Flexible Virtual Network Research Articles

NFVPermit: Toward Ensuring Performance Isolation in NFV-Based Systems

Network Functions Virtualization (NFV) promises programmability and cost savings by replacing hardware middleboxes with more flexible Virtual Network Functions (VNFs) on commodity servers. But, the current virtualization technologies do not fully isolate the system resources like Last Level Cache (LLC) and Memory Bandwidth (MB); therefore, co-location of VNFs on the same commodity server causes interference effects which might severely impact the performance of VNFs in terms of throughput, latency, etc. Contention at LLC is one of the root causes of this performance degradation and it is addressed by LLC resource partitioning. But, it remains unexplored the impact of both LLC and MB on VNF performance. In this work, we investigate the importance of MB partitioning along with LLC partitioning to achieve performance isolation in NFV-based systems. Allocating these system resources among co-located VNFs to meet Service Level Agreements (SLAs) is challenging due to the dynamic nature of traffic and varying functionality of VNFs. In this work, we formulate the resource allocation problem as an Integer Linear Programming (ILP) for maximizing the number of accepted VNF requests with SLA guarantees. Since the problem is NP-hard, we present a polynomial time -approximation scheme. Further, we propose a heuristic approach named NFVPermit, a resource manager for NFV-based systems that tries to ensure performance isolation among co-located VNFs based on their current traffic rates and SLA requirements. Through extensive experiments, we show how NFVPermit outperforms state-of-the-art and baseline approaches.

VTopology: Virtual MAC Address Aided Network Slicing in Multi-Tenant Data Centers

The shared nature of the network in Multi-Tenant Data Centers (MTDC) implies that network performance for tenants varies significantly. Efficient utilization of limited resources in MTDC is a challenge. Network virtualization is a promising technology for MTDC to provide customized and isolated networks to accommodate various tenants' demands. Driven by the massive increase of data traffic in MTDC, efficient and flexible network virtualization schemes are essential to guarantee seamless network resource sharing and complete isolation. This article presents a novel approach to customizing Virtual Topology (vTopology) for each tenant with self-control capability based on network slicing technology. The key technology behind this, a novel virtual MAC address (vMAC) is used to define network slices and act as a data link layer unique identifier in communications within vTopology virtual switches. Moreover, we propose Optimal Back-Forwarding Path (OBFP) to overcome interconnecting and data forwarding challenges between virtual switch ports allocated on different physical switches. With vTopology, we believe that the customization of virtual networks through network slicing technology enables MTDC operators to create more agile and flexible virtual networks and guarantee isolation and self-control for each tenant.

Virtual Network Control for Power Bills Reduction and Network Stability

The environmental load of telecommunication service provision is increasing due to the increase in communication traffic. Virtual networks have recently begun to spread, and flexible virtual network control is expected to reduce the operating costs of telecommunication services. This paper proposes a control method to achieve both reduced power bills and stable network operation when the electricity unit price differs among areas and time periods. To begin with, the problem to minimize power bills is formulated, and to solve it quickly, a heuristic search method is proposed that utilizes network centrality. In addition, we formulate a multi-objective optimization problem characterized by parameter normalization, and simulation results show that the proposed control method can reduce power bills while suppressing the number of network reconfigurations.

Elastic Provisioning of Stateful Telco Services in Mobile Cloud Networking

Several relevant research and innovation activities have recently investigated the technical and economic advantages of cloud computing for the provisioning of telco service infrastructures, in particular towards all-IP next generation 5G networks. In fact, the evolution of telco service infrastructures traditionally requires a significant upfront investment (and a long adoption process). Conversely, cloud exploitation significantly lowers investment risks by potentially providing elasticity in service provisioning via flexible Virtual Network Functions (VNFs) on top of a Network Functions Virtualization (NFV) Infrastructure. In this context, the paper presents novel solutions that we have designed, implemented, and evaluated within the EU FP7 Mobile Cloud Networking project (MCN). Their aim is to achieve cost-effective elastic provisioning of telco services over heterogeneous and federated cloud providers, with the specific focus of supporting the extreme quality levels that are demanded by traditional, non-virtualized, and dedicated telco infrastructures. In particular, we concentrate on how to effectively and efficiently automate service state migration for coarse-grained telco service (cloudified) components by leveraging industry-mature orchestration technologies and cloud management frameworks. While our proposed state migration model and procedure are general, its implementation is experimented for MCN's Rating, Charging, and Billing as a Service (RCBaaS). This MCN functionality has been chosen by purpose due to its challenging reliability and uptime requirements. The reported experimental and simulation results show the technical feasibility of the proposed solution under different and realistic load conditions for next-generation and cloudified 5G services.

