16 research outputs found
User-Centric Quality of Service Provisioning in IP Networks
The Internet has become the preferred transport medium for almost every type of communication, continuing to grow, both in terms of the number of users and delivered services. Efforts have been made to ensure that time sensitive applications receive sufficient resources and subsequently receive an acceptable Quality of Service (QoS). However, typical Internet users no longer use a single service at a given point in time, as they are instead engaged in a multimedia-rich experience, comprising of many different concurrent services. Given the scalability problems raised by the diversity of the users and traffic, in conjunction with their increasing expectations, the task of QoS provisioning can no longer be approached from the perspective of providing priority to specific traffic types over coexisting services; either through explicit resource reservation, or traffic classification using static policies, as is the case with the current approach to QoS provisioning, Differentiated Services (Diffserv). This current use of static resource allocation and traffic shaping methods reveals a distinct lack of synergy between current QoS practices and user activities, thus highlighting a need for a QoS solution reflecting the user services.
The aim of this thesis is to investigate and propose a novel QoS architecture, which considers the activities of the user and manages resources from a user-centric perspective. The research begins with a comprehensive examination of existing QoS technologies and mechanisms, arguing that current QoS practises are too static in their configuration and typically give priority to specific individual services rather than considering the user experience. The analysis also reveals the potential threat that unresponsive application traffic presents to coexisting Internet services and QoS efforts, and introduces the requirement for a balance between application QoS and fairness.
This thesis proposes a novel architecture, the Congestion Aware Packet Scheduler (CAPS), which manages and controls traffic at the point of service aggregation, in order to optimise the overall QoS of the user experience. The CAPS architecture, in contrast to traditional QoS alternatives, places no predetermined precedence on a specific traffic; instead, it adapts QoS policies to each individual’s Internet traffic profile and dynamically controls the ratio of user services to maintain an optimised QoS experience. The rationale behind this approach was to enable a QoS optimised experience to each Internet user and not just those using preferred services. Furthermore, unresponsive bandwidth intensive applications, such as Peer-to-Peer, are managed fairly while minimising their impact on coexisting services.
The CAPS architecture has been validated through extensive simulations with the topologies used replicating the complexity and scale of real-network ISP infrastructures. The results show that for a number of different user-traffic profiles, the proposed approach achieves an improved aggregate QoS for each user when compared with Best effort Internet, Traditional Diffserv and Weighted-RED configurations. Furthermore, the results demonstrate that the proposed architecture not only provides an optimised QoS to the user, irrespective of their traffic profile, but through the avoidance of static resource allocation, can adapt with the Internet user as their use of services change.France Teleco
Toward a versatile transport protocol
Les travaux présentés dans cette thèse ont pour but d'améliorer la couche transport de l'architecture réseau de l'OSI. La couche transport est de nos jour dominée par l'utilisation de TCP et son contrôle de congestion. Récemment de nouveaux mécanismes de contrôle de congestion ont été proposés. Parmi eux TCP Friendly Rate Control (TFRC) semble être le plus abouti. Cependant, tout comme TCP, ce mécanisme ne prend pas en compte ni les évolutions du réseau ni les nouveaux besoins des applications. La première contribution de cette thèse consiste en une spécialisation de TFRC afin d'obtenir un protocole de transport avisé de la Qualité de Service (QdS) spécialement défini pour des réseaux à QdS offrant une garantie de bande passante. Ce protocole combine un mécanisme de contrôle de congestion orienté QdS qui prend en compte la réservation de bande passante au niveau réseau, avec un service de fiabilité totale afin de proposer un service similaire à TCP. Le résultat de cette composition constitue le premier protocole de transport adapté à des réseau à garantie de bande passante. En même temps que cette expansion de service au niveau réseau, de nouvelles technologies ont été proposées et déployées au niveau physique. Ces nouvelles technologies sont caractérisées par leur affranchissement de support filaire et la mobilité des systèmes terminaux. De plus, elles sont généralement déployées sur des entités où la puissance de calcul et la disponibilité mémoire sont inférieures à celles des ordinateurs personnels. La deuxième contribution de cette thèse est la proposition d'une adaptation de TFRC à ces entités via la proposition d'une version allégée du récepteur. Cette version a été implémentée, évaluée quantitativement et ses nombreux avantages et contributions ont été démontrés par rapport à TFRC. Enfin, nous proposons une optimisation des implémentations actuelles de TFRC. Cette optimisation propose tout d'abord un nouvel algorithme pour l'initialisation du récepteur basé sur l'utilisation de l'algorithme de Newton. Nous