The Constrained Application Protocol (CoAP) is an HTTP-like protocol for RESTful applications intended to run on constrained devices, typically part of the Internet of Things. CoAP observe is an extension to the CoAP specification that allows CoAP clients to observe a resource through a simple publish subscribe mechanism. In this paper we leverage Information-Centric Networking (ICN), transparently deployed within the domain of a network provider, to provide enhanced CoAP services. We present the design and the implementation of CoAP observe over ICN and we discuss how ICN can provide benefits to both network providers and CoAP applications, even though the latter are not aware of the existence of ICN. In particular, the use of ICN results in smaller state management and simpler implementation at CoAP endpoints, and less communication overhead in the network.
Recent efforts @cite_19 @cite_21 have been performed on proxy based CoAP observe in Wireless Sensor Network (WSNs). Alessandro et el. @cite_19 includes WebSocket protocol in the design of the CoAP proxy for HTTP based web applications. The work in @cite_23 considers dynamic aggregation scheduling of multiple observe requests at CoAP proxies. These efforts are complementary to our work, which utilizes ICN to further enhance the efficiency gains of the CoAP observe.
@cite_19 @cite_21 @cite_23
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In this paper, we present the design of a Constrained Application Protocol (CoAP) proxy able to interconnect Web applications based on Hypertext Transfer Protocol (HTTP) and WebSocket with CoAP based Wireless Sensor Networks. Sensor networks are commonly used to monitor and control physical objects or environments. Smart Cities represent applications of such a nature. Wireless Sensor Networks gather data from their surroundings and send them to a remote application. This data flow may be short or long lived. The traditional HTTP long-polling used by Web applications may not be adequate in long-term communications. To overcome this problem, we include the WebSocket protocol in the design of the CoAP proxy. We evaluate the performance of the CoAP proxy in terms of latency and memory consumption. The tests consider long and short-lived communications. In both cases, we evaluate the performance obtained by the CoAP proxy according to the use of WebSocket and HTTP long-polling. Wireless sensor networks (WSNs) are starting to have a high impact on our societies and, for next generation WSNs to become more integrated with the Internet, researchers recently proposed to embed IPv6 into such very constrained networks. Also, constraint application protocol (CoAP) and Observe have been proposed for RESTful services to be provided. CoAP Observe supports the use of caches proxies and, for this reason, an observation request may resort to multiple client server registration steps in order to get notifications. Here, we propose to plan the multiple registration steps, at proxies, of multiple observation requests in order to make proper aggregation scheduling of notifications for transmission. This leads to less energy consumption and to an effective use of bandwidth, avoiding energy depletion of nodes, and increasing the network lifetime. Besides, mathematically formalizing the problem, a heuristic approach is developed and a discussion on how to incorporate algorithm’s decision into the network is done. The proposed framework can be applied to multiple application domains (e.g., monitoring, machine to machine).