Application of the “Endless Train” Method for the SDN Controller OpenDayLight

Application of the “Endless train” method for the SDN controller OpenDayLight. Using the cloud for software defined networks opens new possibilities for the organization of computing processes of network controllers. Methods of virtual entities maintenance in a cloud environment allow counting on relatively infinite computing resources of the cloud service called Platform as a Service. Today it is possible to evaluate the degree of utilization of computing resources for the operation of the software controller only theoretically. The article considers the possibility of using an “endless train” method for virtualization of individual functional opportunities of SDN OpenDayLight controller. This method allows to organize controller computer processes caused by the need to serve the dynamically changing stream of user applications, such as initialization of the flow or the organization of virtual networks. In the section “Architecture and basic features SDN controller” the main components and functionality of the controller OpenDayLight were described. The method of “endless train” for the distribution of tasks between virtual machines and possibility of its use for various functions of the OpenDayLight controller were considered in the section “The method of “endless train” for the organization of the computational process SDN”. In the next section “Description of the experiment” the results of simulation modeling of proposed method to study its effectiveness are presented.


Introduction
In recent years a rapid increase in mobile traffic, and change of its structure have been seen. Modern mobile network should be able to support a large number of subscribers and process large amounts of data. They need to create high-performance clusters and well scalable virtualized environment. All these factors lead to an increase in requirements for network environment and it is often the limiting factor in the development of computing infrastructure.
The main problem of today's mobile networks is that they are too static, therefore they do not meet the current dynamics of the allocation process, unlike servers that are required by this virtualization technology [1]. Nowadays applications are distributed between multiple virtual machines that exchange data very intensively (leading to an increase of eastwest traffic, which begins to dominate over traditional client-server north-south traffic). Virtual machines often migrate to optimize the load of servers [2]. It modifies traffic binding points. Traditional addressing scheme, logical separation of networks and methods of appointment rules processing traffic in these dynamic environments become ineffective.
Similar difficulties arise with the reconfiguration mechanisms for Quality of Service (QoS) while adding a new multiservice network application, such as video.
Procedures of security settings modification in large networks take too much time that prevents quickly respond to emerging threats [3]. The purpose of this paper is to describe and to formalize the method which allows to optimize the process of service applications in SDN by increasing the efficiency of the SDN controller work. The algorithm of proposed method of service computing processes in Cloud environments called "endless train"   Platform-as-Infrastructure is an isolated cluster, consisting of a group of servers and services that work together as a complete system, allowing easy deployment, test, maintain and scale the system. PaaS lets you create and maintain an unlimited number of virtual machines whose job is to serve the computing functions of the controller. The use of an unlimited number of resources for virtual machines will avoid periods of reduced quality of service.
The method proposed in this article is called "effect of endless train". Its main idea is that after a certain virtual machine for service received a specified number of tasks, a new virtual machine will be created, which receives all of the following tasks ( fig. 5).
The proposed method is based on the method of dynamic migration of virtual machines, developed by Jelastic [8], which provides server load balancing cloud storage by creating a platform for the automatic control of virtual machine containers. Also considered the method of choice container for migration of virtual machines described in [9], which allows you to analyze and predict the load on the network based on an assessment of resources used.  fig. 6.
Processing Processing Processing -Method of "endless train" was simulated as the system of queuing with unlimited (very high) amount of service devices, each function processed by a separate group of service devices.
During the experiment, the procedure of connection setting for the subscriber that runs by the SDN controller was modeled. The controller is represented as a queuing system. Each of the elements of the controller was presented as a service unit. The scheme of the procedure is as follows: