Mapping virtual networks onto substrate networks

Network virtualization is a promising technique for building the Internet of the future since it enables the low cost introduction of new features into network elements. An open issue in such virtualization is how to effect an efficient mapping of virtual network elements onto those of the existing physical network, also called the substrate network. Mapping is an NP-hard problem and existing solutions ignore various real network characteristics in order to solve the problem in a reasonable time frame. This paper introduces new algorithms to solve this problem based on 0–1 integer linear programming, algorithms based on a whole new set of network parameters not taken into account by previous proposals. Approximative algorithms proposed here allow the mapping of virtual networks on large network substrates. Simulation experiments give evidence of the efficiency of the proposed algorithms.This research was partially financed by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), process 2010/03422-5

The Virtual Network Scheduling Problem for Heterogeneous Network Emulation Testbeds

Network testbeds such as Emulab and the Open Network Laboratory use virtualization to enable users to define end user virtual networks within a shared substrate. This involves mapping users\u27 virtual network nodes onto distinct substrate components and mapping virtual network links onto substrate paths. The mappings guarantee that different users\u27 activities can not interfere with one another. The problem of mapping virtual networks onto a shared substrate is a variant of the general graph embedding problem, long known to be NP-hard. In this paper, we focus on a more general version of the problem that supports advance scheduling of virtual network mappings. We experimentally study the performance of heuristic testbed schedulers in the context of the Open Network Laboratory. Our algorithms incorporate Mixed Integer Programs to optimally solve key subproblems, are fast enough to respond to reservation requests in under one second, and rarely reject requests needlessly

Virtual network mapping onto substrate networks

Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: A virtualização de redes é uma tecnologia promissora para ser utilizada como base na Internet do futuro, pois permite a introdução de novas funcionalidades nos elementos da rede a baixo custo. Uma das questões em virtualização de redes é como realizar o mapeamento eficiente de redes virtuais em substratos de redes, que é um problema de mapeamento é NP-Difícil. As soluções existentes na literatura ignoram várias características essenciais para ambientes reais a fim de que o problema possa ser resolvido em um intervalo de tempo razoável. Na presente dissertação, propõem-se oito algoritmos baseados em programação linear inteira 0-1 para resolver o problema de mapeamento que consideram diversas características realistas que não são incluídas em outras modelagens existentes. Seis dos algoritmos minimizam a largura de banda alocada e dois dos algoritmos minimizam o consumo de energia no substrato. Os algoritmos aproximativos propostos são capazes de determinar o mapeamento de redes virtuais em substratos de grande porte em poucos segundos e de encontrar soluções com qualidade, o que possibilita a adoção dos mesmos em mecanismos de controle de admissão em tempo realAbstract: Network virtualization is a promising technology to be employed in the future Internet, since it allows the introduction of new functionalities in network elements at low cost. One of the open questions in network virtualization is how to perform an efficient mapping of virtual networks in the substrate, which is NP-Hard problem. Existing solutions in the literature ignore several characteristics of real-world environments in order to solve the problem in a reasonable time frame. This paper introduces eight algorithms to solve the mapping problem that are based on 0-1 integer linear programming. One of the main contribution is the consideration of realistic assumptions to the problem that are not considered by others in the literature. Six algorithms minimize the allocated bandwidth and the two others minimize the power consumption in the substrate. The proposed approximative algorithms can map virtual networks in large substrates in few seconds and they find accurate solutions, which make them adequate to be employed in real-time admission controlMestradoCiência da ComputaçãoMestre em Ciência da Computaçã

Efficient Mapping of Virtual Networks onto a Shared Substrate

Virtualization has been proposed as a vehicle for overcoming the growing problem of internet ossification [1]. This paper studies the problem of mapping diverse virtual networks onto a common physical substrate. In particular, we develop a method for mapping a virtual network onto a substrate network in a cost-efficient way, while allocating sufficient capacity to virtual network links to ensure that the virtual network can handle any traffic pattern allowed by a general set of traffic constraints. Our approach attempts to find the best topology in a family of backbone-star topologies, in which a subset of nodes constitute the backbone, and the remaining nodes each connect to the nearest backbone node. We investigate the relative cost-effectiveness of different backbone topologies on different substrate networks, under a wide range of traffic conditions. Specifically, we study how the most cost-effective topology changes as the tightness of pairwise traffic constraints and the constraints on traffic locality are varied. In general, we find that as pairwise traffic constraints are relaxed, the least-cost backbone topology becomes increasingly tree-like . We also find that the cost of the constructed virtual networks is usually no more than 1.5 times a computed lower bound on the network cost and that the quality of solutions improves as the traffic locality gets weaker

