A Survey of Controller Placement Problem in Software Defined Networks

Software Defined Network (SDN) is an emerging network paradigm which provides a centralized view of the network by decoupling the network control plane from the data plane. This strategy of maintaining a global view of the network optimizes resource management. However, the implementation of SDN using a single physical controller lead to issues of scalability and robustness. A physically distributed but logically centralized SDN controller architecture promises to resolve both these issues. Distributed SDN along with its benefits brings along the problem of the number of controllers required and their placement in the network. This problem is referred to as the controller placement problem (CPP) and this paper is mainly concerned with the CPP solution techniques. The paper formally defines CPP, gives a comprehensive review of the various performance metrics and characteristics of the available CPP solutions. Finally, we point out the existing literature gap and discuss the future research direction in this domain

Management and Orchestration of Network Slices in 5G, Fog, Edge and Clouds

Network slicing allows network operators to build multiple isolated virtual networks on a shared physical network to accommodate a wide variety of services and applications. With network slicing, service providers can provide a cost-efficient solution towards meeting diverse performance requirements of deployed applications and services. Despite slicing benefits, End-to-End orchestration and management of network slices is a challenging and complicated task. In this chapter, we intend to survey all the relevant aspects of network slicing, with the focus on networking technologies such as Software-defined networking (SDN) and Network Function Virtualization (NFV) in 5G, Fog/Edge and Cloud Computing platforms. To build the required background, this chapter begins with a brief overview of 5G, Fog/Edge and Cloud computing, and their interplay. Then we cover the 5G vision for network slicing and extend it to the Fog and Cloud computing through surveying the state-of-the-art slicing approaches in these platforms. We conclude the chapter by discussing future directions, analyzing gaps and trends towards the network slicing realization.Comment: 31 pages, 4 figures, Fog and Edge Computing: Principles and Paradigms, Wiley Press, New York, USA, 201

SDN Partitioning: A Centralized Control Plane for Distributed Routing Protocols

Hybrid IP networks that use both control paradigms - distributed and centralized - promise the best of two worlds: programmability and agility of SDN, and reliability and fault tolerance of distributed routing protocols like OSPF. The common approaches follow a division of labor concept, where SDN controls prioritized traffic and OSPF assures care-free operation of best effort traffic. We propose SDN Partitioning, which establishes centralized control over the distributed routing protocol by partitioning the topology into sub-domains with SDN-enabled border nodes, such that OSPF's routing updates have to traverse SDN border nodes to reach neighboring sub-domains. This allows the central controller to modify how sub-domains view one another, which in turn allows to steer inter-sub-domain traffic. The degree of dynamic control against simplicity of OSPF can be trade off by adjusting the size of the sub-domains. This paper explains the technical requirements, presents a novel scheme for balanced topology partitioning, and provides the models for common network management tasks. Our performance evaluation shows that - already in its minimum configuration with two sub-domains - SDN Partitioning provides significant improvements in all respects compared to legacy routing protocols, whereas smaller sub-domains provide network control capabilities comparable to full SDN deployment.Comment: 14 pages, 12 figure

Virtual Machine Migration Planning in Software-Defined Networks

In this paper, we examine the problem of how to schedule the migrations and how to allocate network resources for migration when multiple VMs need to be migrated at the same time. We consider the problem in the Software-defined Network (SDN) context since it provides flexible control on routing. More specifically, we propose a method that computes the optimal migration sequence and network bandwidth used for each migration. We formulate this problem as a mixed integer programming, which is NP-hard. To make it computationally feasible for large scale data centers, we propose an approximation scheme via linear approximation plus fully polynomial time approximation, and obtain its theoretical performance bound. Through extensive simulations, we demonstrate that our fully polynomial time approximation (FPTA) algorithm has a good performance compared with the optimal solution and two state of-the-art algorithms. That is, our proposed FPTA algorithm approaches to the optimal solution with less than 10% variation and much less computation time. Meanwhile, it reduces the total migration time and the service downtime by up to 40% and 20% compared with the state-of-the-art algorithms, respectively.Comment: To appear at Infocom 201

Can SDN Mitigate Disasters?

Datacenter networks and services are at risk in the face of disasters. Existing fault-tolerant storage services cannot even achieve a nil recovery point objective (RPO) as client-generated data may get lost before the termination of their migration across geo-replicated datacenters. SDN has proved instrumental in exploiting application-level information to optimise the routing of information. In this paper, we propose Software Defined Edge (SDE) or the implementation of SDN at the network edge to achieve nil RPO. We illustrate our proposal with a fault-tolerant key-value store that experimentally recovers from disaster within 30s. Although SDE is inherently fault-tolerant and scalable, its deployment raises new challenges on the partnership between ISPs and CDN providers. We conclude that failure detection information at the SDN-level can effectively benefit applications to recover from disaster

