OpenFlow Implementation Research Articles

Оценка влияния протокола Openflow на производительность сетевых устройств

A very promising area of computer network technologies is the use of Software Defined Network (SDN). The principles of SDN first emerged in the Stanford and Berkeley research laboratories and are currently being developed as part of the Open Network Foundation consortium and the European project OFELIA. The openness of the OpenFlow standard and the introduction of control logic into a separate controller simplifies the software and hardware of active network equipment, which will allow manufacturers to reduce its cost in the future, and therefore reduce the cost of creating computer networks. Therefore, research in this area is very promising. This work is devoted to the study of the performance of SDN, namely, how the implementation of the OpenFlow protocol affects the quality of data transfer between network devices. Using a single stream, the maximum throughput is estimated. To do this, three experimental installations of a network with different network devices, a switch, a router and an OpenFlow device, as well as a dedicated Linux server with support for the OpenFlow protocol, are assembled. The essence of the experiments is to change the size of packets and the size of the forwarding table to assess the performance of SDN with different network devices. The results of the analysis showed that the implementation of OpenFlow on Linux systems is able to offer very good performance. OpenFlow shows good performance with a large number of threads.

Performance evaluation for SDN deployment: an approach based on stochastic network calculus

The OpenFlow implementations (SDNs) have been deployed increasingly on varieties of networks in research institutions as well as commercial institutions. To develop an OpenFlow implementation, it is required to understand the performance of the network. A few benchmark tools (e.g., Cbench and OFlops) can be used to measure the network performance, while these tools take considerable time to simulate traffic behaviors and generate the required results, therefore extending the development time. In this paper, we present an analytical model, which is based on stochastic network calculus theory, for evaluating the performance of switch to controller. The previous studies show that stochastic network calculus can provide realistic emulation of real network traffic behaviors. Our model is evaluated by using both simulation tool and realistic testbed. The results show the stochastic network calculus based analysis model can realistically measure the network performance of the end-to-end properties between controller and switch.

Implementation of OpenFlow based cognitive radio network architecture: SDN&R

The static conventional network architecture is ill-suited to the growing management complexity and highly dynamic wireless network topologies. Software Defined Radio systems and their extension to cognitive and smart radio are characterized by distinct control loops for management which constantly increase network complexity and management inefficiencies, due to clear-cut between radio and core network management. Adding numerous devices and networks together will constantly increase the management cost, thus hinders scalability. Therefore, a holistic solution to synchronize radio and networks status has an elevated demand. To interconnect these systems and devices together, there is a need for a common management interface. OpenFlow is the first standard interface that enables Software Defined Networking (SDN). It can be rolled out in a variety of networking devices to enable improved automation and management by using common Application Program Interfaces to abstract the underlying networking details. The Software Defined Networking & Radio (SDN&R) framework proposed here has a potential combination between SDN and Radio networks to discover the underlying dynamism in cognitive access networks with integrated radio management. By isolating the control plane from the data plane, SDN&R enables a flexible management framework empowered by end-to-end goals through OpenFlow. In this article, we propose, validate, and evaluate the SDN&R architecture. In doing so, first we implement the OpenFlow enabled cognitive basestations (BSs) on Wireless Open-Access Research Platform. Furthermore, we develop software agents on BSs to provide radio status information to the cognitive control application implemented on the SDN controller. The results verify that the proposed framework in-lines with layer-2 or layer-3 forwarding performance. We claim that this work represents the first successful implementation results which synergizes SDN with Cognitive networks that motivates researchers towards SDN based radio resource management.

