14 research outputs found
Multihoming with ILNP in FreeBSD
Multihoming allows nodes to be multiply connected to the network. It forms the
basis of features which can improve network responsiveness and robustness; e.g. load
balancing and fail-over, which can be considered as a choice between network locations.
However, IP today assumes that IP addresses specify both network location
and node identity. Therefore, these features must be implemented at routers.
This dissertation considers an alternative based on the multihoming approach of
the Identifier Locator Network Protocol (ILNP). ILNP is one of many proposals for
a split between network location and node identity. However, unlike other proposals,
ILNP removes the use of IP addresses as they are used today. To date, ILNP has not
been implemented within an operating system stack.
I produce the first implementation of ILNP in FreeBSD, based on a superset of
IPv6 – ILNPv6 – and demonstrate a key feature of ILNP: multihoming as a first
class function of the operating system, rather than being implemented as a routing
function as it is today.
To evaluate the multihoming capability, I demonstrate one important application
of multihoming – load distribution – at three levels of network hierarchy including
individual hosts, a singleton Site Border Router (SBR), and a novel, dynamically instantiated,
distributed SBR (dSBR). For each level, I present empirical results from a
hardware testbed; metrics include latency, throughput, loss and reordering. I compare
performance with unmodified IPv6 and NPTv6. Finally, I evaluate the feasibility of
dSBR-ILNPv6 as an alternative to existing multihoming approaches, based on measurements
of the dSBR’s responsiveness to changes in site connectivity.
We find that multihoming can be implemented by individual hosts and/or SBRs,
without requiring additional routing state as is the case today, and without any
significant additional load or overhead compared to unicast IPv6
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QOE-AWARE CONTENT DISTRIBUTION SYSTEMS FOR ADAPTIVE BITRATE VIDEO STREAMING
A prodigious increase in video streaming content along with a simultaneous rise in end system capabilities has led to the proliferation of adaptive bit rate video streaming users in the Internet. Today, video streaming services range from Video-on-Demand services like traditional IP TV to more recent technologies such as immersive 3D experiences for live sports events. In order to meet the demands of these services, the multimedia and networking research community continues to strive toward efficiently delivering high quality content across the Internet while also trying to minimize content storage and delivery costs.
The introduction of flexible and adaptable technologies such as compute and storage clouds, Network Function Virtualization and Software Defined Networking continue to fuel content provider revenue. Today, content providers such as Google and Facebook build their own Software-Defined WANs to efficiently serve millions of users worldwide, while NetFlix partners with ISPs such as ATT (using OpenConnect) and cloud providers such as Amazon EC2 to serve their content and manage the delivery of several petabytes of high-quality video content for millions of subscribers at a global scale, respectively. In recent years, the unprecedented growth of video traffic in the Internet has seen several innovative systems such as Software Defined Networks and Information Centric Networks as well as inventive protocols such as QUIC, in an effort to keep up with the effects of this remarkable growth. While most existing systems continue to sub-optimally satisfy user requirements, future video streaming systems will require optimal management of storage and bandwidth resources that are several orders of magnitude larger than what is implemented today. Moreover, Quality-of-Experience metrics are becoming increasingly fine-grained in order to accurately quantify diverse content and consumer needs.
