Coordinated node and link mapping VNE using a new paths algebra strategy

AbstractThe main resource allocation research challenge in network virtualization is the Virtual Network Embedding (VNE) Problem. It consists of two stages, usually performed separately: node mapping and link mapping. A new mathematical multi-constraint routing framework for linear and non-linear metrics called “paths algebra” has already been proposed to solve the second stage, providing good results thanks to its flexibility. Unlike existing approaches, paths algebra is able to include any kind of network parameters (linear and non-linear) to solve VNE in reasonable runtime. While paths algebra had only been used to solve one stage (link mapping) of the VNE, this paper suggests an improvement to solve VNE using the paths algebra-based strategy by coordinating, in a single stage, the mapping of nodes and links based on a ranking made of the bi-directional pair of nodes of the substrate network, ordered by their available resources. Simulation results show that the New Paths Algebra-based strategy shows significant performance improvements when compared against the uncoordinated paths Algebra-based link mapping approach

Online power aware coordinated virtual network embedding with 5G delay constraint

Solving virtual network embedding problem with delay constraint is a key challenge to realize network virtualization for current and future 5G core networks. It is an NP-Hard problem, composed of two sub-problems, one for virtual node embedding, and another one for virtual edges embedding, usually solved separately or with a certain level of coordination, which in general could result on rejecting some virtualization requests. Therefore, the main contributions of this paper focused on introducing an online power aware algorithm to solve the virtual network embedding problem using less resources and less power consumption, while considering end-to-end delay as a main embedding constraint. The new algorithm minimizes the overall power of the physical network through efficiently maximizing the utilization of the active infrastructure resources and putting into sleeping mode all non-active ones. Evaluations of the proposed algorithm conducted against the state of art algorithms, and simulation results showed that, when end-to-end delay was not included the proposed online algorithm managed to reduce the total power consumption of the physical network by 23% lower than the online energy aware with dynamic demands VNE algorithm, EAD-VNE. However, when end-to-end delay was included, it significantly influenced the whole embedding process and resulted on reducing the average acceptance ratios by 16% compared to the cases without delay.Peer ReviewedPostprint (published version

Study, evaluation and contributions to new algorithms for the embedding problem in a network virtualization environment

Network virtualization is recognized as an enabling technology for the future Internet. It aims to overcome the resistance of the current Internet to architectural change and to enable a new business model decoupling the network services from the underlying infrastructure. The problem of embedding virtual networks in a substrate network is the main resource allocation challenge in network virtualization and is usually referred to as the Virtual Network Embedding (VNE) problem. VNE deals with the allocation of virtual resources both in nodes and links. Therefore, it can be divided into two sub-problems: Virtual Node Mapping where virtual nodes have to be allocated in physical nodes and Virtual Link Mapping where virtual links connecting these virtual nodes have to be mapped to paths connecting the corresponding nodes in the substrate network. Application of network virtualization relies on algorithms that can instantiate virtualized networks on a substrate infrastructure, optimizing the layout for service-relevant metrics. This class of algorithms is commonly known as VNE algorithms. This thesis proposes a set of contributions to solve the research challenges of the VNE that have not been tackled by the research community. To do that, it performs a deep and comprehensive survey of virtual network embedding. The first research challenge identified is the lack of proposals to solve the virtual link mapping stage of VNE using single path in the physical network. As this problem is NP-hard, existing proposals solve it using well known shortest path algorithms that limit the mapping considering just one constraint. This thesis proposes the use of a mathematical multi-constraint routing framework called paths algebra to solve the virtual link mapping stage. Besides, the thesis introduces a new demand caused by virtual link demands into physical nodes acting as intermediate (hidden) hops in a path of the physical network. Most of the current VNE approaches are centralized. They suffer of scalability issues and provide a single point of failure. In addition, they are not able to embed virtual network requests arriving at the same time in parallel. To solve this challenge, this thesis proposes a distributed, parallel and universal virtual network embedding framework. The proposed framework can be used to run any existing embedding algorithm in a distributed way. Thereby, computational load for embedding multiple virtual networks is spread across the substrate network Energy efficiency is one of the main challenges in future networking environments. Network virtualization can be used to tackle this problem by sharing hardware, instead of requiring dedicated hardware for each instance. Until now, VNE algorithms do not consider energy as a factor for the mapping. This thesis introduces the energy aware VNE where the main objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. To evaluate and validate the aforementioned VNE proposals, this thesis helped in the development of a software framework called ALgorithms for Embedding VIrtual Networks (ALEVIN). ALEVIN allows to easily implement, evaluate and compare different VNE algorithms according to a set of metrics, which evaluate the algorithms and compute their results on a given scenario for arbitrary parameters

Energy Efficient Core Networks with Clouds

The popularity of cloud based applications stemming from the high volume of connected mobile devices has led to a huge increase in Internet traffic. In order to enable easy access to cloud applications, infrastructure providers have invested in geographically distributed databases and servers. However, intelligent and energy efficient high capacity transport networks with near ubiquitous connectivity are needed to adequately and sustainably serve these requirements. In this thesis, network virtualisation has been identified as a potential networking paradigm that can contribute to network agility and energy efficiency improvements in core networks with clouds. The work first introduces a new virtual network embedding core network architecture with clouds and a compute and bandwidth resource provisioning mechanism aimed at reducing power consumption in core networks and data centres. Further, quality of service measures in compute and bandwidth resource provisioning such as delay and customer location have been investigated and their impact on energy efficiency established. Data centre location optimisation for energy efficiency in virtual network embedding infrastructure has been investigated by developing a MILP model that selects optimal data centre locations in the core network. The work also introduces an optical OFDM based physical layer in virtual network embedding to optimise power consumption and optical spectrum utilization. In addition, virtual network embedding schemes aimed at profit maximization for cloud infrastructure providers as well greenhouse gas emission reduction in cloud infrastructure networks have been investigated. GreenTouch, a consortium of industrial and academic experts on energy efficiency in ICTs, has adopted the work in this thesis as one of the measures of improving energy efficiency in core networks

