CDRA: A Community Detection based Routing Algorithm for Link Failure Recovery in Software Defined Networks

Accurate traffic and latency measurements are the foundation of many network management tasks, including traffic engineering and network provision, network diagnosis and fault recovery. However, SNMP-based traffic measurement techniques in traditional IP networks only provide measurements for link loads, which cannot lead to accurate measurements. For link latency measurement, it has been shown that a traditional IP network needs to deploy a large number of monitors to achieve accurate measurements. The software-defined network (SDN) architecture opens up new opportunities to tackle the traffic matrix estimation and latency measurement problems. For the traffic estimation problem, the counter in a flow table entry of an SDN switch can directly measure the size of a matched flow. This dramatically increases the number and type of flows that can be measured accurately. For link latency measurement, SDN switches provide flexible routing and hence allow even non-shortest paths to be measured in the network. This routing flexibility can reduce the number of monitors deployed in the network to achieve a complete measurement of all the link latencies. But the additional measurement capabilities of SDNs also have limitations: the flow table entries added for measurements must be limited due to the high cost of ternary content-addressable memory (TCAM), and the amount of additional traffic for measurement should also be confined. Under these constraints, this research investigates the traffic matrix estimation and link latency measurement problems for a pure SDN network and a hybrid SDN network. A hybrid network, which consists of SDN switches and conventional routers, will exist for some time to come since it is economically impossible to replace every conventional router overnight. For the traffic matrix estimation problem, we propose a new estimation framework, which can be used in both SDNs and hybrid SDNs. Performance evaluation results show that the new framework can achieve highly accurate traffic measurement with a small number of TCAM entries. For the link latency measurement problem, we first present minimum monitor placement schemes in hybrid SDNs. It has been shown that our schemes not only reduce the number of required monitors but also guarantee full link measurements even when link weights change. We then present two time-stamp-based link latency measurement schemes for pure SDNs and show that the proposed schemes can minimize the number of consumed TCAM entries and the amount of traffic generated for measurement.

The Internet has caused the advent of a digital society; wherein almost everything is connected and available from any place. Thus, regardless of their extensive adoption, traditional IP networks are yet complicated and arduous to operate. Therefore, there is difficulty in configuring the network in line with the predefined procedures and responding to the load modifications and faults through network reconfiguring. The current networks are likewise vertically incorporated to make matters far more complicated: the control and data planes are bundled collectively. Software-Defined Networking (SDN) is an emerging concept which aims to change this situation by breaking vertical incorporation, promoting the logical centralization of the network control, separating the network control logic from the basic switches and routers, and enabling the network programming. The segregation of concerns identified between the policies concept of network, their implementation in hardware switching and data forwarding is essential to the flexibility required: SDN makes it less complicated and facilitates to make and introduce new concepts in networking through breaking the issue of the network control into tractable parts, simplifies the network management and facilitate the development of the network. In this paper, the SDN is reviewed; it introduces SDN, explaining its core concepts, how it varies from traditional networking, and its architecture principles. Furthermore, we presented the crucial advantages and challenges of SDN, focusing on scalability, security, flexibility, and performance. Finally, a brief conclusion of SDN is revised.

Legacy IP-upgraded SDN nodes tradeoff in energy-efficient hybrid IP/SDN networks

Computer networks are the fundamental infrastructure of intelligent environments (IEs). Software defined network (SDN) is an emerging software-based network architecture that separates the control plane from data plane to facilitate dynamic network management and configuration; two important parameters which are essential in real-time IEs. This separation alleviates network administrators to implement efficient fault tolerance strategies and increasing reliability and quality of service (QoS). Hence, they can make their networks more reliable and as a result, decrease the adverse effects due to network failures. As a result, SDN is a candidate for using in new IEs such as internet of things (IoT). The control plane of SDN can be deployed on the IoT cloud server to manage the entire network. Link failure is one of the most common and critical failures in such computer networks which causes dropping of data packets and reduces network performance considerably. A survivable traffic engineering (TE) method can provide protection against link failures and heighten the reliability of data transmission. To this purpose, this paper proposes an efficient and survivable software-based TE model over SDN called EFSUTE to increase reliability in real-time IEs. EFSUTE leverages the capabilities of SDN to compute and install two disjoint paths between any source–destination pair in the network. EFSUTE models network routing as a Shared Risk Link Group problem which provides topological diversity. This policy increases the survivability by providing alternative paths between network hosts. To prove the effectiveness of EFSUTE, we conducted extensive simulations and compared it with restoration techniques. Experimental results confirm that EFSUTE can be practically used in SDN and efficiently protects the network traffics against link failures to increase safety and provides a reliable software based infrastructure with QoS for real-time IEs.

