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Observing Resources in the Constrained Application Protocol (CoAP)

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: RFC Editor <>,
    core mailing list <>,
    core chair <>
Subject: Protocol Action: 'Observing Resources in CoAP' to Proposed Standard (draft-ietf-core-observe-16.txt)

The IESG has approved the following document:
- 'Observing Resources in CoAP'
  (draft-ietf-core-observe-16.txt) as Proposed Standard

This document is the product of the Constrained RESTful Environments
Working Group.

The IESG contact persons are Ben Campbell, Barry Leiba and Alissa Cooper.

A URL of this Internet Draft is:

Ballot Text

Technical Summary

This specification extends the CoAP protocol (RFC 7252) to allow for
CoAP clients to "observe" changing server-side resources, using a
model of eventual consistency (not every intermediate state is
necessarily delivered).  It is intended for standards-track as it is a
widely implemented extension of a standards-track protocol.

Review and Consensus

The specification was developed along with the base CoAP specification
and received significant review by active WG members and implementers.
One remaining smaller issue without an obvious answer, how to actively
cancel an ongoing observation from the client side, remained under
discussion for quite some time before a solution was finally picked at
IETF89 in London.

Several implementations of this final (post-London) version have
completed an interoperability test event with a very good score.
Further implementer feedback also was positive.
Parts of the specification have already been picked up earlier in OMA
LWM2M and are an element of their 1.0 specification.

The specification benefited from the directorate reviews of the base
specification (in particular with respect to congestion control), but
no separate directorate review of this extension has been performed.


Carsten Bormann is the document shepherd.
Barry Leiba is the responsible Area Director.

RFC Editor note

Please make the following change at the end of Section 3.5:
   observers (Section 4.5).

RFC Editor Note