proposons aussi l'introduction d'un outil nous permettant d'étudier plus en détails la manière dont est calculé le taux de perte du côté récepteur. ABSTRACT : This thesis presents three main contributions that aim to improve the transport layer of the current networking architecture. The transport layer is nowadays overruled by the use of TCP and its congestion control. Recently new congestion control mechanisms have been proposed. Among them, TCP Friendly Rate Control (TFRC) appears to be one of the most complete. Nevertheless this congestion control mechanism, as TCP, does not take into account either the evolution of the network in terms of Quality of Service and mobility or the evolution of the applications. The first contribution of this thesis is a specialisation TFRC congestion control to propose a QoS-aware Transport Protocol specifically designed to operate over QoS-enabled networks with bandwidth guarantee mechanisms. This protocol combines a QoS-aware congestion control, which takes into account networklevel bandwidth reservations, with full reliability in order mechanism to provide a transport service similar to TCP. As a result, we obtain the guaranteed throughput at the application level where TCP fails. This protocol is the first transport protocol compliant with bandwidth guaranteed networks. At the same time the set of network services expands, new technologies have been proposed and deployed at the physical layer. These new technologies are mainly characterised by communications done without wire constraint and the mobility of the end-systems. Furthermore, these technologies are usually deployed on entities where the CPU power and memory storage are limited. The second contribution of this thesis is therefore to propose an adaptation of TFRC to these entities. This is accomplished with the proposition of a new sender-based version of TFRC. This version has been implemented, evaluated and its numerous contributions and advantages compare to usual TFRC version have been demonstrated. Finally, we proposed an optimisation of actual implementations of TFRC. This optimisation first consists in the proposition of an algorithm based on a numerical analysis of the equation used in TFRC and the use of the Newton's algorithm. We furthermore give a first step, with the introduction of a new framework for TFRC, in order to better understand TFRC behaviour and to optimise the computation of the packet loss rate according to loss probability distribution
Network emulation focusing on QoS-Oriented satellite communication
This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication
Congestion Control for Streaming Media
The Internet has assumed the role of the underlying communication network for applications such as file transfer, electronic mail, Web browsing and multimedia streaming. Multimedia streaming, in particular, is growing with the growth in power and connectivity of today\u27s computers. These Internet applications have a variety of network service requirements and traffic characteristics, which presents new challenges to the single best-effort service of today\u27s Internet. TCP, the de facto Internet transport protocol, has been successful in satisfying the needs of traditional Internet applications, but fails to satisfy the increasingly popular delay sensitive multimedia applications. Streaming applications often use UDP without a proper congestion avoidance mechanisms, threatening the well-being of the Internet. This dissertation presents an IP router traffic management mechanism, referred to as Crimson, that can be seamlessly deployed in the current Internet to protect well-behaving traffic from misbehaving traffic and support Quality of Service (QoS) requirements of delay sensitive multimedia applications as well as traditional Internet applications. In addition, as a means to enhance Internet support for multimedia streaming, this dissertation report presents design and evaluation of a TCP-Friendly and streaming-friendly transport protocol called the Multimedia Transport Protocol (MTP). Through a simulation study this report shows the Crimson network efficiently handles network congestion and minimizes queuing delay while providing affordable fairness protection from misbehaving flows over a wide range of traffic conditions. In addition, our results show that MTP offers streaming performance comparable to that provided by UDP, while doing so under a TCP-Friendly rate
Throughput and Delay on the Packet Switched Internet
The Internet has become a vital and essential part of modern everyday life. Services delivered by the Internet are used by people across the planet every moment of every day of the year. The Internet has proven a positive force for good improving the lives of billions of people worldwide. The power of the Internet to deliver this positive good to humanity relies on its ability to deliver life improving services. In my doctorate work culminating in this dissertation I have striven to sustain and increase the Internet's ability to deliver these services and to have a positive good effect upon humanity.The overarching purpose of this dissertation is to improve the Internet's ability to deliver life improving services. I have further divided this purpose into two goals. To improve the ability of applications operating in challenging network conditions to gain their fair share of the bandwidth resources and to reduce the delay with which these services are delivered. Every service delivered by the Internet consists of Internet objects that are delivered through communication paths across