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Software-defined networking (SDN) is a modern paradigm leveraging software programmability to enhance communication networks, garnering significant attention and undergoing substantial development due to its diverse applications. One key challenge in SDN lies in managing increasing traffic while avoiding flow table overflow, particularly due to the limited capacity of Ternary Content Addressable Memory (TCAM) in OpenFlow switches. This paper presents a Systematic Literature Review (SLR) that analyzes various approaches to defending against flow table overflow in SDN. Employing a structured approach, we sift through a substantial corpus of research, distilling it into 44 noteworthy articles published from 2015 to the present. We provide an overview of strategies to mitigate flow table overflow attacks, including eviction strategies, dynamic timeout mechanisms, flow rerouting, and aggregated flow entries. Additionally, we analyze mitigation approaches based on deployment strategies, testbed environments, and traffic generation methods. In conclusion, we identify research gaps and challenges, laying the groundwork for future investigations in this domain. [ABSTRACT FROM AUTHOR]

According to Cisco’s Internet Report 2020 white paper, there will be 29.3 billion connected devices worldwide by 2023, up from 18.4 billion in 2018. 5G connections will generate nearly three times more traffic than 4G connections. While bringing a boom to the network, it also presents unprecedented challenges in terms of flow forwarding decisions. The path assignment mechanism used in traditional traffic scheduling methods tends to cause local network congestion caused by the concentration of elephant flows, resulting in unbalanced network load and degraded quality of service. Using the centralized control of software-defined networks, this study proposes a data center traffic scheduling strategy for minimization congestion and quality of service guaranteeing (MCQG). The ideal transmission path is selected for data flows while considering the network congestion rate and quality of service. Different traffic scheduling strategies are used according to the characteristics of different service types in data centers. Reroute scheduling for elephant flows that tend to cause local congestion. The path evaluation function is formed by the maximum link utilization on the path, the number of elephant flows and the time delay, and the fast merit-seeking capability of the sparrow search algorithm is used to find the path with the lowest actual link overhead as the rerouting path for the elephant flows. It is used to reduce the possibility of local network congestion occurrence. Equal cost multi-path (ECMP) protocols with faster response time are used to schedule mouse flows with shorter duration. Used to guarantee the quality of service of the network. To achieve isolated transmission of various types of data streams. The experimental results show that the proposed strategy has higher throughput, better network load balancing, and better robustness compared to ECMP under different traffic models. In addition, because it can fully utilize the resources in the network, MCQG also outperforms another traffic scheduling strategy that does rerouting for elephant flows (namely Hedera). Compared with ECMP and Hedera, MCQG improves average throughput by 11.73% and 4.29%, and normalized total throughput by 6.74% and 2.64%, respectively; MCQG improves link utilization by 23.25% and 15.07%; in addition, the average round-trip delay and packet loss rate fluctuate significantly less than the two compared strategies. [ABSTRACT FROM AUTHOR]

Software-defined networking makes forwarding devices easier to manage and provides centralized control. Because of the centralization, a network administrator can programme the devices cheaply. Network administrators make attempts to convert their entire network into SDN-compatible switches. A good balance of SDN and legacy switching functions can lead to a successful network scenario in network architecture. In this study, a hybrid network scenario is provided in which the external boundary forwarding devices of the service provider network are replaced with SDN devices. Still, the other internal forwarding devices continue to operate traditionally. The benefits of both SDN and legacy network design are combined, allowing the network administrator to reap the benefits of both. The network architecture employs a policy-based routing algorithm that takes advantage of free IP addresses from the free IP pool. The technique enables efficient use of available flow table space, which is critical in SDN architecture due to the small flow table size. The algorithm’s efficiency is assessed using performance metrics such as network path stretch, throughput, latency delay, and so on, compared to traditional SDN controllers such as OpenDayLight, NOX, and POX. According to the experimental results, the suggested approach outperforms specific similar state-of-the-art techniques in the hybrid SDN domain.

The smart grid (SG) is an integration of a traditional power grid with advanced information and communication infrastructure for a large number of electrical applications. Despite all these advantages that the SG will bring, certain issues arise when designing a high-quality SG communication network. One of the critical challenges is that the existing routing strategies in smart power grids are incapable of guaranteeing differentiated QoS requirements considering the network dynamics. To address this limitation, we propose an SDN routing algorithm called the QoS-guaranteed and congestion-controlled OpenFlow routing strategy (QCORS) to satisfy the various communication demands by utilizing the flexibility of SDN. Gaining from its open and programmable idea in SDN, the proposed strategy is expected to divide the link into different congestion levels based on predicting the future congestion status from transmission links. Then packets are expected to be transmitted to routers through links under lower load conditions. The simulation results have demonstrated that the proposed method can reduce the average peer-to-peer delay of all the vocational flow and guarantee the reliability of the network. [ABSTRACT FROM AUTHOR]

