Internet Engineering Task Force (IETF) K. Hartke Request for Comments: 7641 Universitaet Bremen TZI Category: Standards Track September 2015 ISSN: 2070-1721 Observing Resources in the Constrained Application Protocol (CoAP) Abstract The Constrained Application Protocol (CoAP) is a RESTful application protocol for constrained nodes and networks. The state of a resource on a CoAP server can change over time. This document specifies a simple protocol extension for CoAP that enables CoAP clients to "observe" resources, i.e., to retrieve a representation of a resource and keep this representation updated by the server over a period of time. The protocol follows a best-effort approach for sending new representations to clients and provides eventual consistency between the state observed by each client and the actual resource state at the server. Status of This Mem
