Endpoint-transparent Multipath Transport with Software-defined Networks

Multipath forwarding consists of using multiple paths simultaneously to transport data over the network. While most such techniques require endpoint modifications, we investigate how multipath forwarding can be done inside the network, transparently to endpoint hosts. With such a network-centric approach, packet reordering becomes a critical issue as it may cause critical performance degradation. We present a Software Defined Network architecture which automatically sets up multipath forwarding, including solutions for reordering and performance improvement, both at the sending side through multipath scheduling algorithms, and the receiver side, by resequencing out-of-order packets in a dedicated in-network buffer. We implemented a prototype with commonly available technology and evaluated it in both emulated and real networks. Our results show consistent throughput improvements, thanks to the use of aggregated path capacity. We give comparisons to Multipath TCP, where we show our approach can achieve a similar performance while offering the advantage of endpoint transparency

Evaluación comparativa del rendimiento de controladores SDN de código abierto

Software-defined Networking (SDN) constitutes a new era in the development of internetworking. The SDN paradigm splits the data plane from the control plane. It uses controller equipment, which is responsible for centrally managing several network devices simultaneously. This study analyzes three open-source controllers for SDN based on the OpenFlow protocol. Specifically, the performance of FloodLight, OpenDayLight (ODL), and Ryu controllers is evaluated in terms of latency, throughput, and scalability. In doing so, the Cbench tool is used in an emulated environment with Mininet. The results show that the Ryu controller presents the lowest performance in all the evaluated parameters; ODL provides lower latency and FloodLight higher throughput. Regarding scalability, we conclude that Floodlight can be used in small networks, whereas ODL can be used in dense networks. Furthermore, we evaluate their main characteristics, which must be considered for their choice prior to implementation and deployment.Las redes definidas por software (SDN) constituyen una nueva era en el diseño de la interconexión de redes. El paradigma SDN separa el plano de datos del plano de control. Para esto utiliza un equipo controlador, que se encarga de gestionar de forma centralizada varios dispositivos de red al mismo tiempo. Este estudio analiza tres controladores SDN de código abierto basados en el protocol OpenFlow. Específicamente, el rendimiento de los controladores FloodLight, OpenDayLight (ODL) y Ryu son evaluados en términos de latencia, throughput y escalabilidad. Para ello se utilizó la herramienta Cbench en un entorno emulado con Mininet. Los resultados muestran que el controlador presenta un menor rendimiento en todos los parámetros evaluados; ODL tiene una menor latencia y Floodlight un mayor throughput. En lo que tiene que ver a escalabilidad, se concluye que Floodlight es recomendable para redes pequeñas y ODL para redes densas. Además, evaluamos sus principales características, las cuales deben ser tomadas en cuenta para su elección antes de su implementación y despliegue

End-host Driven Troubleshooting Architecture for Software-Defined Networking

The high variability in traffic demands, the advanced networking services at various layers (e.g., load- balancers), and the steady penetration of SDN technology and virtualization make the crucial network troubleshooting tasks ever more challenging over multi-tenant environments. Service degradation is first realized by the users and, as being the only one having visibility to many relevant information (e.g., connection details) required for accurate and timely problem resolution, the infrastructure layer is often forced upon continuous monitoring resulting in wasteful resource management, not to mention the long time frames. In this paper, we propose an End-host-Driven Troubleshooting architecture (EDT), where users are able to share the application-specific connection details with the infrastructure to accelerate the identification of root causes of performance degradation, and to avoid the need for always-on, resource-intensive, and network- wide monitoring. Utilizing EDT, we provide some essential tools for real end-to-end trace routing (PTR), identifying packet losses, and carry out hop-by-hop latency measurements (HEL). In contrast to existing proposals, PTR traces the practical production traffic without the need of crafted probe packets by means of careful tagging mechanisms and additional ephemeral capturing flow rules. Besides involving negligible data plane deterioration, in certain cases PTR can drastically reduce the time needed to find a traversed path compared to existing solutions. Finally, by means of individual network functions, HEL measures the latency of each link along the found path without involving the controller into the calculation, hence resulting in significant reduction of control plane overhead

A Queue Monitoring System in OpenFlow Software Defined Networks, Journal of Telecommunications and Information Technology, 2017, nr 1

Real-time traffic characteristic is different and it is very sensitive to delay. To meet traffic specications in real time, monitoring systems are used as an important part of networking. Many monitoring systems are deployed to have an update view of the network QoS parameters and performance. Most of these systems are implemented to measure QoS parameters in links. Here, in this paper, a system for monitoring queues in each link by means of Software Defined Networks is proposed. The monitoring system is implemented by extending Floodlight controller, which uses OpenFlow as southbound protocol. The controller has a centralized view of the network. By the help of OpenFlow it also can provide flow level statistics. Using these advantages, the proposed system can monitor delay and available bandwidth of a queue on a link or path. Despite of monitoring systems in traditional networks, the proposed monitoring system makes a low overhead in network thanks to OpenFlow protocol messages. It is also integrated into the network controller, which enables QoS and trac engineering applications to use the system's reports for automatic traffic management and QoS setup. The experimental results show a 99% accuracy of the proposed system for monitoring of both bandwidth and delay

Developing an asynchronous technique to evaluate the performance of SDN HP Aruba switch and OVS

