Observe Notifications as CoAP Multicast Responses

Document Type Replaced Internet-Draft (candidate for core WG)
Authors Marco Tiloca  , Rikard Höglund  , Christian Amsüss  , Francesca Palombini 
Last updated 2021-03-12 (latest revision 2021-02-22)
Replaced by draft-ietf-core-observe-multicast-notifications
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
plain text htmlized pdfized bibtex
Stream WG state Call For Adoption By WG Issued
Document shepherd No shepherd assigned
IESG IESG state Replaced by draft-ietf-core-observe-multicast-notifications
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The Constrained Application Protocol (CoAP) allows clients to "observe" resources at a server, and receive notifications as unicast responses upon changes of the resource state. In some use cases, such as based on publish-subscribe, it would be convenient for the server to send a single notification addressed to all the clients observing a same target resource. This document updates RFC7252 and RFC7641, and defines how a server sends observe notifications as response messages over multicast, synchronizing all the observers of a same resource on a same shared Token value. Besides, this document defines how Group OSCORE can be used to protect multicast notifications end-to-end between the server and the observer clients.


Marco Tiloca (marco.tiloca@ri.se)
Rikard Höglund (rikard.hoglund@ri.se)
Christian Amsüss (christian@amsuess.com)
Francesca Palombini (francesca.palombini@ericsson.com)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)