lpwan Working Group N. Sornin, Ed.
Internet-Draft M. Coracin
Intended status: Informational Semtech
Expires: September 6, 2018 I. Petrov
Acklio
A. Yegin
Actility
J. Catalano
Kerlink
V. Audebert
EDF R&D
March 05, 2018
Static Context Header Compression (SCHC) over LoRaWAN
draft-petrov-lpwan-ipv6-schc-over-lorawan-01
Abstract
The Static Context Header Compression (SCHC) specification describes
generic header compression and fragmentation techniques for LPWAN
(Low Power Wide Area Networks) technologies. SCHC is a generic
mechanism designed for great flexibility, so that it can be adapted
for any of the LPWAN technologies.
This document provides the adaptation of SCHC for use in LoRaWAN
networks, and provides elements such as efficient parameterization
and modes of operation.
Status of This Memo
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This Internet-Draft will expire on September 6, 2018.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Static Context Header Compression Overview . . . . . . . . . 3
4. LoRaWAN Architecture . . . . . . . . . . . . . . . . . . . . 4
4.1. Device classes (A, B, C) and interactions . . . . . . . . 5
4.2. Device addressing . . . . . . . . . . . . . . . . . . . . 5
4.3. General Message Types . . . . . . . . . . . . . . . . . . 6
4.4. LoRaWAN MAC Frames . . . . . . . . . . . . . . . . . . . 6
5. SCHC over LoRaWAN . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Rule ID management . . . . . . . . . . . . . . . . . . . 6
5.2. IID computation . . . . . . . . . . . . . . . . . . . . . 6
5.3. Fragmentation . . . . . . . . . . . . . . . . . . . . . . 6
5.3.1. Reliability options . . . . . . . . . . . . . . . . . 6
5.3.2. Supporting multiple window sizes . . . . . . . . . . 6
5.3.3. Downlink fragment transmission . . . . . . . . . . . 6
5.3.4. SCHC behavior for devices in class A, B and C . . . . 6
6. Security considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 7
Appendix B. Note . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The Static Context Header Compression (SCHC) specification
[I-D.ietf-lpwan-ipv6-static-context-hc] describes generic header
compression and fragmentation techniques that can be used on all
LPWAN (Low Power Wide Area Networks) technologies defined in
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[I-D.ietf-lpwan-overview]. Even though those technologies share a
great number of common features like start-oriented topologies,
network architecture, devices with mostly quite predictable
communications, etc; they do have some slight differences in respect
of payload sizes, reactiveness, etc.
SCHC gives a generic framework that enables those devices to
communicate with other Internet networks. However, for efficient
performance, some parameters and modes of operation need to be set
appropriately for each of the LPWAN technologies.
This document describes the efficient parameters and modes of
operation when SCHC is used over LoRaWAN networks.
2. Terminology
This section defines the terminology and acronyms used in this
document. For all other definitions, please look up the SCHC
specification [I-D.ietf-lpwan-ipv6-static-context-hc].
o DevEUI: an IEEE EUI-64 identifier used to identify the device
during the procedure while joining the network (Join Procedure)
o DevAddr: a 32-bit non-unique identifier assigned to a device
statically or dynamically after a Join Procedure (depending on the
activation mode)
o TBD: all significant LoRaWAN-related terms.
3. Static Context Header Compression Overview
This section contains a short overview of Static Context Header
Compression (SCHC). For a detailed description, refer to the full
specification [I-D.ietf-lpwan-ipv6-static-context-hc].
Static Context Header Compression (SCHC) avoids context
synchronization, which is the most bandwidth-consuming operation in
other header compression mechanisms such as RoHC [RFC5795]. Based on
the fact that the nature of data flows is highly predictable in LPWAN
networks, some static contexts may be stored on the Device (Dev).
The contexts must be stored in both ends, and it can either be
learned by a provisioning protocol or by out of band means or it can
be pre-provisioned, etc. The way the context is learned on both
sides is out of the scope of this document.
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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,
it is based on [I-D.ietf-lpwan-overview] terminology. The Device is
sending applications flows using IPv6 or IPv6/UDP protocols. These
flows are compressed by an Static Context Header Compression
Compressor/Decompressor (SCHC C/D) to reduce headers size. Resulting
information is sent on 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 a SCHC C/D for decompression 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, the
packet can be sent on the Internet to one or several LPWAN
Application Servers (App).
The SCHC C/D process is bidirectional, so the same principles can be
applied in the other direction.
