6LoWPAN Selective Fragment Recovery
draft-ietf-6lo-fragment-recovery-08

Document Type Active Internet-Draft (6lo WG)
Last updated 2019-11-28
Replaces draft-thubert-6lo-fragment-recovery
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication
Document shepherd Carles Gomez
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6lo                                                      P. Thubert, Ed.
Internet-Draft                                             Cisco Systems
Updates: 4944 (if approved)                             28 November 2019
Intended status: Standards Track                                        
Expires: 31 May 2020

                  6LoWPAN Selective Fragment Recovery
                  draft-ietf-6lo-fragment-recovery-08

Abstract

   This draft updates RFC 4944 with a simple protocol to recover
   individual fragments across a route-over mesh network, with a minimal
   flow control to protect the network against bloat.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 31 May 2020.

Copyright Notice

   Copyright (c) 2019 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
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   provided without warranty as described in the Simplified BSD License.

Thubert                    Expires 31 May 2020                  [Page 1]
Internet-Draft               Selective RFRAG               November 2019

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  BCP 14  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  References  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  New Terms . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Updating RFC 4944 . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Extending draft-ietf-6lo-minimal-fragment . . . . . . . . . .   6
     4.1.  Slack in the First Fragment . . . . . . . . . . . . . . .   7
     4.2.  Gap between frames  . . . . . . . . . . . . . . . . . . .   7
     4.3.  Modifying the First Fragment  . . . . . . . . . . . . . .   7
   5.  New Dispatch types and headers  . . . . . . . . . . . . . . .   8
     5.1.  Recoverable Fragment Dispatch type and Header . . . . . .   8
     5.2.  RFRAG Acknowledgment Dispatch type and Header . . . . . .  11
   6.  Fragments Recovery  . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  Forwarding Fragments  . . . . . . . . . . . . . . . . . .  14
       6.1.1.  Upon the first fragment . . . . . . . . . . . . . . .  14
       6.1.2.  Upon the next fragments . . . . . . . . . . . . . . .  15
     6.2.  Upon the RFRAG Acknowledgments  . . . . . . . . . . . . .  16
     6.3.  Aborting the Transmission of a Fragmented Packet  . . . .  16
     6.4.  Applying Recoverable Fragmentation along a Diverse
           Path  . . . . . . . . . . . . . . . . . . . . . . . . . .  17
   7.  Management Considerations . . . . . . . . . . . . . . . . . .  17
     7.1.  Protocol Parameters . . . . . . . . . . . . . . . . . . .  17
     7.2.  Observing the network . . . . . . . . . . . . . . . . . .  19
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  20
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  20
   12. Informative References  . . . . . . . . . . . . . . . . . . .  21
   Appendix A.  Rationale  . . . . . . . . . . . . . . . . . . . . .  24
   Appendix B.  Requirements . . . . . . . . . . . . . . . . . . . .  25
   Appendix C.  Considerations On Flow Control . . . . . . . . . . .  26
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  27

1.  Introduction

   In most Low Power and Lossy Network (LLN) applications, the bulk of
   the traffic consists of small chunks of data (in the order few bytes
   to a few tens of bytes) at a time.  Given that an IEEE Std. 802.15.4
   [IEEE.802.15.4] frame can carry a payload of 74 bytes or more,
   fragmentation is usually not required.  However, and though this
   happens only occasionally, a number of mission critical applications
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