LPWAN Static Context Header Compression (SCHC) for CoAP
draft-ietf-lpwan-coap-static-context-hc-19

Document Type Active Internet-Draft (lpwan WG)
Authors Ana Minaburo  , Laurent Toutain  , Ricardo Andreasen 
Last updated 2021-04-07 (latest revision 2021-03-08)
Replaces draft-toutain-lpwan-coap-static-context-hc
Stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Formats plain text xml 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 RFC Ed Queue
Action Holders
(None)
Consensus Boilerplate Yes
Telechat date
Responsible AD √Čric Vyncke
Send notices to Pascal Thubert <pthubert@cisco.com>
IANA IANA review state Version Changed - Review Needed
IANA action state No IANA Actions
RFC Editor RFC Editor state AUTH
Details
lpwan Working Group                                          A. Minaburo
Internet-Draft                                                    Acklio
Intended status: Standards Track                              L. Toutain
Expires: September 9, 2021        Institut MINES TELECOM; IMT Atlantique
                                                            R. Andreasen
                                             Universidad de Buenos Aires
                                                          March 08, 2021

        LPWAN Static Context Header Compression (SCHC) for CoAP
               draft-ietf-lpwan-coap-static-context-hc-19

Abstract

   This draft defines how to compress the Constrained Application
   Protocol (CoAP) using the Static Context Header Compression (SCHC).
   SCHC is a header compression mechanism adapted for Constrained
   Devices.  SCHC uses a static description of the header to reduce the
   header's redundancy and size.  While RFC 8724 describes the SCHC
   compression and fragmentation framework, and its application for
   IPv6/UDP headers, this document applies 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 applying
   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-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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 September 9, 2021.

Minaburo, et al.        Expires September 9, 2021               [Page 1]
Internet-Draft           LPWAN CoAP compression               March 2021

Copyright Notice

   Copyright (c) 2021 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
   (https://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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  SCHC Applicability to CoAP  . . . . . . . . . . . . . . . . .   4
   3.  CoAP Headers compressed with SCHC . . . . . . . . . . . . . .   7
     3.1.  Differences between CoAP and UDP/IP Compression . . . . .   8
   4.  Compression of CoAP header fields . . . . . . . . . . . . . .   9
     4.1.  CoAP version field  . . . . . . . . . . . . . . . . . . .   9
     4.2.  CoAP type field . . . . . . . . . . . . . . . . . . . . .   9
     4.3.  CoAP code field . . . . . . . . . . . . . . . . . . . . .   9
     4.4.  CoAP Message ID field . . . . . . . . . . . . . . . . . .  10
     4.5.  CoAP Token fields . . . . . . . . . . . . . . . . . . . .  10
   5.  CoAP options  . . . . . . . . . . . . . . . . . . . . . . . .  10
     5.1.  CoAP Content and Accept options.  . . . . . . . . . . . .  11
     5.2.  CoAP option Max-Age, Uri-Host, and Uri-Port fields  . . .  11
     5.3.  CoAP option Uri-Path and Uri-Query fields . . . . . . . .  11
       5.3.1.  Variable number of Path or Query elements . . . . . .  13
     5.4.  CoAP option Size1, Size2, Proxy-URI and Proxy-Scheme
           fields  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     5.5.  CoAP option ETag, If-Match, If-None-Match, Location-Path,
           and Location-Query fields . . . . . . . . . . . . . . . .  13
   6.  SCHC compression of CoAP extension RFCs . . . . . . . . . . .  13
     6.1.  Block . . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.2.  Observe . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.3.  No-Response . . . . . . . . . . . . . . . . . . . . . . .  14
     6.4.  OSCORE  . . . . . . . . . . . . . . . . . . . . . . . . .  14
   7.  Examples of CoAP header compression . . . . . . . . . . . . .  15
Show full document text