OpenFlow Switch Research Articles

An Indirect Controller-Legacy Switch Forwarding Scheme for Link Discovery in Hybrid SDN

Software-defined networking (SDN) has predominantly become the defacto network standard for next generation networking due to its flexibility features; through a single-phase full deployment is unlikely owing to obvious tedious substitution and economic reasons. This has paved the path for hybrid SDN (h-SDN) as a practical alternative with a centralized SDN controller that connects a slow of OpenFlow switches (OFSs) and Legacy switches (LSs). However, such h-SDN imposes fresh challenges since the existing SDN solutions for key functions like topology discovery are rendered futile since LSs do not respond to the controller in the same way OFSs do. State-of-the-art SDN topology protocols, hence, leave out LSs undetected resulting in suboptimal performance. This article presents a novel indirect controller to legacy forwarding (ICLF) scheme that sets out by the controller sending a solitary PACKET_OUT (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ) to an OpenFlow device, which then percolates through the slow of OFSs and LSs; by exploiting the way OFSs and LSs react to the forwarded P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> , the controller can discover the network topology, except for terminal LSs configurations if any. Experiments performed on Mininet shows that the proposed scheme shows an improvement amounted between 34.6%-97.9% in the number of ports detected and reduction in number of messages of about 25%-58.9% under varying degree of legacy device densities, albeit at a slightly overhead of messages forwarded.

Performance analysis of handover delay and buffer capacity in mobile OpenFlow‐based networks

SummarySoftware‐defined networking (SDN) is a network concept that brings significant benefits for the mobile cellular operators. In an SDN‐based core network, the average service time of an OpenFlow switch is highly influenced by the total capacity and type of the output buffer, which is used for temporary storage of the incoming packets. In this work, the main goal is to model the handover delay due to the exchange of OpenFlow‐related messages in mobile SDN networks. The handover delay is defined as the overall delay experienced by the mobile node within the handover procedure, when reestablishing an ongoing session from the switch in the source eNodeB to the switch in the destination eNodeB. We propose a new analytical model, and we compare two systems with different SDN switch designs that model a continuous time Markov process by using quasi‐birth–death processes: (1) single shared buffer without priority (model SFB), used for all output ports for both control and user traffic, and (2) two isolated buffers with priority (model priority finite buffering [PFB]), one for control and the other for user plane traffic, where the control traffic is always prioritized. The two proposed systems are compared in terms of total handover delay and minimal buffer capacity needed to satisfy a certain packet error ratio imposed by the link. The mathematical modeling is verified via extensive simulations. In terms of handover delay, the results show that the model PFB outperforms the model SFB, especially for networks with high number of users and high probability of packet‐in messages. As for the buffer dimensioning analysis, for lower arrival rates, low number of users, and low probability of packet‐in messages, the model SFB has the advantage of requiring a smaller buffer size.

POX Controller and Open Flow Performance Evaluation in Software Defined Networks (SDN) Using Mininet Emulator

Growing popularity of Internet demands for the agility as well as the flexibility of computer networks. Traditional networking system is unable to satisfy recent computing needs. Proprietary devices configured manually create an error-prone situation in addition they are incapable to fully utilize the capability of physical network infrastructure. This has resulted in the paradigm shift in the networking industry and it is known as Software defined networking. Advantages such as programmability, task virtualization and easy management of the network can be provided by employing SDN platform, on the other hand POX is defined as a Python based open source OpenFlow SDN Controller mainly used for faster development and prototyping of new network applications basically comes pre-installed with the mininet virtual machine. POX controller can turn dumb OpenFlow devices into hub, switch, load balancer and firewall devices. In this paper Performance metrics such as service Delay, utilized bandwidth, received packets and bytes were measured and recorded using network monitoring tools like iperf and D-ITG in order to analyze the functionality of the POX controller as well as to evaluate the operation performance of POX controller for SDN environment. The results of this research were the recommendation of using POX controller in for rapid development and prototyping of network control systems as well as being the framework for the interaction with Open Flow switches.

