6LoWPAN Selective Fragment Recovery
draft-thubert-6lo-fragment-recovery-00

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6lo                                                      P. Thubert, Ed.
Internet-Draft                                             Cisco Systems
Updates: 4944 (if approved)                            February 21, 2018
Intended status: Standards Track
Expires: August 25, 2018

                  6LoWPAN Selective Fragment Recovery
                 draft-thubert-6lo-fragment-recovery-00

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.

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   This Internet-Draft will expire on August 25, 2018.

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   Copyright (c) 2018 IETF Trust and the persons identified as the
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Thubert                  Expires August 25, 2018                [Page 1]
Internet-Draft     6LoWPAN Selective Fragment Recovery          February

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Updating RFC 4944 . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Updating draft-watteyne-6lo-minimal-fragment  . . . . . . . .   4
   4.  Terminology and Referenced Work . . . . . . . . . . . . . . .   4
   5.  New Dispatch types and headers  . . . . . . . . . . . . . . .   5
     5.1.  Recoverable Fragment Dispatch type and Header . . . . . .   6
     5.2.  RFRAG Acknowledgment Dispatch type and Header . . . . . .   8
   6.  Fragments Recovery  . . . . . . . . . . . . . . . . . . . . .   9
   7.  Forwarding Fragments  . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Upon the first fragment . . . . . . . . . . . . . . . . .  11
     7.2.  Upon the next fragments . . . . . . . . . . . . . . . . .  12
     7.3.  Upon the RFRAG Acknowledgments  . . . . . . . . . . . . .  12
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  13
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     11.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Appendix A.  Rationale  . . . . . . . . . . . . . . . . . . . . .  15
   Appendix B.  Requirements . . . . . . . . . . . . . . . . . . . .  17
   Appendix C.  Considerations On Flow Control . . . . . . . . . . .  18
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  19

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 74 bytes or more in all cases,
   fragmentation is usually not required.  However, and though this
   happens only occasionally, a number of mission critical applications
   do require the capability to transfer larger chunks of data, for
   instance to support a firmware upgrades of the LLN nodes or an
   extraction of logs from LLN nodes.  In the former case, the large
   chunk of data is transferred to the LLN node, whereas in the latter,
   the large chunk flows away from the LLN node.  In both cases, the
   size can be on the order of 10Kbytes or more and an end-to-end
   reliable transport is required.

   "Transmission of IPv6 Packets over IEEE 802.15.4 Networks" [RFC4944]
   defines the original 6LoWPAN datagram fragmentation mechanism for
   LLNs.  One critical issue with this original design is that routing
   an IPv6 [RFC8200] packet across a route-over mesh requires to
   reassemble the full packet at each hop, which may cause latency along