Web of Things or Internet of Things (IoT) was an emerging technology where things of everyday objects could be connected to the Internet. Cloud computing is an important technology for IoT. We proposed six levels of IoT architectures with respect to cloud, and these architectures describe the storage, controlling, and monitoring of various sensors and actuators in IoT applications. Better selection of protocols produce better results for constrained IoT environment.In this paper, we analyzed IoT architecture levels with respect to cloud, various IoT applications, and layer wise protocols and proposed two optimized protocol suites named as MQTT protocol suite and CoAP protocol suite. We implemented these protocols in a small IoT application and compared these two suites with respect to transmission delay, number of packets transferred, the overhead due to re-transmission, and the battery power usage. We also proposed optimized suite for some IoT applications with respect to their characteristics. KEYWORDSCloud, CoAP, Internet of Things (IoT), MQTT INTRODUCTIONInternet of Thing is a new revolution of the Internet. Statistics say that, in coming few years, the total number of things or devices connected to the Internet will become 50 billion. These billions of devices or things are being connected to the Internet through the Gateways. In IoT technology, things from the heterogeneous network can communicate and exchange data. These devices include hardware and software components, hubs, or control centers. The IoT technology enables the physical object as an intelligent device, which results the device or thing can visualize, hear, take decisions, and perform actions. The underlying technologies of IoT are WSN, pervasive computing, embedded devices, cloud computing, big data, RFID tags, mobile technology, web, internet protocols, communication technologies, and applications. 1 The Gartner analysis shows that the deployment of interconnected sensor devices is up to 28 billion by 2020. RELATED WORKDatta et al 2 proposed a Machine-to-Machine communication through the wireless gateway. Moreover, this gateway is limited to REST quires in the application layer and provides a dynamic device discovery. Castellani et al 3 proposed a mechanism for M2M communication, but the conversation is limited to only HTTP to CoAP. Desai et al 4 proposed a gateway and Semantic Web enabled IoT architecture, here a complex multi-protocol proxy brings the interoperability of messaging protocols such as XMPP, CoAP, and MQTT. Perez de Almeida et al 5 proposed a service oriented things broker, this broker does provide a restful interface for the smart objects and limited to twitter based communication model. Khan et al 6 proposed three layer architecture consisting of application, network, and perception layer and not described about the feasible protocols for IoT applications. A new technology SDN (Software Defined Networking) have come into the picture and takes an important role for variousIoT communications, 7 but the problem with SDN is tha...

The IoT connects many of the home appliances in the world, from intelligent thermostats to intelligent vehicles. By the end of 2015, we had 9 billion connected stuff. The Gartner forecast shows that the number of devices in the network will exceed 50 billion by 2020. Most of the connected devices in the existing network are based on obsolete security infrastructure and encryption, while many do not have provisions for remote updating of these devices. Taking into account the number of IoT devices, from off-shelf motion monitoring to machine tools, it is not possible to check which functions end up with any specific service or product. In short, this is the problem: you can't trust the integrity of the security of the device and determine exactly where the data is processed and stored. The SDN architecture is designed to increase the routing and networking performance of the existing networks by isolating the control plane from the data plane. The basic concept of Software Defined Networking can be applied to IoT Multi networks; however, the standard SDN implementations for wired networks are not directly suitable for distributed and ad-hoc mesh networks, which are common in IoT systems. However, the SDN architecture changes the pattern of communication of the IoT network, leading to a new approach to the manifestation of the Securities IoT network. Centralized data layer control and control layer not only simplifies data package management, but also increases safety. As mentioned above, the amount of data that flows into these systems is significant. Proper management of traffic and load balancing will help to simplify the data flow in some ways. The total system's power consumption may be reduced by the central station, which requires less power than the distributed control. To sum up, introducing SDN into IoT will help IoT and stimulate IoT in people's regular lives.

A fully automated house must ensure all the appliances must be connection and provide a smart way of working for the human. The insight of Internet of Things (IoT) network provision the necessary platform to implement the automated home. The proposed system emphasizes, how all the appliances would be connected to IoT to ensure fully automated home. In this framework the smart home has been divided into various areas like smart kitchen, smart gardening, home safety and security system, and smart lightning system. The reliable protocol stack has been utilized to provide efficient communication along with proper security measures. The reliable protocol suite works on top of MQTT and TCP to ensure reliable communication. The smart gateway utilized for this framework and provides firewall security as with a two-phase filtering mechanism as well as scalability. among all the appliances in the home.