User-Centric Edge Sharing Mechanism in Software-Defined Ultra-Dense Networks

The emerging mobile edge computing (MEC) evolutionarily extends the cloud services to the network edge. In order to efficiently coordinate distributed edge resources, software defined networking (SDN) at the network edge has been explored to realize the integrated management of communication, computation, and cache (3C) resources. However, many research efforts, in software-defined edge networks, are mainly devoted to 1C or 2C resource sharing. Motivated by high service performance and user demands, we propose a user-centric edge resource sharing model for software-defined ultra-dense network (SD-UDN) where multiple MEC servers around small base stations (SBSs) can share their 3C resources through OpenFlow-enabled switches. In particular, the service models of MEC servers and users are formulated to optimize the service process by minimizing the service delay, which is NP-hard. To address this NP-hard issue, a service association model is constructed based on design structure matrix (DSM), and a simulated annealing algorithm is employed to further optimize the service association model for reducing time complexity and offering a nearoptimal solution. Compared with traditional 1C or 2C resource sharing, the proposed edge resource sharing model can guarantee lower service delay for users.

EnFlow: An Energy-Efficient Fast Flow Forwarding Scheme for Software-Defined Networks

In recent years, the huge expansion of Datacenters (DC) to execute billions of end-user applications in real-time leads to a large amount of energy consumption across the globe. So, the traditional TCP/IP-based networks which are being used for DC inter-connections are facing challenges of managing stringent Quality-of-Service (QoS) requirements of different applications of the end-users and service providers. Moreover, the existing solutions rely on distributed architecture and do not scale for large scale data centers. The issue of high power consumption at DC arises with the increase in the number of nodes and links in the network. Also, it becomes problematic on the DC whenever the underlying network resources (switches and routers) are not efficiently utilized at the time of peak data traffic resulting in high operational cost of energy utilization. However, Software-Defined Networking (SDN) emerges as one of the leading technologies to address the aforementioned issues using the programmable switches and controllers. Inspired from these facts, in this paper, we have formulated the Energy-Aware Routing (EAR) problem of DCs as a Mixed Integer Non-Linear Programming (MINLP) for which an Energy-Efficient Fast Flow Forwarding (EnFlow) scheme is designed. The EnFlow scheme uses the power-saving mode of the network to solve the EAR problem. It has three modules namely- priority scheduling, routing, and re-routing. The first module works according to the First-in-First-Out Push Out Priority (FIFO-POP) scheduling using the multiple OpenFlow switches. The FIFO-POP is designed to save the energy usage of multiple switches by reducing the average waiting time of incoming packets in the queue buffers. The second module is based upon an efficient flow re-routing for a new node and link adaptation to provide the maximum bandwidth to the wired links. The third module is based upon the meta-heuristic Ant Colony Routing (ACR) to execute the stochastic decision policy on the network controller for computation of the shortest path of the forwarding nodes. The proposed EnFlow scheme is simulated using the data traces of 34 cities of NorthAmerica zone with Omnet++ 5.1 using various performance evaluation metrics. The results obtained demonstrated that the proposed EnFlow scheme is 24.55% and 71.15% more energy-efficient in comparison to the RE-FPR and ILP-EAR schemes. Also, it consumes 9.72% and 40.83% lower energy in comparison to the FFHA and EXR schemes respectively.

