499 research outputs found
Algorithms for advance bandwidth reservation in media production networks
Media production generally requires many geographically distributed actors (e.g., production houses, broadcasters, advertisers) to exchange huge amounts of raw video and audio data. Traditional distribution techniques, such as dedicated point-to-point optical links, are highly inefficient in terms of installation time and cost. To improve efficiency, shared media production networks that connect all involved actors over a large geographical area, are currently being deployed. The traffic in such networks is often predictable, as the timing and bandwidth requirements of data transfers are generally known hours or even days in advance. As such, the use of advance bandwidth reservation (AR) can greatly increase resource utilization and cost efficiency. In this paper, we propose an Integer Linear Programming formulation of the bandwidth scheduling problem, which takes into account the specific characteristics of media production networks, is presented. Two novel optimization algorithms based on this model are thoroughly evaluated and compared by means of in-depth simulation results
Orchestration of Network Services Across Multiple Operators: The 5G Exchange Prototype
Future 5G networks will rely on the coordinated
allocation of compute, storage, and networking resources in
order to meet the functional requirements of 5G services as well
as guaranteeing efficient usage of the network infrastructure.
However, the 5G service provisioning paradigm will also require
a unified infrastructure service market that integrates multiple
operators and technologies. The 5G Exchange (5GEx) project,
building heavily on the Software-Defined Network (SDN) and the
Network Function Virtualization (NFV) functionalities, tries to
overcome this market and technology fragmentation by
designing, implementing, and testing a multi-domain
orchestrator (MdO) prototype for fast and automated Network
Service (NS) provisioning over multiple-technologies and
spanning across multiple operators. This paper presents a first
implementation of the 5GEx MdO prototype obtained by
extending existing open source software tools at the disposal of
the 5GEx partners. The main functions of the 5GEx MdO
prototype are showcased by demonstrating how it is possible to
create and deploy NSs in the context of a Slice as a Service
(SlaaS) use-case, based on a multi-operator scenario. The 5GEx
MdO prototype performance is experimentally evaluated
running validation tests within the 5GEx sandbox. The overall
time required for the NS deployment has been evaluated
considering NSs deployed across two operators
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
Semantic validation of affinity constrained service function chain requests
Network Function Virtualization (NFV) has been proposed as a paradigm to increase the cost-efficiency, flexibility and innovation in network service provisioning. By leveraging IT virtualization techniques in combination with programmable networks, NFV is able to decouple network functionality from the physical devices on which they
are deployed. This opens up new business opportunities for both Infrastructure Providers (InPs) as well as Service Providers (SPs), where the SP can request to deploy a chain of Virtual Network Functions (VNFs) on top of which its service can run. However, current NFV approaches lack the possibility for SPs to define location requirements and constraints on the mapping of virtual functions and paths onto physical hosts and links. Nevertheless, many scenarios
can be envisioned in which the SP would like to attach placement constraints for efficiency, resilience, legislative, privacy and economic reasons. Therefore, we propose a set of affinity and anti-affinity constraints, which can be used by SPs to define such placement restrictions. This newfound ability to add constraints to Service Function Chain (SFC) requests also introduces an additional risk that SFCs with conflicting constraints are requested or automatically
generated. Therefore, a framework is proposed that allows the InP to check the validity of a set of constraints and provide feedback to the SP. To achieve this, the SFC request and relevant information on the physical topology are modeled as an ontology of which the consistency can be checked using a semantic reasoner. Enabling semantic
validation of SFC requests, eliminates inconsistent SFCs requests from being transferred to the embedding algorithm.Peer Reviewe
An experimental study on latency-aware and self-adaptive service chaining orchestration in distributed NFV and SDN infrastructures
Network Function Virtualization (NFV) and Software Defined Networking (SDN) changed radically the way 5G networks will be deployed and services will be delivered to vertical applications (i.e., through dynamic chaining of virtualized functions deployed in distributed clouds to best address latency requirements). In this work, we present a service chaining orchestration system, namely LASH-5G, running on top of an experimental set-up that reproduces a typical 5G network deployment with virtualized functions in geographically distributed edge clouds. LASH-5G is built upon a joint integration effort among different orchestration solutions and cloud deployments and aims at providing latency-aware, adaptive and reliable service chaining orchestration across clouds and network resource domains interconnected through SDN. In this paper, we provide details on how this orchestration system has been deployed and it is operated on top of the experimentation infrastructure provided within the Fed4FIRE+ facility and we present performance results assessing the effectiveness of the proposed orchestration approach
Efficiency gains due to network function sharing in CDN-as-a-Service slicing scenarios
Proceedings of: IEEE 7th International Conference on Network Softwarization (NetSoft), 28 June-2 July 2021, Tokyo, Japan.The consumption of video contents is currently dominating the traffic observed in ISP networks. The distribution of that content is usually performed leveraging on CDN caches storing and delivering multimedia. The advent of virtualization is bringing attention to the CDN as use case for virtualizing the cache function. In parallel, there is a trend on sharing network infrastructures as a way of reducing deployment costs by ISPs. Then, an interesting scenario emerges when considering the possibility of sharing virtualized cache functions among ISPs sharing a common physical infrastructure, mostly considering that usually those ISPs offer similar content catalogues to final end users. This paper investigates through simulations the potential efficiencies that can be achieved when sharing a virtual cache function if compared to the classical approach of independent virtual caches operated per ISP.This work has been partly funded by the project 5GROWTH (Grant Agreement no. 856709)
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