Constrained Application Protocol: Difference between revisions

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'''Constrained Application Protocol''' ('''CoAP''') is a specialized Internet Applicationapplication Protocolprotocol for constrained devices, as defined in <nowiki>RFC 7252</nowiki>. It enables those constrained devices called "nodes" to communicate with the wider Internet using similar protocols.

CoAP is designed for use between devices on the same constrained network (e.g., low-power, lossy networks), between devices and general nodes on the Internet, and between devices on different constrained networks both joined by an internet. CoAP is also being used via other mechanisms, such as SMS on mobile communication networks.

CoAP is a [[service layer]] protocol that is intended for use in resource-constrained internet devices, such as [[wireless sensor network]] nodes. CoAP is designed to easily translate to [[HTTP]] for simplified integration with the web, while also meeting specialized requirements such as [[multicast]] support, very low overhead, and simplicity.<ref>[https://tools.ietf.org/html/rfc7252 RFC 7252, Constrained Application Protocol (CoAP)]</ref><ref>"[http://hinrg.cs.jhu.edu/joomla/images/stories/IPSN_2011_koliti.pdf Integrating Wireless Sensor Networks with the Web]" , Walter, Colitti 2011</ref> Multicast, low overhead, and simplicity are extremely important for [[Internet of Thingsthings]] (IoT) and [[Machinemachine-to-Machinemachine]] (M2M) devicescommunication, which tend to be deeply [[Embedded system|embedded]] and have much less memory and power supply than traditional internet devices have. Therefore, efficiency is very important. CoAP can run on most devices that support [[User Datagram Protocol|UDP]] or a UDP analogue.

The Internet Engineering Task Force ([[IETF]]) Constrained [[RESTful]] Environments Working Group ([https://datatracker.ietf.org/doc/charter-ietf-core/ CoRE]) has done the major standardization work for this protocol. In order to make the protocol suitable to IoT and M2M applications, various new functions have been added.