PipeCache: High Hit Rate Rule-Caching Scheme Based on Multi-Stage Cache Tables

OpenFlow switches hardware cannot store all the OpenFlow rules due to a limited resource. The rule-caching scheme is one of the best solutions to solve the hardware size limitation. In OpenFlow switches, Multiple Flow Tables (MFTs) provide more flexible flow control than a single table. Exact match and wildcard match are two typical matching methods. The exact match applies to a single flow table and multiple flow tables, but the performance is low under frequently changing traffic. Many commodity switches use Ternary Content Addressable Memory (TCAM) to support fast wildcard lookups. Earlier works on wildcard-match rule-caching focus on the dependency problem caused by the overlaps of match fields. Their designs cannot handle the rule-caching problem of MFTs because they are based on a single flow table, instead of the widely used MFTs structure. So, we propose a new design named PipeCache that solves the problem of MFTs rule-caching scheme based on wildcard-match. In our design, we logically split the TCAM resources, and assign them to each flow table according to the size of each flow table. Each flow table will cache the selected rules into their assigned TCAM resources and be updated in time by our algorithms to make the most use of the limited TCAM resources. We compare our structure with the exact-match scheme and the wildcard-match scheme based on a single flow table under different cache sizes and traffic localities. Experiment results show that our design PipeCache improves cache hit rate by up to 18.2% compared to the exact-match scheme and by up to 21.2% compared to the wildcard-match scheme based on a single flow table.

Research on Dynamic Migration Technology of OpenFlow Switch

To implement load balance on controllers that are connected to each other in the OpenFlow control plane, we propose a dynamic OpenFlow switch migration algorithm based on attractor selection to solve the e performance bottleneck experienced by a controller when the flow fluctuates on OpenFlow switches. Firstly, we model the problem of the dynamic OpenFlow switch migration. Then, we redefine the parameters of attractor selection based on the switch migration model and propose a dynamic OpenFlow switch migration algorithm based on the attractor selection. Finally, we use the proposed algorithm to determine the destination to the migrated switches to balance the load on the controllers. Simulation results show that the proposed algorithm can guarantee that the load on the controllers is balanced with a low cost.

ISDSDN: Mitigating SYN Flood Attacks in Software Defined Networks

Software defined networking (SDN) has emerged over the past few years as a novel networking technology that enables fast and easy network management. Separating the control plane and the data plane in SDNs allows for dynamic network management, implementation of new applications, and implementing network specific functions in software. This paper addresses the problem of SYN flood attacks in SDNs which are considered among the most challenging threats because their effect exceeds the targeted end system to the controller and TCAM of OpenFlow switches. These attacks exploit the three-way handshaking connection establishment mechanism in TCP, where attackers overwhelm the victim machine with flood of spoofed SYN packets resulting in a large number of half-open connections that would never complete. Therefore, degrading the performance of the controller and populating OpenFlow switches’ TCAMs with spoofed entries. In this paper, we propose ISDSDN, a mechanism for SYN flood attack mitigation in software defined networks. The proposed mechanism adopts the idea of intentional dropping to distinguish between legitimate and attack SYN packets in the context of software defined networks. ISDSDN is implemented as an extension module of POX controller and is evaluated under different attack scenarios. Performance evaluation shows that the proposed mechanism is very effective in defending against SYN flood attacks.

Implementation of Software Defined Networking using Openflow Protocol

Software Defined Networking is a new rising technique that allows to separate the planes. This emerging technology provides agility and flexibility to a network. Agile means the administrator can automatically adjust the network traffic to meet the changing needs. Its main aim is to make the network devices by using software and controlling the networking devices using software. It is attained by using in Mininet software.The SDN is implemented using the OF Protocol in the ONF Software. It is done by using Open flow switch and mainly for accurate communication done by the open flow switch. Here it gives accurate connection and the information is transmitted in the form of packets and delivered correctly to the server or other user, etc., Open flow switch has two types where centralized switch is used here.

NAMP: Network-Aware Multipathing in Software-Defined Data Center Networks

Data center networks employ parallel paths to perform load balancing. Existing traffic splitting schemes propose weighted traffic distribution across multiple paths via a centralized view. An SDN controller computes the traffic splitting ratio of a flow group among all the paths, and implements the ratio by creating multiple rules in the flow table of OpenFlow switches. However, since the number of rules in TCAM-based flow table is limited, it is not scalable to implement the ideal splitting ratio for every flow group. Existing solutions, WCMP and Niagara, aim at reducing the maximum oversubscription of all egress ports and reducing traffic imbalance, respectively. However, the transmission time of flow groups, which measures the quality of cloud services, is sub-optimal in existing solutions that ignore heterogeneous network bandwidth. We propose and implement NAMP, a multipathing scheme considering the network heterogeneity, to efficiently optimize the transmission time of flow groups. Experimental results show that NAMP reduces the transmission time by up to 45.4% than Niagara, up to 50% than WCMP, and up to 60% than ECMP.