Survey on Network Virtualization Hypervisors for Software Defined Networking

Software defined networking (SDN) has emerged as a promising paradigm for making the control of communication networks flexible. SDN separates the data packet forwarding plane, i.e., the data plane, from the control plane and employs a central controller. Network virtualization allows the flexible sharing of physical networking resources by multiple users (tenants). Each tenant runs its own applications over its virtual network, i.e., its slice of the actual physical network. The virtualization of SDN networks promises to allow networks to leverage the combined benefits of SDN networking and network virtualization and has therefore attracted significant research attention in recent years. A critical component for virtualizing SDN networks is an SDN hypervisor that abstracts the underlying physical SDN network into multiple logically isolated virtual SDN networks (vSDNs), each with its own controller. We comprehensively survey hypervisors for SDN networks in this article. We categorize the SDN hypervisors according to their architecture into centralized and distributed hypervisors. We furthermore sub-classify the hypervisors according to their execution platform into hypervisors running exclusively on general-purpose compute platforms, or on a combination of general-purpose compute platforms with general- or special-purpose network elements. We exhaustively compare the network attribute abstraction and isolation features of the existing SDN hypervisors. As part of the future research agenda, we outline the development of a performance evaluation framework for SDN hypervisors.Comment: IEEE Communications Surveys and Tutorials, in print, 201

HyMER: A Hybrid Machine Learning Framework for Energy Efficient Routing in SDN

Software-defined networks (SDN) with programmable data plane and machine learning for discovering patterns are utilized in security, traffic classification, quality of services prediction, and network performance, that has increasing research attention. Addressing the significance of energy efficiency in networks, we propose a novel hybrid machine learning-based framework named HyMER that combines the capabilities of SDN and machine learning for traffic-aware energy efficient routing. To the best of our knowledge, HyMER is the first that utilizes a hybrid machine learning solution with supervised and reinforcement learning components for energy efficiency and network performance in SDN. The supervised learning component consists of feature extraction, training, and testing. The reinforcement learning component learns from existing data or from scratch by iteratively interacting with the network environment. The HyMER framework is developed on POX controller and is evaluated on Mininet using real-world topologies and dynamic traffic traces. Experimental results show that the supervised component achieves up to 70% feature size reduction and more than 80\% accuracy in parameter prediction. We demonstrate that combining the supervised and reinforcement methods not only does capture the dynamic change more efficiently but also increases the convergence speed. As compared to state-of-the-art utility based energy saving approaches, HyMER heuristics has shown up to 50% link saving, and also exhibits up to 14.7 watts less power consumption for realistic network topology and traffic traces.Comment: Double column 12 pages, 13 figures, 6 table

DDoS Attacks: Tools, Mitigation Approaches, and Probable Impact on Private Cloud Environment

The future of the Internet is predicted to be on the cloud, resulting in more complex and more intensive computing, but possibly also a more insecure digital world. The presence of a large amount of resources organized densely is a key factor in attracting DDoS attacks. Such attacks are arguably more dangerous in private individual clouds with limited resources. This paper discusses several prominent approaches introduced to counter DDoS attacks in private clouds. We also discuss issues and challenges to mitigate DDoS attacks in private clouds

A Comprehensive Study on Load Balancers for VNF chains Horizontal Scaling

We present an architectural design and a reference implementation for horizontal scaling of virtual network function chains. Our solution does not require any changes to network functions and is able to handle stateful network functions for which states may depend on both directions of the traffic. We use connection-aware traffic load balancers based on hashing function to maintain mappings between connections and the dynamically changing network function chains. Our references implementation uses OpenFlow switches to route traffic to the assigned network function instances according to the load balancer decisions. We conducted extensive simulations to test the feasibility of the architecture and evaluate the performance of our implementation.Comment: Short version of the paper has been accepted for CNSM 201

A Survey on Software-Defined VANETs: Benefits, Challenges, and Future Directions

The evolving of Fifth Generation (5G) networks isbecoming more readily available as a major driver of the growthof new applications and business models. Vehicular Ad hocNetworks (VANETs) and Software Defined Networking (SDN)represent the key enablers of 5G technology with the developmentof next generation intelligent vehicular networks and applica-tions. In recent years, researchers have focused on the integrationof SDN and VANET, and look at different topics related to thearchitecture, the benefits of software-defined VANET servicesand the new functionalities to adapt them. However, securityand robustness of the complete architecture is still questionableand have been largely negleted. Moreover, the deployment andintegration of novel entities and several architectural componentsdrive new security threats and vulnerabilities.In this paper, first we survey the state-of-the-art SDN basedVehicular ad-hoc Network (SDVN) architectures for their net-working infrastructure design, functionalities, benefits, and chal-lenges. Then we discuss these SDVN architectures against majorsecurity threats that violate the key security services such asavailability, confidentiality, authentication, and data integrity.We also propose different countermeasures to these threats.Finally, we discuss the lessons learned with the directions offuture research work towards provisioning stringent security andprivacy solutions in future SDVN architectures. To the best of ourknowledge, this is the first comprehensive work that presents sucha survey and analysis on SDVNs in the era of future generationnetworks (e.g., 5G, and Information centric networking) andapplications (e.g., intelligent transportation system, and IoT-enabled advertising in VANETs).Comment: 17 pages, 2 figure