Energy-Aware Traffic Engineering for Wired IP Networks

RÉSUMÉ Même si l'Internet est souvent considéré comme un moyen formidable pour réduire l'impact des activités humaines sur l'environnement, sa consommation d'énergie est en train de devenir un problème en raison de la croissance exponentielle du trafic et de l'expansion rapide des infrastructures de communication dans le monde entier. En 2007, il a été estimé que les équipements de réseau (sans tenir compte de serveurs dans les centres de données) étaient responsables d'une consommation d'énergie de 22 GW, alors qu'en 2010 la consommation annuelle des plus grands fournisseurs de services Internet (par exemple AT$T) a dépassé 10 TWh par an. En raison de cette tendance alarmante, la réduction de la consommation d'énergie dans les réseaux de télécommunication, et en particulier dans les réseaux IP, est récemment devenue une priorité. Une des stratégies les plus prometteuses pour rendre plus vert l'Internet est le sleep-based energy-aware network management (SEANM), selon lequel la configuration de réseau est adaptée aux niveaux de trafic afin d'endormir tous les éléments redondantes du réseau. Dans cette thèse nous développons plusieurs approches centralisées de SEANM, afin d'optimiser la configuration de réseaux IP qui utilisent différents protocoles (OSPF or MPLS) ou transportent différents types de trafic (élastique or inélastique). Le choix d'adresser le problème d'une manière centralisée, avec une plate-forme de gestion unique qui est responsable de la configuration et de la surveillance de l'ensemble du réseau, est motivée par la nécessité d'opérateurs de maintenir en tout temps le contrôle complet sur le réseau. Visant à mettre en œuvre les approches proposées dans un environnement réaliste du réseau, nous présentons aussi un nouveau cadre de gestion de réseau entièrement configurable que nous avons appelé JNetMan. JNetMan a été exploité pour tester une version dynamique de la procédure SEANM développée pour les réseaux utilisant OSPF.----------ABSTRACT Even if the Internet is commonly considered a formidable means to reduce the impact of human activities on the environment, its energy consumption is rapidly becoming an issue due to the exponential traffic growth and the rapid expansion of communication infrastructures worldwide. Estimated consumption of the network equipment, excluding servers in data centers, in 2007 was 22 GW, while in 2010 the yearly consumption of the largest Internet Service Providers, e.g., AT&T, exceeded 10 TWh per year. The growing energy trend has motivated the development of new strategies to reduce the consumption of telecommunication networks, with particular focus on IP networks. In addition to the development of a new generation of green network equipment, a second possible strategy to optimize the IP network consumption is represented by sleep-based energy-aware network management (SEANM), which aims at adapting the whole network power consumption to the traffic levels by optimizing the network configuration and putting to sleep the redundant network elements. Device sleeping represents the main potential source of saving because the consumption of current network devices is not proportional to the utilization level: so that, the overall network consumption is constantly close to maximum. In current IP networks, quality of service (QoS) and network resilience to failures are typically guaranteed by substantially over-dimensioning the whole network infrastructure: therefore, also during peak hours, it could be possible to put to sleep a non-negligible subset of redundant network devices. Due to the heterogeneity of current network technologies, in this thesis, we focus our efforts to develop centralized SEANM approaches for IP networks operated with different configurations and protocols. More precisely, we consider networks operated with different routing schemes, namely shortest path (OSPF), flow-based (MPLS) and take into account different types of traffic, i.e., elastic or inelastic. The centralized approach, with a single management platform responsible for configuring and monitoring the whole network, is motivated by the need of network operators to be constantly in control of the network dynamics. To fully guarantee network stability, we investigate the impact of SEANM on network reliability to failures and robustness to traffic variations. Ad hoc modeling techniques are integrated within the proposed SEANM frameworks to explicitly consider resilience and robustness as network constraints. Finally, to implement the proposed procedures in a realistic network environment, we propose a novel, fully configurable network management framework, called JNetMan. We use JNetMan to develop and test a dynamic version of the SEANM procedure for IP networks operated with shortest path routing protocols

Greener networking in a network virtualization environment

Energy consumption of network operators can be minimized by the dynamic and smart relocation of networking resources. In this paper, we propose to take advantage of network virtualization to enable a smart energy aware network provisioning. The virtualization of networking resources leads to the problem of mapping virtual demands to physical resources, known as Virtual Network Embedding (VNE). Our proposal modifies and improves exact existing energy aware VNE proposals where the objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. As exact energy efficient VNE approaches are hard to solve for large network sizes and have an adverse effect in the number of successful embeddings, an heuristic approach to reconfigure the allocation of already embedded virtual networks, minimizing the energy consumption, is also proposed.Peer Reviewe

Greener networking in a network virtualization environment

Energy consumption of network operators can be minimized by the dynamic and smart relocation of networking resources. In this paper, we propose to take advantage of network virtualization to enable a smart energy aware network provisioning. The virtualization of networking resources leads to the problem of mapping virtual demands to physical resources, known as Virtual Network Embedding (VNE). Our proposal modifies and improves exact existing energy aware VNE proposals where the objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. As exact energy efficient VNE approaches are hard to solve for large network sizes and have an adverse effect in the number of successful embeddings, an heuristic approach to reconfigure the allocation of already embedded virtual networks, minimizing the energy consumption, is also proposed.Peer Reviewe