Software-Defined Vehicular Cloud Networks: Architecture, Applications and Virtual Machine Migration.

Cloud computing supports many unprecedented cloud-based vehicular applications. To improve connectivity and bandwidth through programmable networking architectures, Software- Defined (SD) Vehicular Network (SDVN) is introduced. SDVN architecture enables vehicles to be equipped with SDN OpenFlow switch on which the routing rules are updated from a SDN OpenFlow controller. From SDVN, new vehicular architectures are introduced, for instance SD Vehicular Cloud (SDVC). In SDVC, vehicles are SDN devices that host virtualization technology for enabling deployment of cloud-based vehicular applications. In addition, the migration of Virtual Machines (VM) over SDVC challenges the performance of cloud-based vehicular applications due the highly mobility of vehicles. However, the current literature that discusses VM migration in SDVC is very limited. In this paper, we first analyze the evolution of computation and networking technologies of SDVC with a focus on its architecture within the cloud-based vehicular environment. Then, we discuss the potential cloud-based vehicular applications assisted by the SDVC along with its ability to manage several VM migration scenarios. Lastly, we provide a detailed comparison of existing frameworks in SDVC that integrate the VM migration approach and different emulators or simulators network used to evaluate VM frameworks’ use cases.

STEREOS: Smart Table EntRy Eviction for OpenFlow Switches

Software-defined networking (SDN) is fundamentally changing the way networks operate, enabling programmable and flexible network management and configuration. As the de facto standard southbound interface of SDN, OpenFlow defines how the control plane interacts with the data forwarding plane. In OpenFlow, flow tables play a significant role in packet forwarding. However, the size of the flow table is limited due to power, cost, and silicon area constraints and capacity-limited tables cannot hold all of the active flows in medium-to-large-scale SDN networks. Thus, when a flow table reaches capacity, an intelligent eviction strategy, which efficiently manages the limited flow table resource, is critical. In this paper, we propose Smart Table EntRy Eviction for OpenFlow Switches (STEREOS), which uses machine learning to classify flow entries as active or inactive and forms the basis for intelligent eviction. Trace-driven simulations demonstrate that STEREOS increases flow table usage by more than 50% and reduces incorrect flow entry evictions by up to 78%, compared with the dominant Least Recently Used eviction policy. Moreover, packet-level simulations of a datacenter network demonstrate that STEREOS can greatly reduce the control overhead, increase overall network throughput by 19%, and reduce packet loss rate by 70%.

Transition to SDN is HARMLESS: Hybrid Architecture for Migrating Legacy Ethernet Switches to SDN

Software-Defined Networking (SDN) offers a new way to operate, manage, and deploy communication networks and to overcome many long-standing problems of legacy networking. However, widespread SDN adoption has not occurred yet due to the lack of a viable incremental deployment path and the relatively immature present state of SDN-capable devices on the market. While continuously evolving software switches may alleviate the operational issues of commercial hardware-based SDN offerings, namely lagging standards-compliance, performance regressions, and poor scaling, they fail to match the cost-efficiency and port density. In this paper, we propose HARMLESS, a new SDN switch design that seamlessly adds SDN capability to legacy network gear, by emulating the OpenFlow switch OS in a separate software switch component. This way, HARMLESS enables a quick and easy leap into SDN, combining the rapid innovation and upgrade cycles of software switches with the port density and cost-efficiency of hardware-based appliances into a fully dataplane-transparent and vendor-neutral solution. HARMLESS incurs an order of magnitude smaller initial expenditure for an SDN deployment than existing turnkey vendor SDN solutions while, at the same time, yields matching, or even better, data plane performance for smaller enterprises.