Topological Embedding Feature Based Resource Allocation in Network Virtualization

Virtualization provides a powerful way to run multiple virtual networks on a shared substrate network, which needs accurate and efficient mathematical models. Virtual network embedding is a challenge in network virtualization. In this paper, considering the degree of convergence when mapping a virtual network onto substrate network, we propose a new embedding algorithm based on topology mapping convergence-degree. Convergence-degree means the adjacent degree of virtual network's nodes when they are mapped onto a substrate network. The contributions of our method are as below. Firstly, we map virtual nodes onto the substrate nodes with the maximum convergence-degree. The simulation results show that our proposed algorithm largely enhances the network utilization efficiency and decreases the complexity of the embedding problem. Secondly, we define the load balance rate to reflect the load balance of substrate links. The simulation results show our proposed algorithm achieves better load balance. Finally, based on the feature of star topology, we further improve our embedding algorithm and make it suitable for application in the star topology. The test result shows it gets better performance than previous works

Multicast Aware Virtual Network Embedding in Software Defined Networks

The Software Defined Networking (SDN) provides not only a higher level abstraction of lower level functionalities, but also flexibility to create new multicast framework. SDN decouples the low level network elements (forwarding/data plane) from the control/management layer (control plane), where a centralized controller can access and modify the configuration of each distributed network element. The centralized framework allows to develop more network functionalities that can not be easily achieved in the traditional network architecture. Similarly, Network Function Virtualization (NFV) enables the decoupling of network services from the underlying hardware infrastructure to allow the same Substrate (Physical) Network (SN) shared by multiple Virtual Network (VN) requests. With the network virtualization, the process of mapping virtual nodes and links onto a shared SN while satisfying the computing and bandwidth constraints is referred to as Virtual Network Embedding (VNE), an NP-Hard problem. The VNE problem has drawn a lot of attention from the research community. In this dissertation, we motivate the importance of characterizing the mode of communication in VN requests, and we focus our attention on the problem of embedding VNs with one-to-many (multicast) communication mode. Throughout the dissertation, we highlight the unique properties of multicast VNs and explore how to efficiently map a given Virtual Multicast Tree/Network (VMT) request onto a substrate IP Network or Elastic Optical Networks (EONs). The major objective of this dissertation is to study how to efficiently embed (i) a given virtual request in IP or optical networks in the form of a multicast tree while minimizing the resource usage and avoiding the redundant multicast tranmission, (ii) a given virtual request in optical networks while minimizing the resource usage and satisfying the fanout limitation on the multicast transmission. Another important contribution of this dissertation is how to efficiently map Service Function Chain (SFC) based virtual multicast request without prior constructed SFC while minimizing the resource usage and satisfying the SFC on the multicast transmission

Dynamic resource management in SDN-based virtualized networks

Network virtualization allows for an abstraction between user and physical resources by letting a given physical infrastructure to be shared by multiple service providers. However, network virtualization presents some challenges, such as, efficient resource management, fast provisioning and scalability. By separating a network's control logic from the underlying routers and switches, software defined networking (SDN) promises an unprecedented simplification in network programmability, management and innovation by service providers, and hence, its control model presents itself as a candidate solution to the challenges in network virtualization. In this paper, we use the SDN control plane to efficiently manage resources in virtualized networks by dynamically adjusting the virtual network (VN) to substrate network (SN) mappings based on network status. We extend an SDN controller to monitor the resource utilisation of VNs, as well as the average loading of SN links and switches, and use this information to proactively add or remove flow rules from the switches. Simulations show that, compared with three state-of-art approaches, our proposal improves the VN acceptance ratio by about 40% and reduces VN resource costs by over 10%