Efficient FIB caching using minimal non-overlapping prefixes

The size of the global Routing Information Base (RIB) has been increasing at an alarming rate. As a direct effect, the size of the global Forwarding Information Base (FIB) has experienced rapid growth. This increase raises serious concerns for Internet Service Providers (ISPs) as the FIB memory in line cards is much more expensive than regular memory modules, so frequently increasing this memory capacity for all the routers is prohibitively costly to an ISP. Previous research on Internet traffic indicates that a very small number of popular prefixes receive most of the Internet’s traffic, making “caching” a possible solution to reduce the FIB size. However, FIB caching may cause a cache-hiding problem where a packet’s longest-prefix match in the cache differs from that in the full FIB, and thus the packet will be forwarded to the wrong next hop. Motivated by these observations, we propose an efficient FIB caching scheme that stores only non-overlapping FIB entries into the fast memory (i.e., a FIB cache), while storing the complete FIB in slow memory. Our caching scheme achieves a considerably higher hit ratio than previous approaches while preventing the cache-hiding problem. It can also handle cache misses, cache replacement, and routing updates efficiently. Moreover, we have implemented the proposed caching scheme using the OpenFlow platform, which allows a local or remote route controller to manage routes in the cache. We use real traffic of a regional ISP and a Tier1 ISP to carry out our experiments. Our simulation results show that with only 20K prefixes in the cache (5.28% of the actual FIB size), the hit ratio of our scheme is higher than 99.95%. Our OpenFlow implementation achieves a hit ratio near 99.94%, which approaches the performance of the simulated results.

Collaborative demonstration of optical‐layer service‐differentiation and load‐balancing in intelligent optical network

Optical-layer service-differentiation (Diff-Serv) and load-balancing abilities are achieved by collaborative implementation of OpenFlow (OF) switches and intelligent optical adapt unit (IOAU) prototypes. Experimental demonstration shows that by adapting OF-switches as edge routers, optical-layer Diff-Serv can be realised by mapping services of different priorities into different lightpaths. Thus, optical fibre is service-aware rather than merely a blind pipe. In addition, the load-balancing function of the IOAU can be used to gain reasonable wide area network (WAN) link utilisation. By combining these two abilities, many interesting experimental scenarios and meaningful upper layer applications can be devised.

High-Speed Packet Processing using Reconfigurable Computing

Internet applications, notably streaming video, demand extremely high communication speeds in core networks, currently 100 Gbps and moving toward 400 Gbps and beyond. Data packets must be processed at these rates, presenting serious challenges for traditional computing approaches. This article presents a tool chain that maps a domain-specific packet-processing language called PX to high-performance reconfigurable-computing architectures based on field-programmable gate array (FPGA) technology. PX is a declarative language with object-oriented semantics. A customized computing architecture is generated to match the exact requirements expressed in the PX description. The architecture includes components for packet parsing and editing, and for table lookups. It is expressed in a register transfer level (RTL) description, which is then processed using standard FPGA implementation tools. The architecture is dynamically programmable via custom firmware updates when the packet-processing system is in operation. The authors illustrate the language, tool chain, and implementation results through a practical example involving a 100-Gbps OpenFlow implementation.

Experiences and Challenges in Deploying OpenFlow over Real Wireless Mesh Networks

Wireless Mesh Networks propose a distributed architecture for establishing quickly, scalable, reliable and ease of maintenance multi-hop wireless communications. However, many wireless mesh network technologies lack of high level services such as handoff and mobility management. Meanwhile, the OpenFlow protocol offers a framework for developing high level services over data networks. OpenFlow is an interface for remotely controlling the flow table of switches, routers and access points. It separates the control and data planes of network devices, while supports a centralized architecture for controlling the forwarding of packets. Extending wireless mesh networks with OpenFlow offers many benefits, as the use of high level services like mobility. Nevertheless, this combination introduces challenges regarding the opposition between the centralized control of OpenFlow and the distributed architecture of wireless mesh networks. In this paper we expose our experiences deploying an OpenFlow controller over a wireless mesh network based on the 802.11s standard. First, we describe the scenarios employed in our testbed. Then, we discuss the considerations for each scenario. Finally, we expose our conclusions regarding the OpenFlow's implementation and its capabilities of supporting throughput-dependant services.