Energy aware routing aims at reducing the energy consumption of ISP networks. The idea is to adapt routing to the traffic load in order to turn off some hardware. However, it implies to make dynamic changes to routing configurations which is almost impossible with legacy protocols. The Software Defined Network (SDN) paradigm bears the promise of allowing a dynamic optimization with its centralized controller. In this work, we propose SENAtoR, an algorithm to enable energy aware routing in a scenario of progressive migration from legacy to SDN hardware. Since in real life, turning off network equipments is a delicate task as it can lead to packet losses, SENAtoR provides also several features to safely enable energy saving services: tunneling for fast rerouting, smooth node disabling and detection of both traffic spikes and link failures. We validate our solution by extensive simulations and by experimentation. We show that SENAtoR can be progressively deployed in a network using the SDN paradigm. It allows to reduce the energy consumption of ISP networks by 5 to 35% depending on the penetration of SDN hardware, while diminishing the packet loss rate compared to legacy protocols.

Scalable multicasting with multiple shared trees in software defined networking

In recent years, SDN has evolved as a promising alternative to the traditional networking paradigm. This is because the traditional network is decentralized, making it difficult to manage and provide trouble-shooting. SDN is an approach to network management whereby the forwarding process of the data plane (DP) is disassociated from the control plane (CP). The CP is responsible for decision-making. SDN centrally control the network infrastructure and make it programmable. Communication between the two planes (data and control) is carried out by the OpenFlow (OF) protocol. The deployment of SDN was initiated by Mr. Matrin Casado and his research team in 2008. The original projects developed at Stanford University were SANE and ETHANE. Security reports and web articles suggest that SDN (Software Defined Network) has the caliber to defend DDoS attacks. The year 2017 has been declared as the year of SDN adaption and DDoS mitigation. The initial effort in the direction of compiling the detection and mitigation approaches has been done in (Dayal et al., 2016). Recently a similar effort has been done in (Rochak et al., 2019). The CP of SDN has a complete visibility of the network which makes traffic monitoring feasible. Moreover, SDN open flow switches contain forwarding logic only; decision-making capability is softwarized at 58controller. This helps the controller to instruct and configure the switches with new flow rules which the switches follow. This facilitates the network admins to detect and mitigate these attacks easily. SDN have gained momentum among the possible solutions of DDoS attacks due to its decentralized nature of network management, but solutions come with its repercussions. The centralization and open architecture framework makes SDN difficult for widespread adaptation. The chapter begins with an introduction to DDoS attacks and its classification such as volumetric attack, protocol exploitation attack and application attack. In the next section, we discuss the possible DDoS attacks over SDN framework. We have categorized the vulnerability into three classes: DDoS attack on data, control, and application planes (APs). The DDoS attack on DP can further be classified into TCAM exhaustion, switch DDoS, ICMP flood, TCP flood, TCP_SYN flood, etc. We would discuss Resource depletion, OF bandwidth exhaustion, amplification attacks in DDoS attack over CP. HTTP flooding and Slowloris attack has been discussed in DDoS attack over AP. The next section highlights the working of attack tools used in performing DDoS attacks. Various DDoS tools have been widely exploited to render DDoS attacks and facilitate attackers to carry out dangerous attack on target; here target may be network resources, server resources, or applications. The fourth section focuses on the state-of-the-art for detection and mitigation approaches of DDoS attacks. Detection approaches are classified into statistical, policy, and machine learning-based approaches. DDoS mitigation OF switches, including Alcatel Lucent’s OmniSwitch, Brocade’s MLXe series routers, and applications such as DefensePro by Radware that are available in market; also depend on the statistical threshold to detect the DDoS attack. In addition, this section also incorporates a brief analysis of the previous defense mechanism of the last 10 years and analyzes and compares the products of different security vendors like Cloudflare, Radware, Akamai, Arbor, Nexusguard, etc.

It is Software defined networking (SDN) is a new network approach which allows separation of the forwarding plane from the control plane in network architecture, that aids in the efficient control of data flow and gives network administrators a software- based method for managing and configuring the networks. In contrast to SDN, which provides a centralized controller, traditional network topologies require the individual configuration of each network device. Due to a centralized control functionality, SDN is increasingly used by businesses, telecom service providers, cloud providers, and many other users, as it encourages flexibility and scalability in the network while also assisting in streamlining operations. There is significant demand of SDN for effective and adaptable networks. SDN adoption has also been rising in the campuses and corporate sectors. This paper provides a concise overview of the Software Defined Networks (SDN) topic, which is essential for comprehending the fundamental principles of SDN in order to conduct research and implement SDN in many sectors. The initial focus is on the discussion of traditional networks, including their limitations, as well as the many issues encountered by industries. The topic of Software Defined Networks is explored, encompassing their necessity, historical background, architectural structure, interfaces, and models. Next, the many applications of Software-Defined Networking (SDN) are examined. Additionally, the various SDN case studies, vendors, setup issues with SDN, and current research fields were elucidated. The discussion focuses on the role of Software-Defined Networking (SDN) in Artificial Intelligence (AI), specifically addressing the issues associated with implementing SDN in AI.