SDNOFS: Software Defined Networking with Openflow Switches &amp; BCN-ECN with ALTQ for Congestion Avoidance

High-performance computing cluster in a cloud environment. High-performance computing (HPC) helps scientists and researchers to solve complex problems involving multiple computational capabilities. The main reason for using a message passing model is to promote application development, porting, and execution on the variety of parallel computers that can support the paradigm. Since congestion avoidance is critical for the efficient use of different applications, an efficient method for congestion management in software-defined networks based on Open Flow protocol has been presented. This paper proposed two methods; initially, to avoid the congestion problem used by Software Defined Networks (SDN) with open flow switches, this method was originally defined as a communication protocol in SDN environments which allows the SDN controller to interact directly with the forwarding plane of network devices such as switches and routers, both physical and virtual (hypervisor-based), so that it could better adapt to changing business requirements.. Second, to enhance the quality of service and avoid the congestion problem used BCN-ECN with ALTQ. While comparing the existing method, the SDN open flow switches and BCN-ECN with ALTQ provides 98 % accuracy. Usage of these proposed methods will enhance the parameters structures delay time, level of congestion quality time and execution time

A SDN-based active measurement method to traffic QoS sensing for smart network access

Power communication network is very important for the management of the power system. With the exponential growth of the power equipment and the drastic increase in the amount of power monitoring data, there is a huge challenge for the smart network access of the power communication network. Then, software defined network (SDN) which is flexible and scalable is suitable for the power communication network. In order to increase the high quality of service (QoS) of provided communication for users, the traffic QoS sensing is the key of the smart network access in the power communication network. Then, we propose a SDN-Based active measurement method to measure the evaluation parameters of the smart network access in the power communication network. Firstly, we introduce the instructions provided by the OpenFlow protocol, which can be used to collect statistics from OpenFlow switches. Secondly, we define the parameters that should be measured in the power communication network to evaluate the performance of the network and give the corresponding measurement method with them. Next, we proposed a SDN-based active measurement algorithm that updates its measurement interval based on the measurement throughput changes. Finally, we built a simulation platform using the Mininet simulator and the POX controller to verify the proposed measurement method, and the simulation results show the accuracy of our proposed method and the measurement load of our proposed method are both better than that of Polling measurement methods.

Node to Node Performance Evaluation through RYU SDN Controller

Over the last few years, networks became more innovative for constructing and managing with the support of Software Defined Networking (SDN). The inflexibility of typical network architecture gives a great challenge to researchers. SDN is replacing current inflexible and complex networks with an innovative way where the control plane is decoupled from the data plane and fixing some limitations, including manual configuration, debugging, security, scalability, and mobility. Therefore, SDN controllers (e.g., NOX, POX, ONOS, OpenDaylight, Floodlight, Beacon, RYU, etc.) have emerged as a brain to manage such networks. SDN controller’s performance study provides an excellent impact on enhancing the flexibilities and capabilities of an underlying SDN infrastructure network. This paper contextualizes the performance test analysis on the SDN controller is carried out through criterion (e.g., Throughput, Round-Trip Time, etc.). To implement an SDN architecture, this work uses a Mininet emulator containing a controller RYU with switching hub component, one OpenFlow switch, and three nodes. The aim is to evaluate the performance parameters such as Bandwidth, Throughput, Round-Trip Time, Jitter, and Packet loss between nodes using the RYU controller.

