficient as possible. This Thesis is divided in two parts. The first part of the Thesis addresses the resource management of ATM and IP access networks with QoS support. It is presented an historical perspective of the access networks evolution. In terms of ATM access networks, resource management strategies based on VPs (Virtual Paths) are proposed, and dimensioning methodologies are defined, which take into account the QoS requirements at the call and cell level. The considered resource management strategies allow the establishment of trade-offs between the resource utilization and the signaling load. In terms of IP access networks, it is proposed a new network architecture that represents an evolution of the legacy access networks, allowing a larger resource sharing. This architecture allows QoS differentiation and support for multimedia applications. More specifically, it is proposed a solution that includes the integrated support of recently introduced technologies to establish and configure multimedia sessions, manage the QoS policies including AAA (Authentication, Authorization and Accounting) functions, and reserve network resources. In the second part of the Thesis, two scalable call admission control mechanisms are addressed: probing mechanisms and mechanisms based on the aggregation of individual reservations. Both mechanisms allow resource management without the maintenance of the per-flow state in each network element. The probing mechanism estimates the network QoS level, through the insertion of probe flows, to decide if a new flow can be accepted or not. A new probing mechanism is proposed, denoted by ?-probing, which minimizes the resource stealing problem that exists in the simple probing mechanism when it is applied to a system with multiple service classes. Analytical models are developed and simulation studies are performed to analyze the resource stealing problem and to determine the influencing factors on the estimation of the loss ratio performed by the probing and ?-probing flows. The ?-probing mechanism obtains, simultaneously, a high resource utilization and service differentiation without resource stealing. The results obtained with this mechanism were also validated through the development of a probing test-bed. In the mechanism based on the aggregation of individual reservations, the core network elements only need to maintain the state of the flows’ aggregate (instead of individual flows), and the aggregates’ bandwidth is dynamically adjusted. Analytical models are defined and simulation studies are performed to analyze the trade -off between signaling load and resource utilization. These studies show that the hierarquization of the network, that is, its partition in smaller areas, and the configuration of aggregates between area border routers, as opposed to end-to - end aggregates between domain border routers, reaches an utilization close to the one of per-flow signaling with a signaling load significantly smaller