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Given two sets of vertices V and W, where each vertex in V covers a subset of W, the multi-vehicle covering tour problem asks to determine a number of vehicle routes on a subset of V so as to minimize the total distance under the constraint that every vertex in W must be covered by vertices in the routes. We propose an iterated local search algorithm that features two procedures to improve solutions: one consists of three operations to remove or insert vertices from or into a route; the other is path reconstruction that replaces a partial path with an optimal one, for which we propose a dynamic programming algorithm. We also propose efficient methods to reduce the computation time to search for improved solutions in neighborhoods. The computational results on benchmark instances show that our algorithm performs better than existing methods and is efficient for large-scale instances.

Network management system (NMS) is important to ensure security and efficiency of network. Traditional NMS usually adopts SNMP as management protocol and has achieved great success. However, with emerging of various services, traditional network exposes shortcomings. Software-Defined Network (SDN) is a new paradigm which separates the control plane from the forwarding plane as opposed to the distributed control of current networks. This centralized architecture can simplify the complexity of network management. Although SDN has many advantages, it still lacks mature management tools and is difficult to realize full deployment, which makes network operators reluctant to completely replace their legacy NMS. As a result, it is necessary to combine traditional NMS with SDN. This paper presents the design of SDNMP, which is an approach for managing SDN using traditional NMS. To verify our approach, we build and implement a prototype in our own testbed. By deploying virtual networks and services, results show that SDNMP works well in practice.

The two-dimensional strip packing problem arises in wide variety of industrial applications. In this paper, we focus on the bitmap shape packing problem where a set of arbitrary shaped objects represented in bitmap format should be packed into a larger rectangular container without overlap. The complex geometry of bitmap shapes and large amount of data to be processed make it difficult to check overlaps. For this reason, most of the algorithms in the literature only deal with small-scale instances. We propose an efficient method for checking overlaps and design efficient implementations of two construction algorithms, which are based on the bottom-left strategy. The computational results for a series of well-known benchmark instances show that the proposed algorithms obtain good solutions in remarkably short time and are effective for large-scale instances.

Content-Centric Networking (CCN) is a novel architecture that has been proposed as a solution for dealing with various problems obsessing the Internet, such as the excessive bandwidth costs that result from peer-to-peer (P2P) traffic and content delivery networks (CDN). CCN names packets rather than end-hosts, and most of CCN's characteristics are the consequences of this fact. However, the current design of CCN has some limitations in traffic control, especially in flow fairness and node-to-node collaboration. To solve this problem, we propose an SDN-based autonomie system as the control plane to supplement CCN traffic management. Correspondingly, in the data plane, we utilize a multiprotocol switch to support CCN protocol, flow-aware content delivery and traffic control. We also discuss the implementation and extension issues, and finally, we demonstrate our hybrid scheme to perform centralized and intelligent traffic management, which provides higher awareness, fairness, and low congestion.

Software Defined Networking (SDN) is an emerging networking paradigm that assumes a logically centralized control plane separated from the data plane. Despite all its advantages, separating the control and data planes introduces new challenges regarding resilient communications between the two. That is, disconnections between switches and their controllers could result in substantial packet loss and performance degradation. To achieve resilient control traffic forwarding, this paper investigates the protection of control traffic in SDNs with multiple controllers. We propose a control traffic protection scheme that combines both local rerouting and constrained reverse forwarding protections. This scheme enables switches to locally react to failures and redirect the control traffic to controllers by using standby backup forwarding options. Our goal is then to find a set of primary routes for control traffic, called protection control network, where as much control traffic as possible can benefit from the proposed protection scheme. We formulate the protection control network problem and develop an algorithm to solve it. Simulation results on real topologies show that our approach significantly improves the resilience of control traffic.

By separating the control and forwarding planes, Software-Defined networking (SDN) enables the forwarding paths to be flexibly controlled by the logically centralized controllers using the global network view. To introduce SDN into existing networks, it is necessary to upgrade traditional devices to SDN- enabled ones. However, due to the business, economic and management limitations, it is difficult to realize full SDN deployment. As a result, how to migrate existing devices to SDN-compliant ones becomes the obvious dilemma for every network operator. In this paper, we address this question from the network performance perspective, and study how to leverage the capability of SDN to maximize traffic flow that can be achieved in hybrid SDNs. We formulate the maximum flow problem in networks with partial SDN deployment, and develop a fast Fully Polynomial Time Approximation Scheme (FPTAS) for solving it. Simulation results using real topologies show that hybrid SDNs outperform traditional networks, and we can obtain a near optimal network performance when 50% of SDN nodes are deployed.

Software-Defined Networking (SDN) is a new paradigm, which emerged in the innovation for future networks and has been successfully applied in many scenarios including Campus/Enterprise network and Data Center network. By extending the concept of SDN and autonomicity to the design of versatile network infrastructures, especially to the design of a carrier grade network, we propose AMA, which is an autonomic management architecture for SDN-based multi-services network. AMA is designed and implemented by utilizing autonomic management and network virtualization technologies. We believe that AMA can support more application types, and can be used to build a more flexible network.

Software Defined Networking (SDN) has already gained enormous momentum in the industry. Its innovative architecture that separates the control and forwarding planes allows third-party software developers more leeway in controlling network behavior. Since new protocols and forwarding schemes are needed to produce better network performance, efforts have been put forth in redefining user-defined protocol support. Besides, the concept of autonomicity has been proposed recently to solve the dilemma of management in complex network environments. In this paper, we propose the design and implementation of PindSwitch, which provides a SDN-based Protocol-independent platform to allow users to outline their own protocols' format and flow processing rules into physical switches. We also introduce autonomicity and self-∗ attributes into SDN by extending the architecture of GANA to achieve better management of user-defined protocols and their processing schemes.

In the discussion about Future Internet, Software-Defined Networking (SDN), enabled by OpenFlow, is currently seen as one of the most promising paradigm. While the availability and scalability concerns rises as a single controller could be alleviated by using replicate or distributed controllers, there lacks a flexible mechanism to allow controller load balancing. This paper proposes BalanceFlow, a controller load balancing architecture for OpenFlow networks. By utilizing CONTROLLER X action extension for OpenFlow switches and cross-controller communication, one of the controllers, called “super controller”, can flexibly tune the flow-requests handled by each controller, without introducing unacceptable propagation latencies. Experiments based on real topology show that BalanceFlow can adjust the load of each controller dynamically.