LPWAN Static Context Header Compression (SCHC) for CoAP
draft-ietf-lpwan-coap-static-context-hc-14
| The information below is for an old version of the document | |||
|---|---|---|---|
| Document | Type | Active Internet-Draft (lpwan WG) | |
| Authors | Ana Minaburo , Laurent Toutain , Ricardo Andreasen | ||
| Last updated | 2020-07-02 (latest revision 2020-05-26) | ||
| Replaces | draft-toutain-lpwan-coap-static-context-hc | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | pdf htmlized (tools) htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Pascal Thubert | ||
| Shepherd write-up | Show (last changed 2019-10-09) | ||
| IESG | IESG state | IESG Evaluation::Revised I-D Needed | |
| Consensus Boilerplate | Yes | ||
| Telechat date |
Has enough positions to pass. |
||
| Responsible AD | Éric Vyncke | ||
| Send notices to | Pascal Thubert <pthubert@cisco.com> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
lpwan Working Group A. Minaburo
Internet-Draft Acklio
Intended status: Standards Track L. Toutain
Expires: November 27, 2020 Institut MINES TELECOM; IMT Atlantique
R. Andreasen
Universidad de Buenos Aires
May 26, 2020
LPWAN Static Context Header Compression (SCHC) for CoAP
draft-ietf-lpwan-coap-static-context-hc-14
Abstract
This draft defines the way Static Context Header Compression (SCHC)
header compression can be applied to the Constrained Application
Protocol (CoAP). SCHC is a header compression mechanism adapted for
constrained devices. SCHC uses a static description of the header to
reduce the redundancy and the size of the information in the header.
While [rfc8724] describes the SCHC compression and fragmentation
framework, and its application for IPv6/UDP headers, this document
applies the use of SCHC for CoAP headers. The CoAP header structure
differs from IPv6 and UDP since CoAP uses a flexible header with a
variable number of options, themselves of variable length. The CoAP
protocol messages format is asymmetric: the request messages have a
header format different from the one in the response messages. This
specification gives guidance on how to apply SCHC to flexible headers
and how to leverage the asymmetry for more efficient compression
Rules.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
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 November 27, 2020.
Minaburo, et al. Expires November 27, 2020 [Page 1]
Internet-Draft LPWAN CoAP compression May 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Applying SCHC to CoAP headers . . . . . . . . . . . . . . . . 4
3. CoAP Headers compressed with SCHC . . . . . . . . . . . . . . 5
3.1. Differences between CoAP and UDP/IP Compression . . . . . 5
4. Compression of CoAP header fields . . . . . . . . . . . . . . 6
4.1. CoAP version field . . . . . . . . . . . . . . . . . . . 7
4.2. CoAP type field . . . . . . . . . . . . . . . . . . . . . 7
4.3. CoAP code field . . . . . . . . . . . . . . . . . . . . . 7
4.4. CoAP Message ID field . . . . . . . . . . . . . . . . . . 7
4.5. CoAP Token fields . . . . . . . . . . . . . . . . . . . . 7
5. CoAP options . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. CoAP Content and Accept options. . . . . . . . . . . . . 8
5.2. CoAP option Max-Age, Uri-Host and Uri-Port fields . . . . 8
5.3. CoAP option Uri-Path and Uri-Query fields . . . . . . . . 9
5.3.1. Variable length Uri-Path and Uri-Query . . . . . . . 9
5.3.2. Variable number of path or query elements . . . . . . 10
5.4. CoAP option Size1, Size2, Proxy-URI and Proxy-Scheme
fields . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.5. CoAP option ETag, If-Match, If-None-Match, Location-Path
and Location-Query fields . . . . . . . . . . . . . . . . 10
6. SCHC compression of CoAP extension RFCs . . . . . . . . . . . 11
6.1. Block . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.2. Observe . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.3. No-Response . . . . . . . . . . . . . . . . . . . . . . . 11
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