Observing Resources in the Constrained Application Protocol (CoAP)
RFC 7641
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RFC - Proposed Standard
(September 2015; No errata)
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Last updated |
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2015-10-14
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Replaces |
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draft-hartke-coap-observe
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IETF
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plain text
pdf
html
bibtex
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Reviews |
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Carsten Bormann
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Shepherd write-up |
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Show
(last changed 2014-07-20)
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| IESG |
IESG state |
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RFC 7641 (Proposed Standard)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Barry Leiba
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Send notices to |
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(None)
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| IANA |
IANA review state |
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Version Changed - Review Needed
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IANA action state |
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RFC-Ed-Ack
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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 Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7641.
Hartke Standards Track [Page 1]
RFC 7641 Observing Resources in CoAP September 2015
Copyright Notice
Copyright (c) 2015 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
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.
Hartke Standards Track [Page 2]
RFC 7641 Observing Resources in CoAP September 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Protocol Overview . . . . . . . . . . . . . . . . . . . . 4
1.3. Consistency Model . . . . . . . . . . . . . . . . . . . . 6
1.4. Observable Resources . . . . . . . . . . . . . . . . . . 7
1.5. Requirements Notation . . . . . . . . . . . . . . . . . . 8
2. The Observe Option . . . . . . . . . . . . . . . . . . . . . 9
3. Client-Side Requirements . . . . . . . . . . . . . . . . . . 10
3.1. Request . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2. Notifications . . . . . . . . . . . . . . . . . . . . . . 10
3.3. Caching . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.4. Reordering . . . . . . . . . . . . . . . . . . . . . . . 12
3.5. Transmission . . . . . . . . . . . . . . . . . . . . . . 13
3.6. Cancellation . . . . . . . . . . . . . . . . . . . . . . 13
4. Server-Side Requirements . . . . . . . . . . . . . . . . . . 14
4.1. Request . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Notifications . . . . . . . . . . . . . . . . . . . . . . 14
4.3. Caching . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4. Reordering . . . . . . . . . . . . . . . . . . . . . . . 16
4.5. Transmission . . . . . . . . . . . . . . . . . . . . . . 17
5. Intermediaries . . . . . . . . . . . . . . . . . . . . . . . 20
6. Web Linking . . . . . . . . . . . . . . . . . . . . . . . . . 20
7. Security Considerations . . . . . . . . . . . . . . . . . . . 21
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1. Normative References . . . . . . . . . . . . . . . . . . 22
9.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 24
A.1. Client/Server Examples . . . . . . . . . . . . . . . . . 24
A.2. Proxy Examples . . . . . . . . . . . . . . . . . . . . . 28
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 30
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