With increasing number of mobile phones and smart devices, it has become hard to manage the networks proactively as well as reactively. Software Defined Networking (SDN) is an emerging technology that promises to solve majority of the challenges faced by the networks in current times. SDN is based on decoupling of data plane and control plane. SDN has a generalized control plane for all networking devices of the network which makes it simple and easy to configure devices on the fly. This paper surveys how Software Defined Networks evolved to be one of the most preferred technology of contemporary times. The architecture and working of all the planes of SDN have been discussed. SDN finds application in variety of areas, some of which have been highlighted in this paper. SDN faces many security threats in each of its planes. The major security challenges are also presented in detail at the end of the paper.

Internet of Things has become a buzzword. It refers to networking of simplest mundane objects not just for human to machine or human to human interactions but for independent thing to thing interaction as well. Such interconnected or smart environment can do wonders but at the same time poses numerous threats to human lives. The ordinary and less powerful objects from day to day life are holding sensitive and private data from humans and trying to transport that through the insecure world of Internet. This new phase of Internet or Internet of Things (IoT) is yet in its infancy and does not have a security support mechanism of its own. The Internet and World Wide Web deal with interconnection of powerful devices like computers or smart phones and are well supported by standard Internet protocols ensuring optimum security and protection. The lightweight versions of the existing Internet protocols are backing the operations of IoT to a large extent but the security needs are not met completely as of yet. Many research organizations and individual researchers are working to make existing protocols and infrastructure applicable in IoT. This paper highlights the threats posed by uncontrolled proliferation of Internet of things and discusses major protocols that have been or that are being designed to overcome the security issues raised by Internet of things.

Active networks introduce a new concept to network architecture. Network nodes are capable of executing codes carried by packets which change their state. Active networks provide a flexible networking environment by their programming capabilities. Although active networks have benefitted networking largely, at the same time they pose many security threats due to their complexity. Since active networks have become famous because of programmability but it's increasing flexible nature opens doors to new security risks. Currently research is being conducted to find out the benefits of active networks over the traditional networks and also to cope up with the security risks that active networks pose. The paper focuses on the benefits of active network over the passive network. The objectives and applications of active networks are briefly discussed. The methodologies of deploying active networks are also mentioned. In the latter part the security issues raised by active networks are presented and methods to cope up with them are also briefly discussed.