Smarter Toll Gate Based on Web Of Things Abstract—The Internet of Things perceives a world where-in the embedded devices are made intelligent and can be uniquely identified in the internet. The communication among these devices is achieved by fully integrating them to the web paving way for the concept of Web of Things. With standards like 6LoWPAN at the network layer and 802.15.4 at the physical layer, applications built over these are made smarter, interoperable, scalable and secure. We present a heuristic approach by which interoperability can be implemented at the application layer addressing the issues in a real-time traffic scenario. A REST based design provides loose coupling and lightweight implementation of web services aiding the role of memory constrained devices in the Web of Things. This paper also enlists an efficient publish subscribe mechanism for event notification among the sensors.
Keywords-6LoWPAN, CoAP, Internet of Things, REST, Sensor, Sensor Network, Web of Things
Internet of Things aims in establishing a unique identity for the things and representing them virtually in the internet. The future of technology will be powered by devices, diminishing in the size of processing units. The data that drives the network is gathered by humans, whose efficiency and accuracy is deemed to be questionable. To solve the problems of incompatibility and isolation in a network of smart things and address the shortcomings from the data gatherers, Cyber Objects (Association of physical objects and their virtual representation)  can be proven to be an optimistic solution. According to , it is expected that over the next decade the number of connected devices could reach more than 50 billion. Integrating the ecosystem of embedded devices (based on the Internet of Things) to the web has led to the origin of Web of Things. Applications can be built upon the smart things using well known web languages and technologies (example HTML, Java Script, AJAX, PHP, and Python). We propose an enhancement based on Web of Things for Toll Gate system in specific to the Indian Scenario. The proposed system uses 6LoWPAN at the network ideal for a wireless embedded internet and CoAP at the application layer (see Section IV). The scheme uses the concept of Smart Objects (microcontrollers with sensors, actuators and communication device). The interaction among these objects is made effective using web services. The RESTful implementation of the services ensures high scalability, security and generality of interfaces.
Web services encourage communication among heterogeneous environments either using SOAP (Simple Object Access Protocol) or REST (Representational State Transfer).SOAP is a XML (Extensible Markup Language) based RPC (Remote Procedure Call) solution while the latter is a much more lighter solution. Although SOAP offers support for reliable messaging, security and atomic transactions REST supplants the former by its effective utilization of the well-known HTTP protocol (features like HTTP caching and security enforcement). REST facilitates loose coupling among web services and does not require XML parsing. The application consuming the service needs to understand the format of the information represented which may be of variable formats typically an HTML, XML or JSON document. In environments with limited bandwidth and resources, the RESTful architecture is found to be quintessential . Although REST is light it is not totally suitable for realizing the vision of web of things for the following reasons: •no support for multicast •pull based communication To overcome the above barriers, the IETF (Internet Engineering Task Force) CoRE (Constrained RESTful Environment) Working Group is working on a protocol for embedded web services called CoAP (Constrained Application Protocol) for the application layer. CoAP unlike HTTP works towards building M2M applications. The overhead caused by the use of TCP’s flow control mechanism in HTTP renders it inextensible for the use in resource constrained networks. HTTP is sensitive to mobility and lacks multicast support due to the use of TCP which is overcome in CoAP through the use of UDP. The use of UDP results in compact packet overhead. The architecture we propose for the real-time traffic application involves embedding CoAP based web server on smart things.