Developers of Software Defined Network (SDN) faces a lack of or difficulty in getting a physical environment to test their inventions and developments. That drives them to use a virtual environment for their experiments. This work addresses the differences between the SDN virtual environment and physical SDN switches, which leads to equip a more realistic SDN virtual environment. Consequently, this paper presents a precise performance evaluation and comparison of off-the-shelf SDN devices, HP Aruba 3810M, with Open Virtual Switch (OVS) inside Mininet emulator. This work examines the variability of the path delay, throughput, packet losses and jitter of SDN in a different windows size of the packets and network background loads. Our conducted experiments consider a number of protocols such as ICMP, TCP and UDP. In order to evaluate the network latency accurately, a new asynchronous latency measurement technique is proposed. The developed technique shows more precise results in comparison to other techniques. Furthermore, the work focuses on extracting the flow-setup latency, caused by the external SDN controller when setting flow rules into the switch. The comparison of results shows a dissimilarity in the behaviour of SDN hardware and the Mininet emulator. The SDN hardware exposed higher latency and flow-setup time due to extra resources of delay, which the emulator does not possess

Developing an asynchronous technique to evaluate the performance of SDN HP Aruba switch and OVS

Developers of Software Defined Network (SDN) faces a lack of or difficulty in getting a physical environment to test their inventions and developments. That drives them to use a virtual environment for their experiments. This work addresses the differences between the SDN virtual environment and physical SDN switches, which leads to equip a more realistic SDN virtual environment. Consequently, this paper presents a precise performance evaluation and comparison of off-the-shelf SDN devices, HP Aruba 3810M, with Open Virtual Switch (OVS) inside Mininet emulator. This work examines the variability of the path delay, throughput, packet losses and jitter of SDN in a different windows size of the packets and network background loads. Our conducted experiments consider a number of protocols such as ICMP, TCP and UDP. In order to evaluate the network latency accurately, a new asynchronous latency measurement technique is proposed. The developed technique shows more precise results in comparison to other techniques. Furthermore, the work focuses on extracting the flow-setup latency, caused by the external SDN controller when setting flow rules into the switch. The comparison of results shows a dissimilarity in the behaviour of SDN hardware and the Mininet emulator. The SDN hardware exposed higher latency and flow-setup time due to extra resources of delay, which the emulator does not possess

Overcoming Bandwidth Fluctuations in Hybrid Networks with QoS-Aware Adaptive Routing

With an escalating reliance on sensor-driven scientific endeavors in challenging terrains, the significance of robust hybrid networks, formed by a combination of wireless and wired links, is more noticeable than ever. These networks serve as essential channels for data streaming to centralized data centers, but their efficiency is often degraded by bandwidth fluctuations and network congestion. Especially in bandwidth-sensitive hybrid networks, these issues present demanding challenges to Quality of Service (QoS). Traditional network management solutions fail to provide an adaptive response to these dynamic challenges, thereby underscoring the need for innovative solutions. This thesis introduces a novel approach leveraging the concept of Software-Defined Networking (SDN) to establish a dynamic, congestion-aware routing mechanism. This proposed mechanism stands out by comprising a unique strategy of using bandwidth-based measurements, which help accurately detect and localize network congestion. Unlike traditional methodologies that rely on rigid route management, our approach demonstrates dynamic data flow route adjustment. Experimental data indicate promising outcomes with clear improvements in network utilization and application performance. Furthermore, the proposed algorithm exhibits remarkable scalability, providing quick route-finding solutions for various data flows, without impacting system performance. Thus, this thesis contributes to the ongoing discourse on enhancing hybrid network efficiency in challenging conditions, setting the stage for future explorations in this area

Incast mitigation in a data center storage cluster through a dynamic fair-share buffer policy

Incast is a phenomenon when multiple devices interact with only one device at a given time. Multiple storage senders overflow either the switch buffer or the single-receiver memory. This pattern causes all concurrent-senders to stop and wait for buffer/memory availability, and leads to a packet loss and retransmission—resulting in a huge latency. We present a software-defined technique tackling the many-to-one communication pattern—Incast—in a data center storage cluster. Our proposed method decouples the default TCP windowing mechanism from all storage servers, and delegates it to the software-defined storage controller. The proposed method removes the TCP saw-tooth behavior, provides a global flow awareness, and implements the dynamic fair-share buffer policy for end-to-end I/O path. It considers all I/O stages (applications, device drivers, NICs, switches/routers, file systems, I/O schedulers, main memory, and physical disks) while achieving the maximum I/O throughput. The policy, which is part of the proposed method, allocates fair-share bandwidth utilization for all storage servers. Priority queues are incorporated to handle the most important data flows. In addition, the proposed method provides better manageability and maintainability compared with traditional storage networks, where data plane and control plane reside in the same device

Network Security through Software Defined Networking: a Survey

International audienceNetwork security is a predominant topic both in academia and industry. Many methods and tools have been proposed but the attackers are still able to launch massive and effective attacks. Keeping the pace with the new threats appearing or becoming more sophisticated everyday is of a paramount of importance. Software Defined Networking (SDN) has recently emerged and promotes the programmability of the networks, which thus allows to enable in-network security functions. This includes firewalls, monitoring applications or middlebox support through OpenFlow devices. Therefore, this paper reviews the related approaches which have been proposed by identifying their scope, their practicability, their advantages and their drawbacks