Summary: As the policies of a software‐defined networking (SDN) network can be updated dynamically and often at a high pace, conflicts between policies can easily occur. Due to the large number of switches and heterogeneous policies within a typical SDN network, detecting those conflicts is a laborious and challenging task. This article presents three main contributions. First, we devise an offline method for detecting unmatched OpenFlow rules, that is, rules that are never fired. In our taxonomy such anomalies can stem from either invalid or irrelevant unmatched rules. Second, we introduce a new set of definitions for the intraanomalies between rules in the same table, which might occur when using the multiaction feature of an OpenFlow rule. Third, our detection method has been enhanced to support parallel execution, which makes it a viable solution for troubleshooting large‐scale networks. We provide some comprehensive experimental results based on both synthetic and real‐life setup the synthetic set up is designed in such a way that the rule matching takes place in the last rules of the switch and thus putting more stress on the rule detection process. The parallel method is shown to outperform the single‐threaded checking method by order of magnitude up to 21. [ABSTRACT FROM AUTHOR]

The smart grid (SG) is an integration of a traditional power grid with advanced information and communication infrastructure for a large number of electrical applications. Despite all these advantages that the SG will bring, certain issues arise when designing a high-quality SG communication network. One of the critical challenges is that the existing routing strategies in smart power grids are incapable of guaranteeing differentiated QoS requirements considering the network dynamics. To address this limitation, we propose an SDN routing algorithm called the QoS-guaranteed and congestion-controlled OpenFlow routing strategy (QCORS) to satisfy the various communication demands by utilizing the flexibility of SDN. Gaining from its open and programmable idea in SDN, the proposed strategy is expected to divide the link into different congestion levels based on predicting the future congestion status from transmission links. Then packets are expected to be transmitted to routers through links under lower load conditions. The simulation results have demonstrated that the proposed method can reduce the average peer-to-peer delay of all the vocational flow and guarantee the reliability of the network.

Software defined networking (SDN) has been proposed for improving network flexibility and programmability by decoupling control plane and data plane of the network. In SDN, the conflicts between rules need to be avoided, while the partitions of the packet headers need to be precomputed from the configuration rules for the network verification tools. Previous researches usually use the trie-based method and the exhaustive searching with BDD expression to partition the equivalent packet classes (ECs). In this letter, we describe PreChecker to dynamically identify the conflicting rules and divide the rules into ECs. The conflicts between rules are defined for the discrimination of intra-switch conflicts. The MTBDD-based algorithm is proposed for effectively partitioning ECs when updating rules. Both analysis and simulations demonstrate the validity and the better performance of the algorithm. [ABSTRACT FROM AUTHOR]

Due to the increase in the number of users on the internet and the number of applications that is available in the cloud makes Data Center Networking (DCN) has the backbone for computing. These data centre requires high operational cost and also experience the link failures and congestions often. Hence the solution is to use Software Defined Networking (SDN) based load balancer which improves the efficiency of the network by distributing the traffic across multiple paths to optimize the efficiency of the network. Traditional load balancers are very expensive and inflexible. These SDN load balancers do not require costly hardware and can be programmed, which it makes it easier to implement user-defined algorithms and load balancing strategies. In this paper, we have proposed an efficient load balancing technique by considering different parameters to maintain the load efficiently using Open FlowSwitches connected to ONOS controller. [ABSTRACT FROM AUTHOR]

• We propose a SDN control architecture for the optical and wireless convergence. • The architecture dynamically allocates some of the controller's authorities to OLT. • We enhances the disaster response capability by extending the control depth to ONU. • The controller obtains full network information to achieve more flexible control. The optical and wireless convergence technology is one of the principal means for the problem of last mile access. The software-defined network (SDN) supported by OpenFlow protocol is a promising centralized control architecture. Combining these two aspects, we propose a software-defined access network control architecture for the optical and wireless convergence technology, and design its functional modules and the overall interaction process. The proposed architecture adopts the idea of hierarchical control, introduces the OpenFlow agent, dynamically decentralizes some of the controller's authorities to the optical line terminal (OLT), and enhances its overall disaster response capability by extending the control depth of the controller to the optical network unit (ONU). The controller obtains relevant information in real time from a global perspective to achieve more comprehensive dynamic and flexible control, which effectively improves the network resource utilization and meets different service requirements of different users. [ABSTRACT FROM AUTHOR]

