Abstract

Software Defined Networks (SDN) have become a new way to make dynamic topologies. They have great potential in both the creation and development of new network protocols and the inclusion of distributed artificial intelligence in the network. There are few emulators, like Mininet, that allow emulating a SDN in a single personal computer, but there is lack of works showing its performance and how it performs compared with real cases. This paper shows a performance comparison between Mininet and a real network when multimedia streams are being delivered. We are going to compare them in terms of consumed bandwidth (throughput), delay and jitter. Our study shows that there are some important differences when these parameters are compared. We hope that this research will be the basis to show the difference with real deployments when Mininet is used.Keywords: Multimedia delivery; Multimedia streaming; Software Defined Networks (SDNs); Mininet.www.macrothink.org/npa 37 Network Protocols and Algorithms ISSN 1943-3581 2015 IntroductionDue to the substantial improvement in terms of hardware and software for computer networks and also the number of network devices available around the world, the interconnections of devices as well as the network complexity have increased. This fact has also enhanced the way we currently process the information transmitted through the network. Over the past 30 years, the Internet Engineering Task Force (IETF) has developed and built around 5500 Request for Comments (RFC) [1]. Nowadays, Internet and other networks are able to offer huge amount of functionalities suited to the requirements of users.In general, network devices perform two main functions, i.e., the transport function and the control function. On the one hand, the transport function (data plane) that is in charge of sending data through the routes previously calculated. This function is normally performed by specialized circuits known as Application Specific Integrated Circuits (ASICs). The control function (control plane) manages the transport operation thanks to the exchanged information between network devices and the calculation of optimal routes. This allows each device to independently treat the traffic. Network administrators have available few resources to manage and increase the efficiency of the data flows.A professional of networks often finds a big challenge the fact of configuring a network and installing the needed network elements to work properly. Due to the services and the features required by the applications currently require, it is possible to increase the network efficiency if we try to manage jointly the entire network. In this way, there appears the need of developing a new technology to reduce the costs and increase the efficiency by automating policy-based flows.Software-Defined networking (SDN) is a new approach for designing, building, and managing networks that separates the network's control and forwarding planes of a better network optimization [2]. The SDN architecture decouples the netw...

Abstract-In recent years, approaches to control performance and resource optimization for embedded control systems have been receiving increased attention. Most of them focus on theory, whereas practical aspects are omitted. Theoretical advances demand flexible real-time kernel support for multitasking and preemption, thus requiring more sophisticated and expensive software/hardware solutions. On the other hand, embedded control systems often have cost constraints related with mass production and strong industrial competition, thus demanding low-cost solutions.In this paper, it is shown that these conflicting demands can be softened and that a compromise solution can be reached. We advocate that recent research results on optimal resource management for control tasks can be implemented on simple multitasking preemptive real-time kernels targeting low-cost microprocessors, which can be easily built in-house and tailored to actual application needs. The experimental evaluation shows that significant control performance improvement can be achieved without increasing hardware costs.

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Recent trends in distributed embedded systems, such as those found in avionics and trains, have shown an in crease in the amount and heterogeneity of the iriforma tion that needs to be exchanged, together with a growing importance of supporting dynamic reconfiguration and adaptive behaviors. In this paper we focus on Ethernet technologies with real-time reconfiguration support and we address the case of middle-size networking infrastruc tures with a few switches. We use the FTT-SE proto col with the needed adaptations to support dynamic het erogeneous real-time transactions in multi-hop networks. The paper presents a worst-case response-time analysis that provides timeliness guarantees, improving the results obtained with another previous analysis, decreasing the needed network capacity for guaranteed schedulability by 25% on average. Practical experiments and simulation results validate the proposed approach and analysis.

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