Network virtualization offers flexibility by decoupling virtual network from the underlying physical network. Software-Defined Network (SDN) could utilize the virtual network. For example, in Software-Defined Networks, the entire network can be run on commodity hardware and operating systems that use virtual elements. However, this could present new challenges of data plane performance. In this paper, we present an empirical model of the packet processing delay of a widely used OpenFlow virtual switch, the Open vSwitch. In the empirical model, we analyze the effect of varying Random Access Memory (RAM) and network parameters on the performance of the Open vSwitch. Our empirical model captures the non-network processing delays, which could be used in enhancing the network modeling and simulation.
S. Azodolmolky @cite_3 developed a network calculus based an analytical model to describe the functionality of Software-Defined Networks. They modeled the behavior of an SDN switch in terms of delay, queue length boundaries, buffer length and controller buffer length. K. Mahmood @cite_10 provided SDN modeling based on queuing theory, where a Jackson network was used to model the data plane and queue was used to model the controller. They determined the average time a packet spends in the SDN and the maximum data that can be injected in the network given some delay requirements. Authors built a custom simulator to validate their analytical model. Another queuing theory based model was developed by Xiong @cite_4 to evaluate the OpenFlow-based software-defined network. To obtain the average time a packet spends in the system, an @math queue was used to model the switch. They evaluated the switch queuing model with different performance parameters using numerical analysis. The queue was used to model the controller packet-in behavior and it was evaluated using widely used benchmark Cbench under various network scenarios.
@cite_4 @cite_10 @cite_3
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OpenFlow is one of the most famous protocols for controller-to-switch communications in software-defined networking (SDN), commonly seen as a promising way towards future Internet. Understanding the performance and limitation of OpenFlow-based SDN is a prerequisite of its deployments. To achieve this aim, this paper proposes a novel analytical performance model of OpenFlow networks based on queueing theory. After depicting a typical network scenario of OpenFlow deployments, we model the packet forwarding of its OpenFlow switches and the packet-in message processing of its SDN controller respectively as the queueing systems MX M 1 and M G 1. Subsequently, we build a queueing model of OpenFlow networks in terms of packet forwarding performance, and solve its closed-form expression of average packet sojourn time and the corresponding probability density function. Finally, the numerical analysis is carried out to evaluate our proposed performance model with different parameter values. Furthermore, our controller model is contrasted with the classical one by utilizing the popular benchmark Cbench. Experimental results indicate that our controller model provides a more accurate approximation of SDN controller performance. OpenFlow (OF) is one of the most widely used protocols for controller-to-switch communication in a software defined network (SDN). Performance analysis of OF-based SDN using analytical models is both highly desirable and challenging. There already exists a very elegant analytical model based on M M 1 queues to estimate the packet sojourn time and probability of lost packets for the case in which a controller is responsible for only a single node in the data plane. However the literature falls short when it comes to the multiple node case, i.e. when there is more than one node in the data plane. In this work we propose a model to address this challenge by approximating the data plane as an open Jackson network with the controller also modeled as an M M 1 queue. The model is then used to evaluate the system in the light of some of the metrics, such as; how much time a packet spends on average in an OF-based network and how much data we can pump into the network given the average delay requirements. Finally the PDF and the CDF of the time spent by the packet in an OF-based SDN for a given path is derived. Software defined networking (SDN) and OpenFlow as the outcome of recent research and development efforts provided unprecedented access into the forwarding plane of networking elements. This is achieved by decoupling the network control out of the forwarding devices. This separation paves the way for a more flexible and innovative networking. While SDN concept and OpenFlow find their ways into commercial deployments, performance evaluation of the SDN concept and its scalability, delay bounds, buffer sizing and similar performance metrics are not investigated in recent researches. In spite of usage of benchmark tools (like OFlops and Cbench), simulation studies and very few analytical models, there is a lack of analytical models to express the boundary condition of SDN deployment. In this work we present a model based on network calculus theory to describe the functionality of an SDN switch and controller. To the best of our knowledge, this is for the first time that network calculus framework is utilized to model the behavior of an SDN switch in terms of delay and queue length boundaries and the analysis of the buffer length of SDN controller and SDN switch. The presented model can be used for network designers and architects to get a quick view of the overall SDN network deployment performance and buffer sizing of SDN switches and controllers.