Xavier Hesselbach

Energy Efficient Virtual Network Embedding

Waste of energy due to over-provisioning and over-dimensioning of network infrastructures has recently stimulated the interest on energy consumption reduction by Internet Service Providers (ISPs). By means of resource consolidation, network virtualization based architectures will enable energy saving. In this letter, we extend the well-known virtual network embedding problem (VNE) to energy awareness and propose a mixed integer program (MIP) which provides optimal energy efficient embeddings. Simulation results show the energy gains of the proposed MIP over the existing cost-based VNE approach.

Optimal mapping of virtual networks with hidden hops

Network virtualization has emerged as a solution for the Internet inability to address the required challenges caused by the lack of coordination among Internet service providers for the deployment of new services. The allocation of resources is one of the main problems in network virtualization, mainly in the mapping of virtual nodes and links to specific substrate nodes and paths, also known as the virtual network embedding problem. This paper proposes an algorithm based on optimization theory, to map the virtual links and nodes requiring a specific demand, looking for the maximization of the spare bandwidth and spare CPU in the substrate network, taking into account the CPU demanded by the hidden hops when a virtual link is mapped. The components of the virtual networks (nodes and links) that do not ask for an specific demand are then allocated following a fairness criteria.

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.

ALEVIN - A Framework to Develop, Compare, and Analyze Virtual Network Embedding Algorithms

Network virtualization is recognized as an enabling technology for the Future Internet. Applying virtualization of network resources leads to the problem of mapping virtual resources to physical resources, known as “Virtual Network Embedding” (VNE). Several algorithms attempting to solve this problem have been discussed in the literature, so far. However, comparison of VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, we introduce a framework to compare different algorithms according to a set of metrics, which allow to evaluate the algorithms and compute their results on a given scenario for arbitrary parameters.

A distributed, parallel, and generic virtual network embedding framework

One of the main challenges of network virtualization is the mapping of virtual network demands to physical network resources, commonly known as the virtual network embedding (VNE) problem. This paper introduces DPVNE, a distributed, parallel and generic VNE framework. DPVNE can be used 1) to run various cost-reducing embedding algorithms 2) in a distributed way. Thereby, computational load for embedding multiple virtual networks is spread across the substrate network reducing workload of individual nodes and 3) enabling the embedding of multiple virtual networks in parallel. DPVNE, in contrast to existing distributed algorithms, 4) achieves lower message overhead and, despite of being distributed, 5) keeps embedding costs comparable to those of centralized approaches.

On the complex scheduling formulation of virtual network functions over optical networks

Software-Defined Networking and Network Functions Virtualisation has brought a revolution within the telecom market landscape. Initial proof-of-concept prototypes for NFV-enabled solutions are being developed at the same time SDN models are identified as the futures solutions within the telecom realm. We provide in this article an overview of the SDN/NFV technologies over optical networks, as well as we provide the first formalisation model for the virtual network function complex scheduling problem. The article aims at being used as starting point in order to optimally solve the scheduling problem of virtual network functions that compose network services to be provisioned within the SDN paradigm.

Planning of dynamic virtual optical cloud infrastructures: The GEYSERS approach

This article focuses on planning and replanning of virtual infrastructures over optical cloud infrastructures comprising integrated optical network and IT resources. This concept has been developed in the context of the European project GEYSERS. GEYSERS has proposed a novel multi-layer architecture, described in detail, that employs optical networking capable of provisioning optical network and IT resources for end-to-end cloud service delivery. The procedures required to perform virtual infrastructure planning and replanning at the different architecture layers are also detailed. An optimization scheme suitable to dynamically plan and replan virtual infrastructures is presented and compared to conventional approaches, and the benefits of dynamic replanning are discussed and quantified. The final project demonstration, focusing on planning, replanning, and dynamically establishing virtual infrastructures over the physical resources, is presented, while some emulation results are provided to further evaluate the performance of the GEYSERS solution.

The bottlenecked virtual network problem in bandwidth allocation for network virtualization

Internet is becoming unable to overcome the challenges required by new services due to the lack of coordination among Internet service providers. This situation, frequently called network ossification, makes increasingly hard the deployment and the testing new network technologies.

IntServ6: an approach to support QoS over IPv6 networks

This paper proposes an approach to support end-to-end quality of service over IPv6 networks. In our solution, IPv6 flow labels are used to give better performance into the process of packet classification on network routers. In order to evaluate our proposal, a router model is obtained and it is compared with other technologies as IntServ and MPLS. As result, we obtain a solution with benefits of QoS support and label switching in IPv6 routers.

Hashing based traffic partitioning in a multicast-multipath MPLS network model

Load Balancing is a key mechanism in traffic engineering. One interesting strategy for load balancing enhancement is the multipath approach, in which data is transmitted through different paths. The use of effective hashing functions for load balancing optimizes the network utilization and reduces packet disordering and imbalance. This paper address the problem of packet ordering in multipath - multicast MPLS networks, studies the impact of the hashing function to effectively partition the traffic to implement the flow splitting values issued from an optimized model and analyzes the traffic allocation to the LSPs of the network and the mis-ordering problem at the egress node using buffer schemes. The buffer allocation levels are calculated according to end-to-end delays. Finally, the paper presents some experimental results from an optimized network.