lpwan Working Group JC. Zuniga
Internet-Draft SIGFOX
Intended status: Informational C. Gomez
Expires: May 3, 2018 Universitat Politecnica de Catalunya
L. Toutain
IMT-Atlantique
October 30, 2017
SCHC over Sigfox LPWAN
draft-zuniga-lpwan-schc-over-sigfox-00
Abstract
The Static Context Header Compression (SCHC) specification describes
a header compression scheme and fragmentation functionality for LPWAN
(Low Power Wide Area Network) technologies. SCHC offers a great
level of flexibility that can be tailored for different LPWAN
technologies.
The present document provides the optimal parameters and modes of
operation when SCHC is implemented over a Sigfox LPWAN.
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 May 3, 2018.
Copyright Notice
Copyright (c) 2017 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
Zuniga, et al. Expires May 3, 2018 [Page 1]
Internet-Draft SCHC over Sigfox LPWAN October 2017
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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Static Context Header Compression . . . . . . . . . . . . . . 3
3.1. SCHC Rules . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Packet processing . . . . . . . . . . . . . . . . . . . . 4
4. Fragmentation . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Fragmantation headers . . . . . . . . . . . . . . . . . . 4
4.2. Uplink fragment transmission . . . . . . . . . . . . . . 4
4.3. Downlink fragment transmission . . . . . . . . . . . . . 4
5. Security considerations . . . . . . . . . . . . . . . . . . . 5
6. Informative References . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
The Static Context Header Compression (SCHC) specification
[I-D.ietf-lpwan-ipv6-static-context-hc] defines a header compression
scheme and fragmentation functionality that can be used on top of all
the LWPAN systems defined in [I-D.ietf-lpwan-overview]. These LPWAN
systems have similar characteristics such as star-oriented
topologies, network architecture, connected devices with built-in
applications, etc.
SCHC offers a great level of flexibility to accomodate all these
LPWAN systems. Even though there are a great number of similarities
between LPWAN technologies, some slight differences exist with
respect to the tranmission characteristics, payload sizes, etc.
Hence, there are optimal parameters and modes of operation that can
be used when SCHC is used on top of a specific LPWAN.
This document describes the optimal parameters and modes of operation
when SCHC is implemented over a Sigfox LPWAN.
2. Terminology
The reader is assumed to be familiar with the terms and mechanisms
defined in [I-D.ietf-lpwan-overview] and in
[I-D.ietf-lpwan-ipv6-static-context-hc].
Zuniga, et al. Expires May 3, 2018 [Page 2]
Internet-Draft SCHC over Sigfox LPWAN October 2017
3. Static Context Header Compression
Static Context Header Compression (SCHC) avoids context
synchronization because data flows are highly predictable in LPWAN
networks. Contexts must be stored in both ends, and they can be
learned by a provisioning protocol, by out of band means, or they can
be pre-provisioned. The way the context is learned on both sides is
out of the scope of this document.
Dev App
+--------------+ +--------------+
|APP1 APP2 APP3| |APP1 APP2 APP3|
| | | |
| UDP | | UDP |
| IPv6 | | IPv6 |
| | | |
| SCHC C/D | | |
| (context) | | |
+-------+------+ +-------+------+
| +--+ +----+ +---------+ .
+~~ |RG| === |NGW | === |SCHC C/D |... Internet ..
+--+ +----+ |(context)|
+---------+
Figure 1: Architecture
Figure 1 represents the architecture for compression/decompression
and fragmentation, which is based on [I-D.ietf-lpwan-overview]
terminology.
The Device is sending applications flows that are compressed (and/or
fragmented) by a Static Context Header Compression Compressor/
Decompressor (SCHC C/D) to reduce headers size and/or fragment the
packet. The resulting information is sent to a layer two (L2) frame
to a LPWAN Radio Network (RG) which forwards the frame to a Network
Gateway (NGW).
The NGW sends the data to an SCHC C/D for decompression (and/or
reassembly) which shares the same rules with the Dev. The SCHC C/D
can be located on the Network Gateway (NGW) or in another place as
long as a tunnel is established between the NGW and the SCHC C/D.
The SCHC C/D in both sides must share the same set of Rules. After
decompression (and/or reassembly), the packet can be forwarded to one
or several LPWAN Application Servers (App).
The SCHC C/D process is bidirectional, so the same principles can be
applied in both uplink and downlink.
Zuniga, et al. Expires May 3, 2018 [Page 3]
Internet-Draft SCHC over Sigfox LPWAN October 2017
3.1. SCHC Rules
TBD
3.2. Packet processing
TBD
4. Fragmentation
The SCHC specification [I-D.ietf-lpwan-ipv6-static-context-hc]
supports several modes of operation to fragment packets. These modes
have different advantages and disadvantages depending on the specific
of the underlying LPWAN technology. This section describes how the
SCHC fragmentation functionality SHOULD optimally be used over a
Sigfox LPWAN.
4.1. Fragmantation headers
A list of fragmentation header fields, their sizes and related
details for SCHC fragmentation over Sigfox are provided below:
TBD
4.2. Uplink fragment transmission
TBD
4.3. Downlink fragment transmission
In some LPWAN technologies, as part of energy-saving techniques,
downlink transmission is only possible immediately after an uplink
transmission. This allows the device to go in a very deep sleep mode
and preserve battery, without the need to listen to any information
from the network. This is the case for Sigfox devices, which can
only listen to downlink communications after performing an uplink
transmission.
When there are multiple fragments to be transmitted in the downlink,
an uplink message is required to trigger the downlink communication.
In order to avoid potentially high delay for fragmented datagram
transmission in the downlink, the fragment receiver MAY perform an
uplink transmission as soon as possible after reception of a fragment
that is not the last one. Such uplink transmission may be triggered
by sending a SCHC message, such as an ACK.
Zuniga, et al. Expires May 3, 2018 [Page 4]
Internet-Draft SCHC over Sigfox LPWAN October 2017
5. Security considerations
TBD
6. Informative References
[I-D.ietf-lpwan-ipv6-static-context-hc]
Minaburo, A., Toutain, L., and C. Gomez, "LPWAN Static
Context Header Compression (SCHC) and fragmentation for
IPv6 and UDP", draft-ietf-lpwan-ipv6-static-context-hc-07
(work in progress), October 2017.
[I-D.ietf-lpwan-overview]
Farrell, S., "LPWAN Overview", draft-ietf-lpwan-
overview-07 (work in progress), October 2017.
Authors' Addresses
Juan Carlos Zuniga
SIGFOX
425 rue Jean Rostand
Labege 31670
France
Email: JuanCarlos.Zuniga@sigfox.com
URI: http://www.sigfox.com/
Carles Gomez
Universitat Politecnica de Catalunya
C/Esteve Terradas, 7
08860 Castelldefels
Spain
Email: carlesgo@entel.upc.edu
Laurent Toutain
IMT-Atlantique
2 rue de la Chataigneraie
CS 17607
35576 Cesson-Sevigne Cedex
France
Email: Laurent.Toutain@imt-atlantique.fr
Zuniga, et al. Expires May 3, 2018 [Page 5]