the Internet. The delivery of these objects is defined by the two characteristics; Throughput and delay. Throughput determines how much of an object can be delivered over a period of time and delay determines how long it takes to deliver an object.These two characteristics determine the Internet's ability to deliver objects across communication paths. Improving these two characteristics (bandwidth and delay) increase the ability of the Internet to deliver objects and thus improve the Internet's capability to deliver life improving services. To accomplish this goal I present projects along three areas of effort. These three areas of effort are: (1) Increase the ability of applications operating in challenging conditions to achieve their fair share of bandwidth. (2) Synthesize knowledge required to address the effort to reduce delay. (3) Develop protocols that reduce delay encountered in the communications paths of the Internet.In this dissertation I present projects along these three areas of effort that accomplish the two goals (increase bandwidth and reduce delay) to achieve the purpose of improving the Internet's ability to deliver essential and life improving services. These projects and their organization into areas of effort, goals and purpose are my contributions to the networking sciences
QoS-aware Mobility Management in IP-based Communication Networks
Der allgegenwärtige Zugang zu Informationen, jederzeit und überall, ist ein
wichtiges Merkmal künftiger All-IP-Mobilfunktnetze, die verschiedene
Systeme miteinander verbinden, dabei dynamischer und flexibler sein
werden. Der Einsatz dieser Netze erfordert es jedoch, viele
Herausforderungen zu überwinden. Eine der wichtigsten im Rahmen dieser
Arbeit, ist die Frage, wie Quality of Service (QoS) Eigenschaften in
solchen hoch dynamischen, mobilen Umgebungen zu garantieren sind. Bekanntermaßen beeinflusst die Mobilität von Mobilknoten (MN) die Dienstgüte in mobilen Netzen, da QoS-Parameters für
die Ende-zu-Ende-Kommunikation vereinbart werden. Daher müssen Lösungen
entwickelt werden, die nahtlose Mobilität, bei gleichzeitigen QoS-Garantien
nach Handoffs, unterstützen. Diese Herausforderung ist das Hauptziel der
vorliegenden Dissertation, die einen umfassenden Überblick über die
bestehenden Mobilitäts- und QoS-Managment-Lösungen in IP-basierten Netzen
liefert, gefolgt von einem Einblick in Methoden zur Kopplung von
Mobilitätsmanagement und QoS-Lösungen. Nach Betrachtung der Vor- und
Nachteile bestehender Ansätze, kommt die Dissertation zu dem Schluss, dass
hybride Strategien vielversprechend sind und zu praktikablen Lösungen
weiterentwickelt werden können, die sowohl Mobilitäts- als auch
QoS-Anforderungen auf effiziente Weise,in allen zukünftigen IP-Mobilfunknetzen erfüllen können. Auf dieser Grundlage schlägt die Dissertation ein neues Hybrid-Protokoll, genannt
"QoS-aware Mobile IP Fast Authentication Protocol" (QoMIFA), vor. Unser
Vorschlag integriert MIFA als Mobilitäts-Management-Protokoll mit RSVP als
QoS Reservierungsprotokoll. MI-FA wird aufgrund seiner Fähigkeit zu
schnellen, sicheren und robusten Handoffs gewählt. RSVP hingegen dient als
Standardlösung zur Bereitstellung von QoS in bestehenden IP-basierten
Netzen. Unter Einhaltung der Hybrid-Architektur wird RSVP um ein neues
Objekt, genannt "Mobility Object" erweitert, welches
MIFA-Kontrollnachrichten kapselt. Nach der Spezifikation des neuen
Vorschlags, bewertet die Dissertation auch seine Leistung im Vergleich zu
dem bekannten "Simple QoS Signaling Protocol" (Simple QoS), mittels
Simulationsstudien, modelliert mit dem "Network Simluator 2" (NS2). In der
Auswertung werden der Einflusses der Netzwerklast und der Geschwindigkeit
des Mobilknotens untersucht. Die hierzu verwendeten Leistungsparameter
umfassen die Ressourcen-Reservierungs-Latenz, die Anzahl verlorener Pakete
pro Handoff, die Anzahl der, vor Abschluss der Reservierung, mit
Best-Effort-Eigenschaften übertragenen Pakete pro Handoff und die
Wahrscheinlichkeit von Verbindungsabbrüchen. Unsere mittels Simulation
erzielten Ergebnisse zeigen, dass QoMIFA schnelle und nahtlose Handoffs mit
schneller Ressourcenreservierung nach Handoffs kombinieren kann. Unter
Berücksichtigung des Einflusses der Netzwerklast, ist nachweisbar, dass
QoMIFA eine besser Leistung als Simple QoS in allen untersuchten Szenarien
mit geringer, mittlerer und hoher Last erreicht. Bei Betrachtung des
Einflusses der Bewegungsgeschwindigkeit des Mobilknotens auf die Leistung,
lassen sich unter beiden Protokollen Ping-Pong-Effekte beobachten, welche
zu höheren Ressourcen-Reservierungs-Latenzen, mehr verlorenen Paketen und
mehr Best-Effort-Paketen pro Handoff bei geringeren Geschwindigkeiten
führen. Der stärkste Einfluss dieser Pinp-Pong-Effekte ist jeweils bei 3
km/h zu beobachten. Allerdings verhält sich QoMIFA unter allen untersuchten
Bewegungsgeschwindigkeiten besser als Simple QoS und kann Mobilknoten auch
bei hohen Geschwindigkeiten bedienen. In Anschluss an die
simulationsgestützte Evaluierung, schätzt die Dissertation die
Signalisierungskosten beider Protokolle unter Betrachtung der Kosten für
Ortslokalise-rung und Paketzustellung. Im Ergebnis erreicht QoMIFA die
zuvor genannten Leistungsverbesserungen auf Kosten von größeren
Ortslokalisierungskosten und leicht höherer Paketzustellungskosten.Ubiquitous access to information anywhere, anytime and anyhow is an
important feature of future all-IP mobile communication networks, which
will interconnect various systems and be more dynamic and flexible. The
deployment of these networks, however, requires overcoming many challenges.
