Providing guaranteed QoS in the hose-modeled VPN

With the development of the Internet, Internet service providers (ISPs) are required to offer revenue-generating and value-added services instead of only providing bandwidth and access services. Virtual Private Network (VPN) is one of the most important value-added services for ISPs. The classical VPN service is provided by implementing layer 2 technologies, either Frame Relay (FR) or Asynchronous Transfer Mode (ATM). With FR or ATM, virtual circuits are created before data delivery. Since the bandwidth and buffers are reserved, the QoS requirements can be naturally guaranteed. In the past few years, layer 3 VPN technologies are widely deployed due to the desirable performance in terms of flexibility, scalability and simplicity. Layer 3 VPNs are built upon IP tunnels, e.g., by using PPTP, L2TP or IPSec. Since IP is best-of-effort in nature, the QoS requirement cannot be guaranteed in layer 3 VPNs. Actually, layer 3 VPN service can only provide secure connectivity, i.e., protecting and authenticating IP packets between gateways or hosts in a VPN. Without doubt, with more applications on voice, audio and video being used in the Internet, the provision of QoS is one of the most important parts of the emerging services provided by ISPs. An intriguing question is: Is it possible to obtain the best of both layer 2 and 3 VPN? Is it possible to provide guaranteed or predictable QoS, as in layer 2 VPNs, while maintaining the flexibility and simplicity in layer 3 VPN? This question is the starting point of this study. The recently proposed hose model for VPN possesses desirable properties in terms of flexibility, scalability and multiplexing gain. However, the classic fair bandwidth allocation schemes and weighted fair queuing schemes raise the issue of low overall utilization in this model. A new fluid model for provider-provisioned virtual private network (PPVPN) is proposed in this dissertation. Based on the proposed model, an idealized fluid bandwidth allocation scheme is developed. This scheme is proven, analytically, to have the following properties: 1) maximize the overall throughput of the VPN without compromising fairness; 2) provide a mechanism that enables the VPN customers to allocate the bandwidth according to their requirements by assigning different weights to different hose flows, and thus obtain the predictable QoS performance; and 3) improve the overall throughput of the ISPs\u27 network. To approximate the idealized fluid scheme in the real world, the 2-dimensional deficit round robin (2-D DRR and 2-D DRR+) schemes are proposed. The integration of the proposed schemes with the best-effort traffic within the framework of virtual-router-based VPN is also investigated. The 2-D DRR and 2-D DER-+ schemes can be extended to multi-dimensional schemes to be employed in those applications which require a hierarchical scheduling architecture. To enhance the scalability, a more scalable non-per-flow-based scheme for output queued switches is developed as well, and the integration of this scheme within the framework of the MPLS VPN and applications for multicasting traffics is discussed. The performance and properties of these schemes are analyzed

Auto-bandwidth control in dynamically reconfigured hybrid-SDN MPLS networks

The proposition of this work is based on the steady evolution of bandwidth demanding technology, which currently and more so in future, requires operators to use expensive infrastructure capability smartly to maximise its use in a very competitive environment. In this thesis, a traffic engineering control loop is proposed that dynamically adjusts the bandwidth and route of flows of Multi-Protocol Label Switching (MPLS) tunnels in response to changes in traffic demand. Available bandwidth is shifted to where the demand is, and where the demand requirement has dropped, unused allocated bandwidth is returned to the network. An MPLS network enhanced with Software-defined Networking (SDN) features is implemented. The technology known as hybrid SDN combines the programmability features of SDN with the robust MPLS label switched path features along with traffic engineering enhancements introduced by routing protocols such as Border Gateway Patrol-Traffic Engineering (BGP-TE) and Open Shortest Path First-Traffic Engineering (OSPF-TE). The implemented mixed-integer linear programming formulation using the minimisation of maximum link utilisation and minimum link cost objective functions, combined with the programmability of the hybrid SDN network allows for source to destination demand fluctuations. A key driver to this research is the programmability of the MPLS network, enhanced by the contributions that the SDN controller technology introduced. The centralised view of the network provides the network state information needed to drive the mathematical modelling of the network. The path computation element further enables control of the label switched path's bandwidths, which is adjusted based on current demand and optimisation method used. The hose model is used to specify a range of traffic conditions. The most important benefit of the hose model is the flexibility that is allowed in how the traffic matrix can change if the aggregate traffic demand does not exceed the hose maximum bandwidth specification. To this end, reserved hose bandwidth can now be released to the core network to service demands from other sites