In a LoRaWAN network, the RG is called a Gateway, the NGW is Network
Server, and the SCHC C/D can be embedded in different places, for
example in the Network Server and/or the Application Server.
Next steps for this section: detailed overview of the LoRaWAN
architecture and its mapping to the SCHC architecture.
4. LoRaWAN Architecture
An overview of LoRaWAN [lora-alliance-spec] protocol and architecture
is described in [I-D.ietf-lpwan-overview]. Mapping between the LPWAN
architecture entities as described in
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[I-D.ietf-lpwan-ipv6-static-context-hc] and the ones in
[lora-alliance-spec] is as follows:
o Devices (Dev) are the end-devices or hosts (e.g. sensors,
actuators, etc.). There can be a very high density of devices per
radio gateway. This entity maps to the LoRaWAN End-device.
o The Radio Gateway (RGW), which is the end point of the constrained
link. This entity maps to the LoRaWAN Gateway.
o The Network Gateway (NGW) is the interconnection node between the
Radio Gateway and the Internet. This entity maps to the LoRaWAN
Network Server.
o LPWAN-AAA Server, which controls the user authentication and the
applications. This entity maps to the LoRaWAN Join Server.
o Application Server (App). The same terminology is used in LoRaWAN.
() () () | +------+
() () () () / \ +---------+ | Join | () () () () () () / \======| ^ |===|Server| +-----------+
() () () | | <--|--> | +------+ |Application| () () () () / \==========| v |=============| Server |
() () () / \ +---------+ +-----------+
End-Devices Gateways Network Server
Figure 1: LPWAN/LoRaWAN Architecture
SCHC C/D (Compressor/Decompressor) and SCHC Fragmentation are
performed on the LoRaWAN End-device and the Application Server.
While the point-to-point link between the End-device and the
Application Server constitutes single IP hop, the ultimate end-point
of the IP communication may be an Internet node beyond the
Application Server. In other words, the LoRaWAN Application Server
acts as the first hop IP router for the End-device. Note that the
Application Server and Network Server may be co-located, which
effectively turns the Network/Application Server into the first hop
IP router.
4.1. Device classes (A, B, C) and interactions
TBD
4.2. Device addressing
TBD
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4.3. General Message Types
TBD
4.4. LoRaWAN MAC Frames
TBD
5. SCHC over LoRaWAN
5.1. Rule ID management
Rule ID can be stored and transported in the FPort field of the
LoRaWAN MAC frame.
TBD
5.2. IID computation
TBD
5.3. Fragmentation
TBD
5.3.1. Reliability options
TBD
5.3.2. Supporting multiple window sizes
TBD
5.3.3. Downlink fragment transmission
TBD
5.3.4. SCHC behavior for devices in class A, B and C
TBD
6. Security considerations
TBD
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7. Acknowledgements
TBD
8. References
8.1. Normative References
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/info/rfc4944>.
[RFC5795] Sandlund, K., Pelletier, G., and L-E. Jonsson, "The RObust
Header Compression (ROHC) Framework", RFC 5795,
DOI 10.17487/RFC5795, March 2010,
<https://www.rfc-editor.org/info/rfc5795>.
[RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6
Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136,
February 2014, <https://www.rfc-editor.org/info/rfc7136>.
8.2. 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-10
(work in progress), February 2018.
[I-D.ietf-lpwan-overview]
Farrell, S., "LPWAN Overview", draft-ietf-lpwan-
overview-10 (work in progress), February 2018.
[lora-alliance-spec]
Alliance, L., "LoRaWAN Specification Version V1.0.2",
<http://portal.lora-
alliance.org/DesktopModules/Inventures_Document/
FileDownload.aspx?ContentID=1398>.
Appendix A. Examples
Appendix B. Note
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Authors' Addresses
Nicolas Sornin (editor)
Semtech
14 Chemin des Clos
Meylan
France
Email: nsornin@semtech.com
Michael Coracin
Semtech
14 Chemin des Clos
Meylan
France
Email: mcoracin@semtech.com
Ivaylo Petrov
Acklio
2bis rue de la Chataigneraie
35510 Cesson-Sevigne Cedex
France
Email: ivaylo@ackl.io
Alper Yegin
Actility
.
Paris, Paris
France
Email: alper.yegin@actility.com
Julien Catalano
Kerlink
1 rue Jacqueline Auriol
35235 Thorigne-Fouillard
France
Email: j.catalano@kerlink.fr
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Vincent AUDEBERT
EDF R&D
7 bd Gaspard Monge
91120 PALAISEAU
FRANCE
Email: vincent.audebert@edf.fr
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