One of the main challenges of interest for this work is how to provide
Qual-ity of Service (QoS) guarantees in such highly dynamic mobile
environments.As known, mobility of Mobile Nodes (MNs) affects the QoS in
mobile networks since QoS parameters are made for end-to-end
communications. Therefore, it is a challenge to develop new solutions
capable of supporting seamless mobility while simultaneously providing QoS
guarantees after handoffs. Addressing this challenge is the main objective
of this dissertation, which provides a comprehensive overview of mobility
management solutions and QoS mech-anisms in IP-based networks followed by
an insight into how mobility management and QoS solutions can be coupled
with each other. Following the highlight of the state of art along with the
pros and cons of existing approaches, the dissertation concludes that
hybrid strategies are promising and can be further developed to achieve
solutions that are capable of simultaneous-ly supporting mobility and QoS,
simple from the implementation point of view, efficient and applicable to
future all-IP mobile communication networks.Based on this, the dissertation
proposes a new hybrid proposal named QoS-aware Mobile IP Fast
Authentication Protocol (QoMIFA). Our proposal integrates MIFA as a
mobility man-agement protocol with RSVP as a QoS reservation protocol. MIFA
is selected due to its capa-bility of the provision of fast, secure and
robust handoffs, while RSVP is chosen because it presents the standard
solution used to support QoS in existing IP-based networks. The hybrid
architecture is retained by introducing a new object, called “mobility
object”, to RSVP in or-der to encapsulate MIFA control messages.Following
the specification of the new proposal, the dissertation also evaluates its
perfor-mance compared to the well-known Simple QoS signaling protocol
(Simple QoS) by means of simulation studies modeled using the Network
Simulator 2 (NS2). The evaluation compris-es the investigation of the
impact of network load and MN speed. The performance measures we are
interested in studying comprise the resource reservation latency, number of
dropped packets per handoff, number of packets sent as best-effort per
handoff until the reservation is accomplished and probability of dropping
sessions. Our simulation results show that QoMIFA is capable of achieving
fast and smooth handoffs in addition to its capability of quickly
re-serving resources after handoffs. Considering the impact of network
load, QoMIFA outper-forms Simple QoS in all studied scenarios (low- ,
middle- and high-loaded scenarios). With respect to the impact of MN speed,
it can be observed that the impact of ping-pong effects is seen with both
protocols and results in higher resource reservation latency, more dropped
packets per handoff and more best-effort packets per handoff at low speeds
than at higher ones. The worst impact of ping-pong effects is seen at a
speed of 3 km/h when employing QoMIFA and Simple QoS, respectively.
