International Conference on Management, Science, Technology, Engineering, Pharmacy and Humanities (ICM STEP) – 2021 | ISSN: 2349-6002 151527 © June 2021| IJIRT | Volume 8 Issue 1 | www.ijirt.org 187 Software-Defined Networking: Self-Healing Topology Discovery Protocol for Software Defined Networks T. Vamshi Mohana 1 , Dr. Baddam Indira 2 1 Research Scholar, Career Point University 2 Research Supervisor, Career Point University Abstract - Plug-and-play information technology (IT)infrastructure has been expanding very rapidly in recent years. With the advent of cloud computing, many ecosystem and business paradigms are encountering potential changes and may be able to eliminate their IT infrastructure maintenance processes. Real-time performance and high availability requirements have induced telecom networks to adopt the new concepts of the cloud model: software-defined networking (SDN) and network function virtualization (NFV). NFV introduces and deploys new network functions in an open and standardized IT environment, while SDN aims to transform the way networks function. SDN and NFV are complementary technologies; they do not depend on each other. However, both concepts can be merged and have the potential to mitigate the challenges of legacy networks. In this paper, our aim is to describe the benefits of using SDN in a multitude of environments such as in data centers, data center networks, and Network as Service offerings. We also present the various challenges facing SDN, from scalability to reliability and security concerns, and discuss existing solutions to these challenges. Index Terms - Software- Defined Networking, OpenFlow, Datacentres, Network as a Service, Network Function Virtualization. 1.INTRODUCTION Today’s Internet applications require the underlying networks to be fast, carry large amounts of traffic, and to deploy a number of distinct, dynamic applications and services. Adoption of the concepts of “inter- connected data centers” and “server virtualization” has increased network demand tremendously. In addition to various proprietary network hardware, distributed protocols, and software components, legacy networks are inundated with switching devices that decide on the route taken by each packet individually; moreover, the data paths and the decision-making processes for switching or routing are collocated on the same device. This situation is elucidated in Fig. 1. The decision- making capability or network intelligence is distributed across the various network hardware components. This makes the introduction of any new network device or service a tedious job because it requires reconfiguration of each of the numerous network nodes. Legacy networks have become difficult to automate [1, 2]. Networks today depend on IP addresses to identify and locate servers and applications. This approach works fine for static networks where each physical device is recognizable by an IP address, but is extremely laborious for large virtual networks. Managing such complex environments using traditional networks is time -consuming and expensive, especially in the case of virtual machine (VM) migration and network configuration. To simplify the task of managing large virtualized networks, administrators must resolve the physical infrastructure concerns that increase management complexity. In addition, most modern-day vendors use control-plane software to optimize data flow to achieve high performance and competitive advantage [2]. This switch-based control-plane paradigm gives network administrators very little opportunity to increase data-flow efficiency across the network as a whole. The rigid structure of legacy networks prohibits programmability to meet the variety of client requirements, sometimes forcing vendors into deploying complex and fragile programmable management systems. In addition, vast teams of network administrators are employed to make thousands of changes manually to network components [2, 3].