In order to use the energy more efficiently, network algorithms and protocols must incorporate in their decision mechanisms some functions focused on saving energy. In this paper we have studied different features and parameters of wireless networks to establish their relationship with the power consumption. First, we have analyzed the variation of power consumption of access points (APs) in function of the antenna transmission power. Second, we have collected user information from real public wireless network to determine the real requirements of network resources in real time basis. Based on this information, a new extension for Openflow protocol over Software-Defined Networking (SDN) networks will be proposed to manage the wireless network, with the aim to keep the optimal network performance with minimal power consumption. This extension introduces new Openflow messages and a new function to be incorporated in SDN controllers and Openflow enabled devices. The proposal will be validated by appropriated simulations based on real scenarios: a shopping center and a municipal wireless network. [ABSTRACT FROM AUTHOR]

The Software Defined Networking (SDN) gained recognition due to its improvements at the packet switching and routing layers. The benefits of programmable, remotely controllable networking devices can be applied to the optical layer of contemporary networks as well. This work introduces CESNET's Czech Light~® family of devices and their role in enabling the SDN approach within the CESNET's production network. As a case study, an upgrade of the Cheb node in CESNET's network from a hard-spliced add-drop multiplexers to SDN-capable Reconfigurable Optical Add-Drop Multiplexers (ROADM) is presented. The upgrade improved operational capabilities of the network, including remote channel equalization, and the possibility to deploy new channels or lambdas without physical intervention. The deployment of ROADM also improved the optical properties of the network.

Traditionally, routers and other network devices encompass both data and control functions in most large enterprise networks, making it difficult to adjust the network infrastructure and operation to large-scale addition of end systems, virtual machines, and virtual networks in industrial comprehensive automation. A network organizing technique that has come to recent prominence is the Software-Defined Network (SDN). A novel SDN based industrial control network (SDNICN) was proposed in this paper. Intelligent network components are included in a SDNICN. Switches in SDNICN provided fundamental network interconnection for the whole industrial control network. Network controller is used for data transmission, forwarding and routing control between different layers. Service Management Center (SMC) is essentially responsible for managing various services used in industrial process control. SDNICN can not only greatly improve the flexibility and performance of industrial control network but also meet the intelligence and informatization of the future industry. [ABSTRACT FROM AUTHOR]

Exponential growth of the Internet, driven most recently by the proliferation of low-cost sensors and IPv6, is mirrored in the growth of networked systems of systems, the tactical Internet of Things. Added to this is our ability and requirement to acquire data from an array of instrumentation at enormous aggregate rates. Radio frequency spectrum continues to diminish as more and more are sold for commercial applications. Testers are faced with mounting challenges--acquiring more data faster, monotonic growth of still and video imagery, compressed timelines for providing results to customers, and the requirement to retain data over longer durations. Test events become larger and more complex, meaning that repeating a test is more costly than ever with more immediate impact to a program. Testers need feedback in near real time about the state of a test and the data being acquired, yet don't have the capacity to transmit all of the data over wireless channels and can't interfere with an ongoing test to harvest storage devices. The solution is to implement an intelligent test network to dynamically manage the instrumentation and limited wireless bandwidth, and push computation to the data using smart instrumentation. [ABSTRACT FROM AUTHOR]

Software-defined networking (SDN) is new network architecture that emerges as to implement network virtualization (NV) with vast features, especially when it is applied it in multi-tenant scenarios. The rapid growth of wireless network applications and services, let to adopt NVs into software-defined wireless network (SDWN). This is because wireless networks require specific features that can be hindered of implementing NVs such as updated location information, dynamic channel configuration, and rapid client re-association. This paper presents state-of-the-art NV methods for SDWN with the aim of highlighting issues and challenges of applying NVs techniques of SDN into SDWN. We discuss three SDN techniques that facilitate NV in the cloud, namely proxy-based virtualization, layer two prefixes-based virtualizations and programing language-based virtualization. Moreover, the paper points out the possibility of providing effective VNs in the SDWN architecture. We also taxonomies the SDWN proposed virtualization methods based on hypervisor controller in the different networks. Finally, the potential requirements and challenges and open issues of SDWN NVs are also identified and presented as the future directions in SDWN research. [ABSTRACT FROM AUTHOR]

Ubiquitous data center optical interconnection between user and data center has become a promising scenario gradually to accommodate high-performance services with end-to-end quality guaranteed. In our previous work, we implemented to provision data center application in inter-data center optical interconnection. In view of this, this study extends to consider the networking relationship between user and data center. We propose a novel software-defined clustered-optical access networking (SD-COAN) architecture for data center services in ubiquitous data center optical interconnection. A cross-stratum flow schedule (CSFS) strategy is introduced for SD-COAN based on the proposed architecture. The SD-COAN can enhance the responsiveness to the dynamic end-to-end data center demands and globally optimize optical access network and application resources effectively. The overall feasibility and efficiency of the proposed architecture are experimentally verified on our OpenFlow-based enhanced SDN testbed. The performance of CSFS strategy under heavy traffic load scenario is also quantitatively evaluated based on SD-COAN architecture in terms of resource occupation rate, average throughput and average provisioning delay, compared with other provisioning strategy. [ABSTRACT FROM AUTHOR]