Topological Design of Multiple Virtual Private Networks UTILIZING SINK-TREE PATHS

With the deployment of MultiProtocol Label Switching (MPLS) over a core backbone networks, it is possible for a service provider to built Virtual Private Networks (VPNs) supporting various classes of services with QoS guarantees. Efficiently mapping the logical layout of multiple VPNs over a service provider network is a challenging traffic engineering problem. The use of sink-tree (multipoint-to-point) routing paths in a MPLS network makes the VPN design problem different from traditional design approaches where a full-mesh of point-to-point paths is often the choice. The clear benefits of using sink-tree paths are the reduction in the number of label switch paths and bandwidth savings due to larger granularities of bandwidth aggregation within the network. In this thesis, the design of multiple VPNs over a MPLS-like infrastructure network, using sink-tree routing, is formulated as a mixed integer programming problem to simultaneously find a set of VPN logical topologies and their dimensions to carry multi-service, multi-hour traffic from various customers. Such a problem formulation yields a NP-hard complexity. A heuristic path selection algorithm is proposed here to scale the VPN design problem by choosing a small-but-good candidate set of feasible sink-tree paths over which the optimal routes and capacity assignments are determined. The proposed heuristic has clearly shown to speed up the optimization process and the solution can be obtained within a reasonable time for a realistic-size network. Nevertheless, when a large number of VPNs are being layout simultaneously, a standard optimization approach has a limited scalability. Here, the heuristics termed the Minimum-Capacity Sink-Tree Assignment (MCSTA) algorithm proposed to approximate the optimal bandwidth and sink-tree route assignment for multiple VPNs within a polynomial computational time. Numerical results demonstrate the MCSTA algorithm yields a good solution within a small error and sometimes yields the exact solution. Lastly, the proposed VPN design models and solution algorithms are extended for multipoint traffic demand including multipoint-to-point and broadcasting connections

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

PhDAbstact not availableFujitsu Telecommunications Europe Lt

Integração do paradigma de cloud computing com a infraestrutura de rede do operador