A Multi-Domain VNE Algorithm Based on Load Balancing in the IoT Networks

The coordinated development of big data, Internet of Things, cloud computing and other technologies has led to an exponential growth in Internet business. However, the traditional Internet architecture gradually shows a rigid phenomenon due to the binding of the network structure and the hardware. In a high-traffic environment, it has been insufficient to meet people’s increasing service quality requirements. Network virtualization is considered to be an effective method to solve the rigidity of the Internet. Among them, virtual network embedding is one of the key problems of network virtualization. Since virtual network mapping is an NP-hard problem, a large number of research has focused on the evolutionary algorithm’s masterpiece genetic algorithm. However, the parameter setting in the traditional method is too dependent on experience, and its low flexibility makes it unable to adapt to increasingly complex network environments. In addition, link-mapping strategies that do not consider load balancing can easily cause link blocking in high-traffic environments. In the IoT environment involving medical, disaster relief, life support and other equipment, network performance and stability are particularly important. Therefore, how to provide a more flexible virtual network mapping service in a heterogeneous network environment with large traffic is an urgent problem. Aiming at this problem, a virtual network mapping strategy based on hybrid genetic algorithm is proposed. This strategy uses a dynamically calculated cross-probability and pheromone-based mutation gene selection strategy to improve the flexibility of the algorithm. In addition, a weight update mechanism based on load balancing is introduced to reduce the probability of mapping failure while balancing the load. Simulation results show that the proposed method performs well in a number of performance metrics including mapping average quotation, link load balancing, mapping cost-benefit ratio, acceptance rate and running time.

Dynamic Embedding and Quality of Service-Driven Adjustment for Cloud Networks

Cloud computing built on virtualization technologies can provide Internet service providers (SPs) with elastic virtualized node and link resources. SPs can outsource their virtualized resources as customized virtual networks (VNs) to end users. Hence, how to efficiently embed these VNs is the core issue in virtualization research. This technical issue is virtual network embedding (VNE). Since the issue inception, multiple mapping algorithms have been studied, including the reinforcement learning (RL) approach of machine learning. However, prior mapping algorithms are mostly static. Existing dynamic mapping algorithms just focus on accepting as many VNs as possible. No existing dynamic algorithm considers optimizing the quality of service (QoS) performance of each accepted VN. Optimizing the VN QoS performance is beneficial to guaranteeing service quality in cloud computing environment. On these backgrounds, we jointly investigate the dynamic VN embedding and optimize the QoS performance of each accepted VN. A dynamic heuristic algorithm is proposed in order to be evaluated in continuous time. When one VN service is requested, the VN will be mapped by the dynamic heuristic algorithm. If the QoS demand of the VN is not guaranteed, the reembedding scheme of the heuristic algorithm will be driven. Certain virtual elements of the VN will be adjusted. The dynamic embedding algorithm ensures flexible VN assignment and fulfills customized QoS demands. Finally, simulation results are illustrated in order to validate the strength of our dynamic algorithm. We perform the comparison with multiple existing dynamic algorithms. For instance, VN acceptance ratio of our dynamic heuristic algorithm improves at least 13 $\%$ .

Flexible Multimodal Sub-Gigahertz Communication for Heterogeneous Internet of Things Applications

To realize low-power and low-cost wireless communication over long distances, several wireless standards using sub-1 GHz frequencies have recently been proposed, each with their own strengths and weaknesses in terms of coverage, energy consumption, and throughput. However, none of them are currently flexible enough to satisfy the requirements of future dynamic and heterogeneous IoT applications. To alleviate this, a novel architecture that uses a multimodal device for flexibly employing a variety of heterogeneous sub-1 GHz wireless networks is proposed. It greatly increases network flexibility, resilience, and performance. A device design is presented together with an abstraction layer that combines the different networks into a single flexible virtual network substrate. The article elaborates on the qualitative advantages of this approach. Measurement-based simulation results show advantages in terms of energy efficiency, with significant reduction in energy use compared to a single-technology solution in a representative IoT track and trace scenario. Finally, the article identifies several open research challenges that need to be resolved to fully realize this vision of flexible multimodal communication for demanding IoT applications.

Virtual Network Survivability Through Joint Spare Capacity Allocation and Embedding

A key challenge in network virtualization is to efficiently map a virtual network (VN) on a substrate network (SN), while accounting for possible substrate failures. This is known as the survivable VN embedding (SVNE) problem. The state-of-the-art literature has studied the SVNE problem from infrastructure providers’ (InPs’) perspective, i.e., provisioning backup resources in the SN. A rather unexplored solution spectrum is to augment the VN with sufficient spare backup capacity to survive substrate failures and embed the resulting VN accordingly. Such augmentation enables InPs to offload failure recovery decisions to the VN operator, thus providing more flexible VN management. In this paper, we study the problem of jointly optimizing spare capacity allocation in a VN and embedding the VN to guarantee full bandwidth in the presence of multiple substrate link failures. We formulate the optimal solution to this problem as a quadratic integer program that we transform into an integer linear program. We also propose a heuristic algorithm to solve larger instances of the problem. Based on analytical study and simulation, our key findings are: 1) provisioning shared backup resources in the VN can yield ~33% more resource efficient embedding compared to doing the same at the SN level and 2) our heuristic allocates ~21% extra resources compared to the optimal, while executing several orders of magnitude faster.