In this dissertation, we design and investigate innovative adaptive bit rate video streaming systems and analyze the implications of recent technologies on traditional streaming approaches using real-world experimentation methods. We provide useful insights for current and future content distribution network administrators to tackle Quality-of-Experience dilemmas and serve high quality video content to several users at a global scale. In order to show how Quality-of-Experience can benefit from core network architectural modifications, we design and evaluate prototypes for video streaming in Information Centric Networks and Software-Defined Networks. We also present a real-world, in-depth analysis of adaptive bitrate video streaming over protocols such as QUIC and MPQUIC to show how end-to-end protocol innovation can contribute to substantial Quality-of-Experience benefits for adaptive bit rate video streaming systems. We investigate a cross-layer approach based on QUIC and observe that application layer-based information can be successfully used to determine transport layer parameters for ABR streaming applications
Network emulation focusing on QoS-Oriented satellite communication
This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication
Conservation de l'énergie sur des environnements de réseaux d'accès radio hétérogènes : vers des réseaux auto-organisants et verts
Since the last decades, environmental issues are becoming among the major concerns for most human activities, including the Information and Communication Technologies sector. This will surely influence upcoming networking technologies, architectures and usage practices. New approaches and methodologies are required in order to evaluate and to reduce the Carbon Footprint toward what is commonly denoted as Green Networks. Within the ICT sector, the main efforts are related to energy saving techniques. These efforts started in early stages within wireless technologies, mainly because of energy limitations on mobile devices such as mobile phones and wireless sensors. Additionally, because of health considerations, standardization bodies and government had set stringent policies and limits on electromagnetic radiation levels that can be emitted by radio stations. For these reasons, many academic and industrial research and development activities had led to a number of relatively energy efficient solutions. In this thesis, we consider energy efficiency in the context of Heterogeneous Wireless Access Networks. These are composed of multi-standards wireless network solutions, with non uniform topologies and cell sizes and Multi-Modal mobile terminals able to manage simultaneously different connections. The main contributions of our studies include the proposal of new optimization solutions regarding user association and scheduling techniques at both flow and packet levels for multi-homed mobile terminals. An overall context-based solution is also proposed in order to provide end-to-end energy efficient networking solutionsLa préservation de l’environnement et des ressources naturelles pour les prochaines générations est aujourd’hui considérée comme un des axes les plus prioritaires dans presque tous les secteurs économiques. Le secteur des Technologies de l’Information et de la Communication est loin d’être épargné de cette tendance écologique. Nous considérons dans cette thèse la problématique de la conservation d’énergie dans le contexte technologique actuel caractérisé par: •La coexistence d’une multitude de technologies d’accès sans fil offrant un environnement riche et dynamique • Des terminaux mobiles multimodaux • Limitations persistantes des sources d’énergie sur les terminaux mobiles. Dans ce contexte très riche, les possibilités offertes aux usagers sont à double tranchant. D’un côté, elles peuvent très bien améliorer la QoS en offrant toujours la meilleure connectivité en fonction du contexte de l’utilisateur. D’un autre côté, et sans une bonne optimisation de la consommation d’énergie sur le terminal, la disponibilité de celui-ci peut vite diminuer et donc faire baisser la QoE à cause de l’énergie nécessaire pour gérer plusieurs interfaces radio en parallèle. Nous considérons essentiellement les liens entre les stations de base (ou les point d’accès) et les terminaux mobiles. Notre objectif étant d’analyser la consommation d’énergie sur ces liens pour ensuite proposer des contributions permettant de mieux la maitriser. Nous focalisons essentiellement sur l’exploitation des multiples interfaces et du multi-flux pour étudier, analyser et proposer des solutions dynamiques et adaptatives d’ordonnancement, de sélection et de gestion d’interfaces minimisant la consommation d’énergi
Network Virtualization Over Elastic Optical Networks: A Survey of Allocation Algorithms
Network virtualization has emerged as a paradigm for cloud computing services by providing key functionalities such as abstraction of network resources kept hidden to the cloud service user, isolation of different cloud computing applications, flexibility in terms of resources granularity, and on‐demand setup/teardown of service. In parallel, flex‐grid (also known as elastic) optical networks have become an alternative to deal with the constant traffic growth. These advances have triggered research on network virtualization over flex‐grid optical networks. Effort has been focused on the design of flexible and virtualized devices, on the definition of network architectures and on virtual network allocation algorithms. In this chapter, a survey on the virtual network allocation algorithms over flexible‐grid networks is presented. Proposals are classified according to a taxonomy made of three main categories: performance metrics, operation conditions and the type of service offered to users. Based on such classification, this work also identifies open research areas as multi‐objective optimization approaches, distributed architectures, meta‐heuristics, reconfiguration and protection mechanisms for virtual networks over elastic optical networks
Resource management in future mobile networks: from millimetre-wave backhauls to airborne access networks
The next generation of mobile networks will connect vast numbers of devices and
support services with diverse requirements. Enabling technologies such as millimetre-wave
(mm-wave) backhauling and network slicing allow for increased wireless capacities
and logical partitioning of physical deployments, yet introduce a number of
challenges. These include among others the precise and rapid allocation of network
resources among applications, elucidating the interactions between new mobile networking
technology and widely used protocols, and the agile control of mobile infrastructure,
to provide users with reliable wireless connectivity in extreme scenarios.