Modeling and optimization of packet forwarding performance in software-defined WAN

As a novel network paradigm, Software-Defined Networking (SDN) offers numerous benefits for wide-area networks (WAN), like promoting application performance and reducing deployment costs. However, it also comes along with an inherent penalty to essential network performance such as packet forwarding delay, primarily due to the involvement of logically centralized controllers. This paper is motivated to provide an accurate queueing system of packet forwarding performance in software-defined WAN based on modeling its controller cluster and OpenFlow switches. In particular, we approximate the packet-in message processing of the controller cluster as an M∕M∕n queue based on the derivation of its message arrival process. Meanwhile, we characterize the packet processing of an OpenFlow switch as an M∕G∕1 queue after taking an insight into its packet switching process. As a further step, we build an optimization model of controller cluster deployments to obtain the optimal number of controllers in the cluster. Finally, our proposed queueing model of SDN controller cluster is evaluated with the prevalent benchmark OFsuite_Performance by experiments, and their results indicate that our proposed model provides a more accurate approximation of controller cluster performance. Furthermore, we perform numerical analysis on packet forwarding delay and solve the optimal number of controllers for different varying parameters, which offer effective guidelines for software-defined WAN deployments.

An intelligent flow-based and signature-based IDS for SDNs using ensemble feature selection and a multi-layer machine learning-based classifier

Software-defined networking is a new paradigm that overcomes problems associated with traditional network architecture by separating the control logic from data plane devices. It also enhances performance by providing a highly-programmable interface that adapts to dynamic changes in network policies. As software-defined networking controllers are prone to single-point failures, providing security is one of the biggest challenges in this framework. This paper intends to provide an intrusion detection mechanism in both the control plane and data plane to secure the controller and forwarding devices respectively. In the control plane, we imposed a flow-based intrusion detection system that inspects every new incoming flow towards the controller. In the data plane, we assigned a signature-based intrusion detection system to inspect traffic between Open Flow switches using port mirroring to analyse and detect malicious activity. Our flow-based system works with the help of trained, multi-layer machine learning-based classifier, while our signature-based system works with rule-based classifiers using the Snort intrusion detection system. The ensemble feature selection technique we adopted in the flow-based system helps to identify the prominent features and hasten the classification process. Our proposed work ensures a high level of security in the Software-defined networking environment by working simultaneously in both control plane and data plane.

Performance Analysis and Evaluation of Software Defined Networking Controllers against Denial of Service Attacks

The Software defined networking (SDN) utilization within networking architecture represents a way of looking at how networks are configured, controlled, and operated. Managed services such as routing, load balancing, and security can be automated and centralized dynamically in SDN controllers. Controllers act as the centralized repository of policy and control instructions for the network that packets are transmitted through it. Any transmitted packets flooded from an attacker that intends to access the controller will result to Denial of Service (DoS) attack. Thus, this paper is devoted to simulate and examine the impact of DoS attack on the bandwidth of two different linked hosts (Server/client) by SDN controllers as POX, RYU, and Opendaylight (ODL) controllers. The network performance is tested and emulated by using different testing tools of simulation in Mininet such as Hping3, iperf, jperf, wireshark and miniedit. Also, the performances of the controllers against DoS attack proposed by different protocols using user datagram protocol (UDP) and transmission control protocol (TCP) which will be assess via OpenFlow switch.

An Approach to the Translation of Software-Defined Network Switch Flow Table into Network Processing Unit Assembly Language

This paper considers the OpenFlow 1.3 switch based on a programmable network processing unit (NPU). OpenFlow switch performs flow entry lookup in a flow table by the values of packet header fields to determine actions to apply to incoming packet (classification). In the considered NPU assembly language, lookup operation may be implemented on the basis of search trees. But these trees cannot be directly used for OpenFlow classification because of compared operands width limitation. In this paper, we propose flow table representation designed for easy translation into NPU search trees. Another goal was to create a compact program that fits in NPU memory. Another NPU limitation requires program updating after each flow table modification. Consequently, the switch must maintain the current flow table state to provide a fast NPU program update. We developed algorithms for incremental update of flow table representation (flow addition and removal). To evaluate the proposed flow table translation approach, a set of flow tables was translated into NPU assembly language using a simple algorithm (based on related work) and an improved algorithm (our proposal). Evaluation was performed on the NPU simulation model and showed that our approach effectively reduces program size.