Virtualization has been widely used in Data Centers, which are running the applications that process data operations or provide services. Migration of virtual machines happens regularly for system load balance, scheduled maintenance, disaster recovery or even in case of unscheduled server downtime. However, packets are still forwarded along the previous path when the migration has completed, which leads to a long time connection interruption and can be abstracted as a consistency problem. We define Connection Recovery Time (CRT) as the duration from the time of migration initiation to the time of reconstructing forwarding rules for migration. In this paper, we analyze the reasons of long CRT in different kinds of Layer-2 switching implementations and propose a novel proactive mechanism to reduce CRT in Software-Defined Network (SDN). Finally, we evaluate the performance of our mechanism, and the CRT in our mechanism can be greatly reduced to the same order of magnitude with general TCP roundtrip time and the occupied hardware resources are hugely reduced. [ABSTRACT FROM PUBLISHER]

Passive optical network (PON) has attracted much attention by the emergence of high-bitrate video-centric applications over the Internet in the access side. In the current commercial PON, the configuration of optical line termination equipment is needed to modify through network management system manually and periodically in the local areas. The traffic flow of different users lacks dynamic control and intelligent schedule. In this paper, we propose and implement a novel software-defined optical access network (SDOAN) architecture for remote unified control based on OpenFlow-enabled PON. Based on the proposed architecture, a service-aware flow scheduling strategy is introduced to flexibly and efficiently allocate the network bandwidth resources and detect the status of network flows in real time. The SDOAN can enhance the resource utilization and QoS guarantee of each user effectively through unified control manner, and reduce the operating expense by remote interaction and operation. We have designed and verified experimentally SDOAN on our test bed with OpenFlow-enabled OLTs. The overall feasibility and efficiency of the proposed architecture are also experimentally demonstrated and compared with interleaved polling with adaptive cycle time strategy in terms of resource occupation rate and average delay. [ABSTRACT FROM AUTHOR]

The Software Defined Networking (SDN) gained recognition due to its improvements at the packet switching and routing layers. The benefits of programmable, remotely controllable networking devices can be applied to the optical layer of contemporary networks as well. This work introduces CESNET's Czech Light~® family of devices and their role in enabling the SDN approach within the CESNET's production network. As a case study, an upgrade of the Cheb node in CESNET's network from a hard-spliced add-drop multiplexers to SDN-capable Reconfigurable Optical Add-Drop Multiplexers (ROADM) is presented. The upgrade improved operational capabilities of the network, including remote channel equalization, and the possibility to deploy new channels or lambdas without physical intervention. The deployment of ROADM also improved the optical properties of the network. [ABSTRACT FROM AUTHOR]

OpenFlow is a Software Defined Networking (SDN) protocol that is being deployed in many network systems. SDN application verification takes an important role in guaranteeing the correctness of the application. Through our investigation, we discover that application verification can be very inefficient under the OpenFlow protocol since there are many race conditions between the data packets and control plane messages. Furthermore, these race conditions also increase the control plane workload and packet forwarding delay. We propose Attendre, an OpenFlow extension, to mitigate the ill effects of the race conditions in OpenFlow networks. We have implemented Attendre in NICE (a model checking verifier), Open vSwitch (a software virtual switch), and NOX (an OpenFlow controller). Experiments show that Attendre can reduce verification time by several orders of magnitude, and significantly reduce TCP connection setup time. [ABSTRACT FROM PUBLISHER]

Network protection against link failure is required to allow packets to reach the destination with minimal packet loss when a failure occurs. When a link fails, traffic that attempts to use the failed link is interrupted. Typically, routers in the network discover the failure and find a new route to bypass the failed link. Alternatively, well-known segment protection schemes can also be used to speed up the link recovery time by rerouting packets locally through precalculated protection paths. However, several backup paths have to be prepared for each primary path, making path configuration rather complex and poorly scalable. This paper proposes a design for fast rerouting in an OpenFlow-based network. This new design reduces the number of flow entries and the number of configuration messages needed for network rerouting, which in turn reduces the memory size needed in each switch and the CPU load at the controller. We show empirically and using simulations that our design can reduce the number of flow entries and configuration messages needed by about 60% and 75%, respectively, when compared with an existing OpenFlow-based segment protection design. Furthermore, we implement the proposed design on a pan-European network and show that our design can recover from a link failure in as little as 25 ms. [ABSTRACT FROM PUBLISHER]