Search

As a new network architecture, Software Defined Network (SDN) has been widely used in recent years. The continuous increase of network scale makes centralized SDN unable to meet network requirements, so distributed SDN comes into being. The application of the optimization algorithm to solve the Controller Placement Problem (CPP) can improve the performance of distributed SDN. The meta-heuristic algorithm has been widely concerned because it is not easy to fall into the local optimal solution. Based on the advantages of meta-heuristic algorithm, this paper uses the multi-point replacement method and the two-point replacement method which have low complexity to discretization African Vultures Optimization Algorithm (AVOA) in the search and development stages respectively to solve CPP in SDN. In addition, the performance of the improved optimization algorithm is compared with other algorithms on three real SDN topologies of different scales. The research results show that compared with other six latest meta-heuristic algorithms, the improved optimization algorithm in this paper can obtain the lowest average delay between the controller and switch in the shortest time. Compared with PHCPA with the best performance, IAVOA proposed in this paper improves the convergence speed of 38.16%. [ABSTRACT FROM AUTHOR] more...

In normal computer networks, the data transmission between two sites go through the shortest path between two corresponding vertices. However, in the setting of software definition network (SDN), it should monitor the network traffic flow in each site and channel timely, and the data transmission path between two sites in SDN should consider the congestion in current networks. Hence, the difference of available data transmission theory between normal computer network and software definition network is that we should consider the prohibit graph structures in SDN, and these forbidden subgraphs represent the sites and channels in which data can’t be passed by the serious congestion. Inspired by theoretical analysis of an available data transmission in SDN, we consider some computational problems from the perspective of the graph theory. Several results determined in the paper imply the sufficient conditions of data transmission in SDN in the various graph settings. more...

Aiming at the problems oflog detection accuracy and long delay of DDoS (distributed denial-of-service) attacks in the software definition networks, this paper proposed a real-time DDoS security system of software definition networks based on kernel functions. Firstly, it abstracted the packet header fields of software definition networks periodly, and formed the abstracted information as matrices; then, it adopted the Mahalanobis distance to analyze the significant change of continuous feature vectors, and it designed two kernel functions to evaluate the behavior flows of attacks; lastly, it identified the attackers by the spectral clustering technique and the covariance statistical information. Experimental results based on the real software definition networks show that the proposed security system realizes a good detection accuracy, and performs a reasonable processing time. [ABSTRACT FROM AUTHOR] more...

In software definition networks, we allow transmission paths to be selected based on real-time data traffic monitoring to avoid congested channels. Correspondingly, this motivates us to study the existence of fractional factors in different settings. In this paper, we present several extend sufficient conditions for a graph admits ID-Hamiltonian fractional (g, f)-factor. These results improve the conclusions originally published in the study by Gong et al. [2]. [ABSTRACT FROM AUTHOR] more...

In order to solve the problem that control and forwarding are closely coupled in traditional network, the network lack of innovation and programmability, and the network management and maintenance difficulty, an SDN load balancing method based on K-Dijkstra is proposed. By using SDN technology to achieve the separation of control and forwarding, the controller is responsible for the global scheduling, making the network flow and task scheduling more flexible than the traditional network. Through the integration of flow management, traffic monitoring, dynamic load balancing and load calculation in the SDN control layer, the K-Dijkstra algorithm and the HRRF algorithm are combined in the load balancing module to solve the problem of path selection. The traffic environment also has a better load balancing effect, optimizing the control layer structure, improving network management efficiency and achieving dynamic load balancing of network traffic. The simulation results on Mininet show that the method can significantly improve network delay, packet loss and throughput compared with traditional networks. [ABSTRACT FROM AUTHOR] more...

Softwares definition network is a new network architecture that achieves a centralized network control. Although centralized control is the main advantage of SDN, but if subject to DDoS attacks,the information will be not reachable,it also likely to cause a single point of failure. In order to mitigate this threat, this paper proposed a DDoS attack detection method based on SDN centralized control. This algorithm obtained the flow table items of OpenFlow switch, analyzed the characteristics of DDoS attacks in SDN environment, and extracted six characteristics related to attacks. By analyzing the changes of the six eigenvalues, it used BP neural network algorithm to classify the training samples to achieve the DDoS attack detection. The experimental results show that the method can improve the recognition rate and reduce the detection time. The effectiveness of the method is verified by the deployment in a software-defined network environment. [ABSTRACT FROM AUTHOR] more...

In the setting of software definition network (SDN), whether there exists an available transmission plan between any two sites is equal to whether there exists a fractional factor after deleting certain vertices and edges in the corresponding graph. A graphGis called a fractional ID-(a, b,m)-deleted graph if after deleting any independent-set I, the remaining graph G - I is a fractional (a, b,m)-deleted graph. A fractional (g, f)-factor F of a graph G is called a Hamiltonian fractional (g, f)-factor if F includes a Hamiltonian cycle. Furthermore, we say that G has a ID-Hamiltonian fractional (g, f)-factor if after deleting any independent set ofGthe remaining graph ofGincludes a Hamiltonian fractional (g, f)-factor. In this paper, we first give a binding number condition for a graph to be a fractional ID-(a, b,m)-deleted graph, and then two sufficient conditions for graphs to have ID-Hamiltonian fractional (g, f)-factors are obtained. [ABSTRACT FROM AUTHOR] more...

Networks continue to grow as industries use both wired and wireless networks. Creating experiments to test those networks can be very expensive if conducted on production networks; therefore, the evaluation of networks and their performance is usually conducted using emulation. This growing reliance on simulation raises the risk of correctness and validation. Today, many network simulators have widely varying focuses and are employed in different fields of research. The trustworthiness of results produced from simulation models must be investigated. The goal of this work is first to compare and assess the performance of three prominent network simulators—NS-2, NS-3, and OMNet++—by considering the following qualitative characteristics: architectural design, correctness, performance, usability, features, and trends. Second, introduce the concept of mutation testing to design the appropriate network scenarios to be used for protocol evaluation. Many works still doubt if used scenarios can suit well to claim conclusions about protocol performance and effectiveness. A large-scale simulation model was implemented using ad hoc on-demand distance vector and destination-sequenced distance vector routing protocols to compare performance, correctness, and usability. This study addresses an interesting question about the validation process: “Are you building the right simulation model in the right environment?” In conclusion, network simulation alone cannot determine the correctness and usefulness of the implemented protocol. Software testing approaches should be considered to validate the quality of the network model and test scenarios being used. [ABSTRACT FROM AUTHOR] more...