LPWAN Static Context Header Compression (SCHC) for CoAP
draft-ietf-lpwan-coap-static-context-hc-15

Document Type Active Internet-Draft (lpwan WG)
Last updated 2020-07-06 (latest revision 2020-07-03)
Replaces draft-toutain-lpwan-coap-static-context-hc
Stream 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 IESG Evaluation
Consensus Boilerplate Yes
Telechat date On agenda of 2020-07-16 IESG telechat (returning item)
Has 2 DISCUSSes. Needs 2 more YES or NO OBJECTION positions to pass.
Responsible AD √Čric 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: January 4, 2021          Institut MINES TELECOM; IMT Atlantique
                                                            R. Andreasen
                                             Universidad de Buenos Aires
                                                           July 03, 2020

        LPWAN Static Context Header Compression (SCHC) for CoAP
               draft-ietf-lpwan-coap-static-context-hc-15

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-
   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 January 4, 2021.

Minaburo, et al.         Expires January 4, 2021                [Page 1]
Internet-Draft           LPWAN CoAP compression                July 2020

Copyright Notice

   Copyright (c) 2020 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.  Applying SCHC to CoAP headers . . . . . . . . . . . . . . . .   4
   3.  CoAP Headers compressed with SCHC . . . . . . . . . . . . . .   6
     3.1.  Differences between CoAP and UDP/IP Compression . . . . .   7
   4.  Compression of CoAP header fields . . . . . . . . . . . . . .   8
     4.1.  CoAP version field  . . . . . . . . . . . . . . . . . . .   8
     4.2.  CoAP type field . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  CoAP code field . . . . . . . . . . . . . . . . . . . . .   8
     4.4.  CoAP Message ID field . . . . . . . . . . . . . . . . . .   9
     4.5.  CoAP Token fields . . . . . . . . . . . . . . . . . . . .   9
   5.  CoAP options  . . . . . . . . . . . . . . . . . . . . . . . .   9
     5.1.  CoAP Content and Accept options.  . . . . . . . . . . . .  10
     5.2.  CoAP option Max-Age, Uri-Host and Uri-Port fields . . . .  10
     5.3.  CoAP option Uri-Path and Uri-Query fields . . . . . . . .  10
       5.3.1.  Variable length Uri-Path and Uri-Query  . . . . . . .  11
       5.3.2.  Variable number of path or query elements . . . . . .  11
     5.4.  CoAP option Size1, Size2, Proxy-URI and Proxy-Scheme
           fields  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.5.  CoAP option ETag, If-Match, If-None-Match, Location-Path
           and Location-Query fields . . . . . . . . . . . . . . . .  12
   6.  SCHC compression of CoAP extension RFCs . . . . . . . . . . .  12
     6.1.  Block . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     6.2.  Observe . . . . . . . . . . . . . . . . . . . . . . . . .  12
     6.3.  No-Response . . . . . . . . . . . . . . . . . . . . . . .  12
Show full document text