Doutoramento em Engenharia InformáticaThe proliferation of Internet access allows that users have the possibility to use services available directly through the Internet, which translates in a change of the paradigm of using applications and in the way of communicating, popularizing in this way the so-called cloud computing paradigm. Cloud computing brings with it requirements at two different levels: at the cloud level, usually relying in centralized data centers, where information technology and network resources must be able to guarantee the demand of such services; and at the access level, i.e., depending on the service being consumed, different quality of service is required in the access network, which is a Network Operator (NO) domain. In summary, there is an obvious network dependency. However, the network has been playing a relatively minor role, mostly as a provider of (best-effort) connectivity within the cloud and in the access network. The work developed in this Thesis enables for the effective integration of cloud and NO domains, allowing the required network support for cloud. We propose a framework and a set of associated mechanisms for the integrated management and control of cloud computing and NO domains to provide endto- end services. Moreover, we elaborate a thorough study on the embedding of virtual resources in this integrated environment. The study focuses on maximizing the host of virtual resources on the physical infrastructure through optimal embedding strategies (considering the initial allocation of resources as well as adaptations through time), while at the same time minimizing the costs associated to energy consumption, in single and multiple domains. Furthermore, we explore how the NO can take advantage of the integrated environment to host traditional network functions. In this sense, we study how virtual network Service Functions (SFs) should be modelled and managed in a cloud environment and enhance the framework accordingly. A thorough evaluation of the proposed solutions was performed in the scope of this Thesis, assessing their benefits. We implemented proof of concepts to prove the added value, feasibility and easy deployment characteristics of the proposed framework. Furthermore, the embedding strategies evaluation has been performed through simulation and Integer Linear Programming (ILP) solving tools, and it showed that it is possible to reduce the physical infrastructure energy consumption without jeopardizing the virtual resources acceptance. This fact can be further increased by allowing virtual resource adaptation through time. However, one should have in mind the costs associated to adaptation processes. The costs can be minimized, but the virtual resource acceptance can be also reduced. This tradeoff has also been subject of the work in this Thesis.A proliferação do acesso à Internet permite aos utilizadores usar serviços disponibilizados diretamente através da Internet, o que se traduz numa mudança de paradigma na forma de usar aplicações e na forma de comunicar, popularizando desta forma o conceito denominado de cloud computing. Cloud computing traz consigo requisitos a dois níveis: ao nível da própria cloud, geralmente dependente de centros de dados centralizados, onde as tecnologias de informação e recursos de rede têm que ser capazes de garantir as exigências destes serviços; e ao nível do acesso, ou seja, dependendo do serviço que esteja a ser consumido, são necessários diferentes níveis de qualidade de serviço na rede de acesso, um domínio do operador de rede. Em síntese, existe uma clara dependência da cloud na rede. No entanto, o papel que a rede tem vindo a desempenhar neste âmbito é reduzido, sendo principalmente um fornecedor de conectividade (best-effort) tanto no dominio da cloud como no da rede de acesso. O trabalho desenvolvido nesta Tese permite uma integração efetiva dos domínios de cloud e operador de rede, dando assim à cloud o efetivo suporte da rede. Para tal, apresentamos uma plataforma e um conjunto de mecanismos associados para gestão e controlo integrado de domínios cloud computing e operador de rede por forma a fornecer serviços fim-a-fim. Além disso, elaboramos um estudo aprofundado sobre o mapeamento de recursos virtuais neste ambiente integrado. O estudo centra-se na maximização da incorporação de recursos virtuais na infraestrutura física por meio de estratégias de mapeamento ótimas (considerando a alocação inicial de recursos, bem como adaptações ao longo do tempo), enquanto que se minimizam os custos associados ao consumo de energia. Este estudo é feito para cenários de apenas um domínio e para cenários com múltiplos domínios. Além disso, exploramos como o operador de rede pode aproveitar o referido ambiente integrado para suportar funções de rede tradicionais. Neste sentido, estudamos como as funções de rede virtualizadas devem ser modeladas e geridas num ambiente cloud e estendemos a plataforma de acordo com este conceito. No âmbito desta Tese foi feita uma avaliação extensa das soluções propostas, avaliando os seus benefícios. Implementámos provas de conceito por forma a demonstrar as mais-valias, viabilidade e fácil implantação das soluções propostas. Além disso, a avaliação das estratégias de mapeamento foi realizada através de ferramentas de simulação e de programação linear inteira, mostrando que é possível reduzir o consumo de energia da infraestrutura física, sem comprometer a aceitação de recursos virtuais. Este aspeto pode ser melhorado através da adaptação de recursos virtuais ao longo do tempo. No entanto, deve-se ter em mente os custos associados aos processos de adaptação. Os custos podem ser minimizados, mas isso implica uma redução na aceitação de recursos virtuais. Esta compensação foi também um tema abordado nesta Tese

Hose Bandwidth Allocation Method to Achieve a Minimum Throughput Assurance Service for Provider Provisioned VPNs

We propose a hose bandwidth allocation method to achieve a minimum throughput assurance (MTA) service for the hose model. Although the hose model which has been proposed as a novel VPN service model for provider provisioned virtual private networks (PPVPNs) has been proven to be effective for network resource efficiency and configuration complexity there has been no consideration of a mechanism to assure quality of service (QoS) in the hose model. The basic idea of our method is to gather available bandwidth information from inside a network and use it to divide the available bandwidth into hoses on each bottleneck link. We evaluate and clarify our method through computer simulation runs. The simulation results show that our method can achieve an MTA service in the hose model. We propose a hose bandwidth allocation method to achieve a minimum throughput assurance (MTA) service for the hose model. Although the hose model, which has been proposed as a novel VPN service model for provider provisioned virtual private networks (PPVPNs), has been proven to be effective for network resource efficiency and configuration complexity, there has been no consideration of a mechanism to assure quality of service (QoS) in the hose model. The basic idea of our method is to gather available bandwidth information from inside a network and use it to divide the available bandwidth into hoses on each bottleneck link. We evaluate and clarify our method through computer simulation runs. The simulation results show that our method can achieve an MTA service in the hose model