However, QoMIFA remains performing significantly better than Simple QoS
under all studied MN speeds and can even properly serve MNs mov-ing at high
speeds.Following the simulative evaluation, the dissertation estimates the
signaling cost of both stud-ied protocols with respect to the location
update and packet delivery cost. Our results show that QoMIFA achieves the
above mentioned performance improvements at the cost of greater location
update cost and slightly higher packet delivery cost than Simple QoS
Real-time data flow models and congestion management for wire and wireless IP networks
Includes abstract.Includes bibliographical references (leaves 103-111).In video streaming, network congestion compromises the video throughput performance and impairs its perceptual quality and may interrupt the display. Congestion control may take the form of rate adjustment through mechanisms by attempt to minimize the probability of congestion by adjusting the rate of the streaming video to match the available capacity of the network. This can be achieved either by adapting the quantization parameter of the video encoder or by varying the rate through a scalable video technique. This thesis proposes a congestion control protocol for streaming video where an interaction between the video source and the receiver is essential to monitor the network state. The protocol consists of adjusting the video transmission rate at the encoder whenever a change in the network conditions is observed and reported back to the sender
Re-feedback: freedom with accountability for causing congestion in a connectionless internetwork
This dissertation concerns adding resource accountability to a simplex internetwork such as the Internet,
with only necessary but sufficient constraint on freedom. That is, both freedom for applications to evolve
new innovative behaviours while still responding responsibly to congestion; and freedom for network
providers to structure their pricing in any way, including flat pricing.
The big idea on which the research is built is a novel feedback arrangement termed ‘re-feedback’.
A general form is defined, as well as a specific proposal (re-ECN) to alter the Internet protocol so that
self-contained datagrams carry a metric of expected downstream congestion.
Congestion is chosen because of its central economic role as the marginal cost of network usage.
The aim is to ensure Internet resource allocation can be controlled either by local policies or by market
selection (or indeed local lack of any control).
The current Internet architecture is designed to only reveal path congestion to end-points, not networks.
The collective actions of self-interested consumers and providers should drive Internet resource
allocations towards maximisation of total social welfare. But without visibility of a cost-metric, network
operators are violating the architecture to improve their customer’s experience. The resulting fight
against the architecture is destroying the Internet’s simplicity and ability to evolve.
Although accountability with freedom is the goal, the focus is the congestion metric, and whether
an incentive system is possible that assures its integrity as it is passed between parties around the system,
despite proposed attacks motivated by self-interest and malice.
This dissertation defines the protocol and canonical examples of accountability mechanisms. Designs
are all derived from carefully motivated principles. The resulting system is evaluated by analysis
and simulation against the constraints and principles originally set. The mechanisms are proven to be
agnostic to specific transport behaviours, but they could not be made flow-ID-oblivious
MOBILITY SUPPORT ARCHITECTURES FOR NEXT-GENERATION WIRELESS NETWORKS
With the convergence of the wireless networks and the Internet and the booming
demand for multimedia applications, the next-generation (beyond the third generation, or
B3G) wireless systems are expected to be all IP-based and provide real-time and non-real-time
mobile services anywhere and anytime. Powerful and efficient mobility support is
thus the key enabler to fulfil such an attractive vision by supporting various mobility
scenarios. This thesis contributes to this interesting while challenging topic.
After a literature review on mobility support architectures and protocols, the thesis
starts presenting our contributions with a generic multi-layer mobility support framework,
which provides a general approach to meet the challenges of handling comprehensive
mobility issues. The cross-layer design methodology is introduced to coordinate the
protocol layers for optimised system design. Particularly, a flexible and efficient cross-layer
signalling scheme is proposed for interlayer interactions. The proposed generic
framework is then narrowed down with several fundamental building blocks identified to
be focused on as follows.
As widely adopted, we assume that the IP-based access networks are organised into
administrative domains, which are inter-connected through a global IP-based wired core
network. For a mobile user who roams from one domain to another, macro (inter-domain)
mobility management should be in place for global location tracking and effective handoff
support for both real-time and non-real-lime applications. Mobile IP (MIP) and the Session
Initiation Protocol (SIP) are being adopted as the two dominant standard-based macro-mobility
architectures, each of which has mobility entities and messages in its own right.
The work explores the joint optimisations and interactions of MIP and SIP when utilising
the complementary power of both protocols. Two distinctive integrated MIP-SIP
architectures are designed and evaluated, compared with their hybrid alternatives and other
approaches. The overall analytical and simulation results shown significant performance
improvements in terms of cost-efficiency, among other metrics.
Subsequently, for the micro (intra-domain) mobility scenario where a mobile user
moves across IP subnets within a domain, a micro mobility management architecture is
needed to support fast handoffs and constrain signalling messaging loads incurred by intra-domain
movements within the domain. The Hierarchical MIPv6 (HMIPv6) and the Fast
Handovers for MIPv6 (FMIPv6) protocols are selected to fulfil the design requirements.
The work proposes enhancements to these protocols and combines them in an optimised
way. resulting in notably improved performances in contrast to a number of alternative
approaches