@techreport{ma-core-stateful-observe-02,
    number =    {draft-ma-core-stateful-observe-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ma-core-stateful-observe/02/},
    author =    {Changsha Ma and Peilin Hong and Kaiping Xue},
    title =     {{Stateful Observation in CoAP}},
    pagetotal = 16,
    year =      2013,
    month =     jun,
    day =       24,
    abstract =  {The Observe Option allows a CoAP client to observe changes in the state of resources and obtain a current representation of the last resource state. To be an observer of an origin server's resources, the client is required to register its interest with the server. A successful registration will make the client added into the server's observation list, while a failed one MAY drive the client to re- register. However, repeated and frequent re-registrations cannot guarantee the client to eventually become an observer of the target server. In the case that the server is unable or unwilling to accept an observer, the time-intensive re-registrations will just bring redundant messages in the constrained network and considerable energy consumption on both the client and the server. This memo defines a new CoAP option, State, for providing stateful observation on the resources of CoAP servers. By observing the state of the server in terms of the Observe Option, a client can explicitly learn when the server will not actively reject an observation registration, and then can wisely performs the re-registration. This avoids the potential registration flooding that causes considerable network overhead and energy consumption on the constrained nodes.},
}