The software defined networks (SDN) is a new network paradigm that supports logical central control. For the failure recovery in SDN, most existing research mainly addressed single failure scenario or single flow rerouting. However, considering multi-failure scenario and multi-flows rerouting is closer to the real SDN environment. Since SDN architecture has a communication bottleneck between the controller and switches, flow rule plays an importance role in their communication. Thus, in this paper, we concentrate on minimizing flow rules for rerouting multi-flows when network occurs multiple link failures, named RMFWMF. We first propose a model to metric the communication overhead between controller and switch during flow rerouting. Next, we formulate the problem as a 0-1 nonlinear programming model, show it can be transformed into a 0-1 linear programming and solve the model using decomposition based on Lagrange relaxation. At last, we implement an experiment in a test network. The result shows that our solution can avoid link congestion in the post-recovery network and can provide the minimum flow rules compared with the pervious algorithm.

Fault-tolerance, survivability and resiliency in wide area networks have long been prominent research topics. With the popularity of the cloud service model and the novel software defined networking (SDN) paradigm, there is renewed interest in failure protection and restoration in network service provisioning. In this work, we propose a novel protection and restoration based virtual network management scheme to enhance fault tolerance in infrastructure-as-a-service, deployed over networked cloud infrastructure. The networked cloud infrastructure is composed of multiple geographically distributed datacenters that are interconnected with SDN. Both compute and network resources are allocated by formulating the virtual network embedding problem as an integer linear program. A shared backup virtual link protection mechanism and a reactive traffic engineering network failure restoration algorithm are proposed and integrated with the framework to provide recovery from unexpected link failures. We implemented the framework on an emulated SDN testbed and evaluated the performances of the algorithms during single and multiple link failures. Experimental results demonstrate trade-offs of the proposed approaches and their applicability in different application scenarios.

PRIMARY RETICULUM CELL SARCOMA OF THE LUNG WITH ENDOBRONCHIAL INVOLVEMENT. CASE REPORT.

Software defined networks (SDN) has gained a lot of attention from both academia and industry recently. SDN is a new networking paradigm that decouples the control plane from the data plane. In this paradigm, control functions are centralized in an SDN controller. The migration from traditional networks to SDN is highly challenging for network operators. Sudden migration may not be possible due to the cost and operational issues. Therefore, incremental deployment of SDN is considered as a viable solution, resulting in the formation of hybrid SDN networks. An important task in hybrid SDN networks is bandwidth allocation and routing considering the coexistence of both conventional and SDN-enabled routers. In this paper, we first formulate this problem as a multi-objective integer program with delay and capacity constraints. Then, a heuristic approach is proposed to combat the computational complexity of the model. Our proposed method is extensively analyzed through simulations, and the evaluation results confirm the effectiveness of our approach.

Software Defined Networking (SDN) has a potential to address a number of networking challenges, but still presents other financial and business challenges such as budget constraints, acceptability and trust amongst network operators. A hybrid SDN deployment is a conceivable solution, because it offers the benefits of SDN and traditional network capabilities, including budget constraints adaptability, falling back on time-tested traditional tools, central network programmability and will offer an organization a smooth transition to SDN. As modern-day communication has become an imperative feature of day to day business functions, there is a need to balance the network load to achieve improved network performance, minimizing delay and reduce the time taken for network response. In this paper, we develop and study multi-path load balancing in a hybrid SDN data plane. The load balancer’s performance is tested using four different hybrid SDN topologies, namely, Fat Tree, Ring, Mesh and Torus topology with the OpenDayLight controller. The main contribution of this work is a data plane congestion and link overloading load balancing testing and analysis for deployment (before or after network failure) in hybrid SDN environments. The obtained results display an improved overall network performance and reduced network delay.

The highly development of Mobile Cloud Computing (MCC) expose many limitations and critical challenges to traditional host-centric IP networks. This paper presents the design of Software-Defined Service-Centric Networks (SD-SCN) to facilitate the networking requirement of MCC. SD-SCN provides a service-level abstraction of communication endhosts to enable name-based routing and explores recent emerging Software-Defined Networking (SDN) concept to enable service-oriented customizable network management. We illustrate some significant benefits taken by SD-SCN to MCC.

Rarely the interest in a new networking paradigm has increased at such a velocity as it is happening for software defined networking (SDN). Motivations of this hype of interest are several but the most important can be re-conducted to the following three: (i) SDN simplifies network configuration and management; (ii) SDN makes the network evolvable; (iii) SDN frees operators from vendors' lock-in. Eagerly, in some cases, or reluctantly, in others, both operators and manufacturers of communication and networking equipments have started new lines of research, development, and marketing focused on SDN. A quick look at the list of members of the organizations promoting the development of SDN-related standards suffices to understand that players of the wireless domain are trying to ride this wave as well. However, it is difficult for the observers to understand where such a wave is headed to in very common networking scenarios involving infrastructureless wireless communications. This paper is an attempt to fill this gap. In fact, a major objective of this paper is to analyze (i) what are the advantages of SDN in infrastructureless wireless networking environments such as wireless personal area networks (W-PANs), and (ii) what are the requirements that must be satisfied to apply SDN in W-PANs. Furthermore, a complete SDN solution for W-PANs, named Software Defined Wireless Network (SDWN), is introduced and a prototype implementation is described.