Fragmentation in LPWAN considerations: CoAP Block vs SCHC fragmentation
draft-gomez-frag-lpwan-considerations-00

Document Type Active Internet-Draft (individual)
Last updated 2019-08-27
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
LPWAN Working Group                                             C. Gomez
Internet-Draft                                                       UPC
Intended status: Informational                              J. Crowcroft
Expires: February 27, 2020                       University of Cambridge
                                                         August 26, 2019

Fragmentation in LPWAN considerations: CoAP Block vs SCHC fragmentation
                draft-gomez-frag-lpwan-considerations-00

Abstract

   The SCHC adaptation layer provides header compression and
   fragmentation functionality between IPv6 and an underlying LPWAN
   technology.  SCHC fragmentation has been specifically designed for
   the characteristics of LPWANs.  However, when CoAP is used at the
   application layer, there exists an alternative approach for
   fragmentation, which is using the CoAP Block option.  This document
   aims at illustrating the advantages and limitations of each approach
   for transferring larger payloads.

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 February 27, 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 and restrictions with respect

Gomez & Crowcroft       Expires February 27, 2020               [Page 1]
Internet-Draft          LPWAN frag considerations            August 2019

   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
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Header overhead . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  L2 MTU supported  . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Reliability modes . . . . . . . . . . . . . . . . . . . . . .   4
   6.  CoAP RTO calculation  . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The Static Context Header Compression and fragmentation (SCHC)
   framework provides an adaptation layer that has been specifically
   designed to enable support of IPv6 over Low Power Wide Area Network
   (LPWAN) technologies [I-D.ietf-lpwan-ipv6-static-context-hc].  SCHC
   comprises header compression and fragmentation functionality.  The
   latter is needed when SCHC is used over technologies such as LoRaWAN
   or Sigfox [RFC8376], and might be needed over further LPWAN
   technologies.

   On the other hand, considering the significant resource constraints
   in many LPWAN scenarios, the Constrained Application Protocol (CoAP)
   is a suitable candidate application-layer protocol for use in LPWAN.
   CoAP has been specified over both UDP and TCP [RFC7252][RFC8323].
   For CoAP over UDP, the Block option can be used in order to perform
   application-layer fragmentation [RFC7959].  In this document, CoAP
   over UDP is assumed.

   Therefore, when CoAP and SCHC are used in LPWAN, there exist two
   possible approaches for fragmentation: SCHC-level fragmentation and
   CoAP-level fragmentation.  This document aims at systematically
   analyzing the characteristics, advantages and limitations of both
   approaches.

Gomez & Crowcroft       Expires February 27, 2020               [Page 2]
Internet-Draft          LPWAN frag considerations            August 2019

2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL","SHALL NOT",
Show full document text