This thesis presents several original contributions that address these challenges.
In particular, I will first describe the design and evaluation of an airtime allocation
and scheduling mechanism devised specifically for mm-wave backhauls, explicitly addressing
inter-flow fairness and capturing the unique characteristics of mm-wave communications.
Simulation results will demonstrate 5x throughput gains and a 5-fold
improvement in fairness over recent mm-wave scheduling solutions. Second, I will
introduce a utility optimisation framework targeting virtually sliced mm-wave backhauls
that are shared by a number of applications with distinct requirements. Based
on this framework, I will present a deep learning solution that can be trained within
minutes, following which it computes rate allocations that match those obtained with
state-of-the-art global optimisation algorithms. The proposed solution outperforms a
baseline greedy approach by up to 62%, in terms of network utility, while running
orders of magnitude faster. Third, the thesis investigates the behaviour of the Transport
Control Protocol (TCP) in Long-Term Evolution (LTE) networks and discusses
the implications of employing Radio Link Control (RLC) acknowledgements under
different link qualities, on the performance of transport protocols. Fourth, I will introduce
a reinforcement learning approach to optimising the performance of airborne cellular
networks serving users in emergency settings, demonstrating rapid convergence
(approx. 2.5 hours on a desktop machine) and a 5dB improvement of the median
Signal-to-Noise-plus-Interference-Ratio (SINR) perceived by users, over a heuristic
based benchmark solution. Finally, the thesis discusses promising future research directions
that follow from the results obtained throughout this PhD project
Enhancing programmability for adaptive resource management in next generation data centre networks
Recently, Data Centre (DC) infrastructures have been growing rapidly to support a wide range of emerging services, and provide the underlying connectivity and compute resources that facilitate the "*-as-a-Service" model. This has led to the deployment of a multitude of services multiplexed over few, very large-scale centralised infrastructures. In order to cope with the ebb and flow of users, services and traffic, infrastructures have been provisioned for peak-demand resulting in the average utilisation of resources to be low. This overprovisionning has been further motivated by the complexity in predicting traffic demands over diverse timescales and the stringent economic impact of outages. At the same time, the emergence of Software Defined Networking (SDN), is offering new means to monitor and manage the network infrastructure to address this underutilisation.
This dissertation aims to show how measurement-based resource management can improve performance and resource utilisation by adaptively tuning the infrastructure to the changing operating conditions. To achieve this dynamicity, the infrastructure must be able to centrally monitor, notify and react based on the current operating state, from per-packet dynamics to longstanding traffic trends and topological changes. However, the management and orchestration abilities of current SDN realisations is too limiting and must evolve for next generation networks. The current focus has been on logically centralising the routing and forwarding decisions. However, in order to achieve the necessary fine-grained insight, the data plane of the individual device must be programmable to collect and disseminate the metrics of interest.
The results of this work demonstrates that a logically centralised controller can dynamically collect and measure network operating metrics to subsequently compute and disseminate fine-tuned environment-specific settings. They show how this approach can prevent TCP throughput incast collapse and improve TCP performance by an order of magnitude for partition-aggregate traffic patterns. Futhermore, the paradigm is generalised to show the benefits for other services widely used in DCs such as, e.g, routing, telemetry, and security