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Observing Resources in CoAP
draft-ietf-core-observe-16

Document type: Active Internet-Draft (core WG)
Document stream: IETF
Last updated: 2014-12-30
Intended RFC status: Proposed Standard
Other versions: plain text, xml, pdf, html

IETF State: Submitted to IESG for Publication Oct 2013
Consensus: Yes
Document shepherd: Carsten Bormann
Shepherd Write-Up: Last changed 2014-07-20

IESG State: IESG Evaluation::AD Followup
IANA Action State: None
(Has enough positions to pass.)
Responsible AD: Barry Leiba
Send notices to: core-chairs@ietf.org, draft-ietf-core-observe@ietf.org, core@ietf.org

CoRE Working Group                                             K. Hartke
Internet-Draft                                   Universitaet Bremen TZI
Intended status: Standards Track                       December 30, 2014
Expires: July 3, 2015

                      Observing Resources in CoAP
                       draft-ietf-core-observe-16

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 Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on July 3, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

Hartke                    Expires July 3, 2015                  [Page 1]
Internet-Draft         Observing Resources in CoAP         December 2014

   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Background . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.2.  Protocol Overview  . . . . . . . . . . . . . . . . . . . .  3
     1.3.  Consistency Model  . . . . . . . . . . . . . . . . . . . .  5
     1.4.  Observable Resources . . . . . . . . . . . . . . . . . . .  6
     1.5.  Requirements Notation  . . . . . . . . . . . . . . . . . .  7
   2.  The Observe Option . . . . . . . . . . . . . . . . . . . . . .  7
   3.  Client-side Requirements . . . . . . . . . . . . . . . . . . .  8
     3.1.  Request  . . . . . . . . . . . . . . . . . . . . . . . . .  8
     3.2.  Notifications  . . . . . . . . . . . . . . . . . . . . . .  8
     3.3.  Caching  . . . . . . . . . . . . . . . . . . . . . . . . .  9
     3.4.  Reordering . . . . . . . . . . . . . . . . . . . . . . . . 10
     3.5.  Transmission . . . . . . . . . . . . . . . . . . . . . . . 11
     3.6.  Cancellation . . . . . . . . . . . . . . . . . . . . . . . 11
   4.  Server-side Requirements . . . . . . . . . . . . . . . . . . . 12
     4.1.  Request  . . . . . . . . . . . . . . . . . . . . . . . . . 12
     4.2.  Notifications  . . . . . . . . . . . . . . . . . . . . . . 13
     4.3.  Caching  . . . . . . . . . . . . . . . . . . . . . . . . . 13
     4.4.  Reordering . . . . . . . . . . . . . . . . . . . . . . . . 14
     4.5.  Transmission . . . . . . . . . . . . . . . . . . . . . . . 15
   5.  Intermediaries . . . . . . . . . . . . . . . . . . . . . . . . 18
   6.  Web Linking  . . . . . . . . . . . . . . . . . . . . . . . . . 19
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 19
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 20
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 21
     10.2. Informative References . . . . . . . . . . . . . . . . . . 21
   Appendix A.  Examples  . . . . . . . . . . . . . . . . . . . . . . 22
     A.1.  Client/Server Examples . . . . . . . . . . . . . . . . . . 22
     A.2.  Proxy Examples . . . . . . . . . . . . . . . . . . . . . . 26

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