International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 09 | Sep 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2336 Optical Network System Existence in Optical Network Systems Deepti Sharma 1 , Shailesh Kumar Singh 2 1 Student M.Sc., Monad University 2 Associate Professor K.K University Bihar ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - Communication through optical fibers is determinedly integrated as a part of the worldwide data infrastructure that is for the economic growth and wellbeing of community optical fiber is playing a very crucial role. The optical fibers are the main attraction because of high data rates and large bandwidth which can support large number of users. In this research work, a restoration technique is designed which uses reactive approach to overcome single link failure. This Proposed method uses Dijkstra’s algorithm to find the shortest path between two nodes in a given network and in case of failure of any link on the working link all the adjacent cycles between end nodes of the failed link are determined. From the found adjacent cycles the shortest adjacent cycle is found out which consists of the source and destination nodes of the failed link. Key Words: Optical Networks, Survivability, Link-Disjoint 1. INTRODUCTION These optical fibres are mainly preferred over copper cables because they are not affected by electromagnetic interference. They are also more secure as it is different to tap inside the optical fibres as it requires skilled labour to do so. Because of the numerous advantages of optical fibres these are a dominant technology now days in long haul and broadband communication services [1]. In earlier days when communication was done using copper cables the bandwidth was limited because of the speed of the electronic processing, they were also affected by electromagnetic interference and communication using copper cables were not secure as they were very easy to tap so fibre optic transmission has been well recognized and efforts are to be made to increase the transmission speed. With the explosive growth of internet it has certainly affected the need to provide not only high unparalleled, accelerating demand for bandwidth requirement and speed, but also requires faster networking infrastructure and different technologies [2- 3]. Optical networks are high capacity telecommunication networks which use information in the form of light to penetrate through if by using the principle of total internal reflection (TIR). Since light has higher frequencies and shorter wavelengths, large amount of information can be transmitted using optical networks. Optical networks operate at a rate of terabits per second; hence they provide higher bandwidth Very high speed optical networks are required for establishing the next generation broadband data communication systems. A failure in an optical network may result in significant data and revenue loss due to large amount of traffic over optical links [4]. In today’s optical networks, which the rapidly growing optical network the problems like link failure, node failure and failures due to other reasons are increasing and surviving from these kind of failure is very important in an optical network otherwise it can cause the failure of entire network ultimately it will affect the users on the network. On different layers of a network such as the SONET/SDH, WDM, IP and MPL layers survivability can be provided. Even though the higher layers could have their own recovery methods, it is important to make sure of survivability on the WDM layer since the WDM layer has numerous advantages compare to the higher layers i.e. effective utilization of resources, faster recovery time from failure and protocol transparency [5-6]. To protect0the network from failures, survivability0may be provided through protection and restoration0techniques. Protection uses a proactive approach where backup resources are reserved during the time of failure and are only utilized when a failure occurs, while restoration uses a reactive approach where both the end nodes whose link has failed enters in a distributed algorithm after the occurrence of failure to find out an alternative path to restore the network from failure. In protection approach alternative backup paths are reserved at the time of network design and these reserved network resources are only utilized at the time a failure has occurred. The survivability from network failure i.e. the time to overcome network failure is very small but this resource utilization is very low [7]. On the other hand, the restoration approach has better resource utilization between no resources are preserved and after the occurrence of failure network is restored using the current available resources of the network. By using this technique, it can take time to restore a network from failure and the restoration time from failure depends on the time to search the current available using which network can be restored. [8-10] then the adjacent node corresponding to the failed link switches from the failed link to the newly found working link to re-establish the network. After restoration of failed link all adjacent nodes of the failed link update their cycles. Restoration time is also calculated to find time required to restore failed link [11]. The proposed technique is tested in MATLAB by comparing results of proposed technique with existing technique so that improvements can be shown.