Performance evaluation of revised virtual resources allocation scheme in network function virtualization (NFV) networks

The design, management, and operation of network infrastructure have evolved during the last few years, leveraging on innovative technologies and architectures. With such a huge trend, due to the flexibility and significant economic potential of these technologies, software-defined networking (SDN) and network functions virtualization (NFV) are emerging as the most indispensable key catalysers. SDN/NFV enhancing the infrastructure agility, thus network operators and service providers are able to program their own network functions (e.g., gateways, routers, load balancers) on vendor-independent hardware substrate. One of the most important considerations in NFV deployment is how to allocate the virtual resources that are needed to provide flexible virtual network services in an NFV-based network infrastructure. Thus, the most important prerequisite for NFV deployment is achieved fast, scalable and dynamic composition and allocation of networks functions (NFs) to implement network services (NSs). We have proposed a revised RA algorithm that integrates embedding and scheduling of virtual network functions (VNFs) simultaneously. In this paper, performance evaluation of the revised RA algorithm is performed and the proposed algorithm is applied more effectively in NFV environment where the demand for resources is flexible and concentrated.

Survivable Virtual Network Link Protection Method Based on Network Coding and Protection Circuit

Network virtualization is believed to be a promising way for the next generation Internet to overcome network ossification. It allows multiple heterogeneous virtual networks (VNs) to be embedded onto the shared substrate network (SN) to offer more flexibility and better manageability. With the increasing deployments of VNs in a variety of networks, how to protect the VNs against the single substrate link failure has become a key challenge. In this paper, we propose a survivable VN link protection method based on network coding and protection circuit. First, we provide an integer linear programming formulation for the survivable VN link protection to maximize the long-term average revenue to cost ratio. Second, a novel protection circuit technology is introduced to augment the VN at the VN level to reduce the backup resource consumption and provide more flexible VN management. Then, an efficient heuristic virtual network embedding algorithm is developed, which makes full use of the limited resources and transforms the single substrate link protection into the single virtual link protection in multiple protection circuits. Finally, the data units from different links are encoded using network coding, which not only provides 1 + N protection to virtual links but also reduces the recovery delay. The evaluation results show that our method not only has the best acceptance ratio and long-term average revenue to cost ratio, but it also greatly enhances the achievable backup sharing and shortens the average network recovery delay.

Virtual Network Embedding through Security Risk Awareness and Optimization

Network virtualization promises to play a dominant role in shaping the future Internet by overcoming the Internet ossification problem. However, due to the injecting of additional virtualization layers into the network architecture, several new security risks are introduced by the network virtualization. Although traditional protection mechanisms can help in virtualized environment, they are not guaranteed to be successful and may incur high security overheads. By performing the virtual network (VN) embedding in a security-aware way, the risks exposed to both the virtual and substrate networks can be minimized, and the additional techniques adopted to enhance the security of the networks can be reduced. Unfortunately, existing embedding algorithms largely ignore the widespread security risks, making their applicability in a realistic environment rather doubtful. In this paper, we attempt to address the security risks by integrating the security factors into the VN embedding. We first abstract the security requirements and the protection mechanisms as numerical concept of security demands and security levels, and the corresponding security constraints are introduced into the VN embedding. Based on the abstraction, we develop three security-risky modes to model various levels of risky conditions in the virtualized environment, aiming at enabling a more flexible VN embedding. Then, we present a mixed integer linear programming formulation for the VN embedding problem in different security-risky modes. Moreover, we design three heuristic embedding algorithms to solve this problem, which are all based on the same proposed node-ranking approach to quantify the embedding potential of each substrate node and adopt the k-shortest path algorithm to map virtual links. Simulation results demonstrate the effectiveness and efficiency of our algorithms.

FITS: A flexible virtual network testbed architecture

In this paper, we present the design and implementation of FITS (Future Internet Testbed with Security), an open, shared, and general-purpose testbed for the Future Internet. FITS defines an innovative architecture that allows users running experiments with new mechanisms and protocols using both Xen and OpenFlow on the same network infrastructure. FITS integrates several recognized state-of-the-art features such as plane separation, zero-loss network migration, and smartcard-driven security access, to cite a few. The current physical testbed is composed of nodes placed at several Brazilian and European institutions interconnected by encrypted tunnels. Besides presenting the FITS architecture and its features, we also discuss deployment challenges and how we have overcome them.

Shrinking network development time-scales: flexible virtual networks

A new type of virtual network is presented which allows the virtual network owner to exert control over their network resources in a completely flexible fashion. These virtual networks use a technique known as 'switchlets', which result from partitioning the resources, both physical and logical, of a switch. Each partition is a switchlet. Switchlets from different physical switches may be interconnected together in a manner consistent with the physical connectivity of the real switches. Each set of interconnected switchlets can be controlled by its own system, called a 'control architecture'. Such an arrangement results in a set of virtual networks, each with its own control architecture. These control architectures may be identical, that is they may be different instances of the same control architecture, or they may be radically different. This paper examines how switchlets can be used to provide functionality which is either impossible or problematic to provide using conventional approaches to network control.