SCHC: Generic Framework for Static Context Header Compression and Fragmentation
RFC 8724

Document Type RFC - Proposed Standard (April 2020; No errata)
Authors Ana Minaburo  , Laurent Toutain  , Carles Gomez  , Dominique Barthel  , Juan-Carlos Zúñiga 
Last updated 2020-04-15
Replaces draft-toutain-lpwan-ipv6-static-context-hc
Stream Internet Engineering Task Force (IETF)
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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 8724 (Proposed Standard)
Action Holders
Consensus Boilerplate Yes
Telechat date
Responsible AD Suresh Krishnan
Send notices to Dominique Barthel <>, Pascal Thubert <>
IANA IANA review state Version Changed - Review Needed
IANA action state No IANA Actions

Internet Engineering Task Force (IETF)                       A. Minaburo
Request for Comments: 8724                                        Acklio
Category: Standards Track                                     L. Toutain
ISSN: 2070-1721                                           IMT Atlantique
                                                                C. Gomez
                                    Universitat Politecnica de Catalunya
                                                              D. Barthel
                                                             Orange Labs
                                                              JC. Zuniga
                                                              April 2020

   SCHC: Generic Framework for Static Context Header Compression and


   This document defines the Static Context Header Compression and
   fragmentation (SCHC) framework, which provides both a header
   compression mechanism and an optional fragmentation mechanism.  SCHC
   has been designed with Low-Power Wide Area Networks (LPWANs) in mind.

   SCHC compression is based on a common static context stored both in
   the LPWAN device and in the network infrastructure side.  This
   document defines a generic header compression mechanism and its
   application to compress IPv6/UDP headers.

   This document also specifies an optional fragmentation and reassembly
   mechanism.  It can be used to support the IPv6 MTU requirement over
   the LPWAN technologies.  Fragmentation is needed for IPv6 datagrams
   that, after SCHC compression or when such compression was not
   possible, still exceed the Layer 2 maximum payload size.

   The SCHC header compression and fragmentation mechanisms are
   independent of the specific LPWAN technology over which they are
   used.  This document defines generic functionalities and offers
   flexibility with regard to parameter settings and mechanism choices.
   This document standardizes the exchange over the LPWAN between two
   SCHC entities.  Settings and choices specific to a technology or a
   product are expected to be grouped into profiles, which are specified
   in other documents.  Data models for the context and profiles are out
   of scope.

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 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

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
   ( 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
   2.  Requirements Notation
   3.  LPWAN Architecture
   4.  Terminology
   5.  SCHC Overview
     5.1.  SCHC Packet Format
     5.2.  Functional Mapping
   6.  RuleID
   7.  Compression/Decompression
     7.1.  SCHC C/D Rules
     7.2.  Packet Processing
     7.3.  Matching Operators
     7.4.  Compression/Decompression Actions (CDA)
       7.4.1.  Processing Fixed-Length Fields
       7.4.2.  Processing Variable-Length Fields
       7.4.3.  Not-Sent CDA
       7.4.4.  Value-Sent CDA
       7.4.5.  Mapping-Sent CDA
       7.4.6.  LSB CDA
       7.4.7.  DevIID, AppIID CDA
       7.4.8.  Compute-*
   8.  Fragmentation/Reassembly
     8.1.  Overview
     8.2.  SCHC F/R Protocol Elements
       8.2.1.  Messages
       8.2.2.  Tiles, Windows, Bitmaps, Timers, Counters
       8.2.3.  Integrity Checking
       8.2.4.  Header Fields
     8.3.  SCHC F/R Message Formats
       8.3.1.  SCHC Fragment Format
       8.3.2.  SCHC ACK Format
       8.3.3.  SCHC ACK REQ Format
       8.3.4.  SCHC Sender-Abort Format
       8.3.5.  SCHC Receiver-Abort Format
     8.4.  SCHC F/R Modes
       8.4.1.  No-ACK Mode
       8.4.2.  ACK-Always Mode
       8.4.3.  ACK-on-Error Mode
   9.  Padding Management
   10. SCHC Compression for IPv6 and UDP Headers
     10.1.  IPv6 Version Field
     10.2.  IPv6 Traffic Class Field
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