1.
M2M,IoT, device management:
one protocol to rule them all?
Julien Vermillard - Sierra Wireless

2.
Who am I?
Software Engineer at Sierra Wireless,
implementing various protocols for AirVantage
cloud service
Apache member, Eclipse IoT committer
Californium, Wakaama,
Leshan open-source Lightweight M2M server
Tinkerer: electronics, reversing, Linux

3.
Photo Credit:https://www.flickr.com/photos/90514086@N00/952121271/ CC by-nc-sa

4.
Agenda
M2M/IoT application protocols (XMPP, MQTT)
Web-of-things (CoAP)
IoT protocol security
Device management (TR-069, OMA-DM, OMA-LwM2M)
Impact on IoT architectures

5.
Let’s start with..
QUESTIONS!

6.
Questions
Know MQTT?

7.
Questions
Use MQTT?

8.
Questions
Know or use
CoAP?

9.
Questions
Device management:
OMA-DM,
Lightweight M2M
or TR-069?

10.
Application protocols
XMPP
MQTT
CoAP

11.
XMPP
Chat protocol based on XML recycled for IoT
XEP-0322 (PDF) Efficient XML Interchange (EXI) Format Standards - 2014-03-10
XEP-0323 (PDF) Internet of Things - Sensor Data - Experimental - 2014-04-07
XEP-0324 (PDF) Internet of Things - Provisioning - Experimental - 2014-05-21
XEP-0325 (PDF) Internet of Things - Control -Experimental 2014-04-07
XEP-0326 (PDF) Internet of Things - Concentrators - Experimental 2014-03-10

12.
XMPP
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='5'>
<node nodeId='Device02'>
<timestamp value='2013-03-07T19:31:15'>
<numeric name='Temperature' momentary='true'
automaticReadout='true' value='23.4' unit='°C'/>
</timestamp>
</node>
</fields>
</message>

13.
MQ Telemetry Transport
Killer protocol for M2M applications
Connect everything with a central broker
Content agnostic
Simplicity is MQTT feature #1

14.
MQ Telemetry Transport
- a sensor pushes telemetry values on topics
greenhouse/42/temperature
greenhouse/42/humidity
greenhouse/42/luminosity
- actions are on another topic
greenhouse/42/open-the-roof
- payload format is free (json,binary,whatever..)

15.
MQTT security
- Username and password
- TLS on top of the TCP stream

16.
MQ Telemetry Transport @ Eclipse IoT
Write your first MQTT application today :)
Mosquitto lightweight broker
Moquette Java based broker
Paho clients Java, C/C++, Go, Python, Lua
Ponte bridge MQTT, CoAP and HTTP
Kura Java OSGi application framework

17.
M2M: devices to a server
Server Server

18.
IoT: devices on Internet
Internet

19.
Web of things
IP address for everything!
6LoWPAN on 802.15.4, Bluetooth LE
Small IPv6 stack in battery powered devices
Create mesh network with RPL (RFC 6550)

20.
Web of things
REST for everything!
Sensor will live for decades
Applications will evolve
Things should expose dumb REST API, put the
behaviour in mashup applications

21.
Web of things

22.
CoAP
Constrained Application Protocol
Internet Eng. Task Force standard for IoT
Started around 2010!
Final RFC 7252 published

23.
CoAP
Co: Constrained
Simple to encode/decode: target 1$ 8bits MCU
100K Flash, 10K RAM

24.
CoAP
Co: Constrained
HTTP and TCP are not a good fit, use UDP
Low power networks

25.
CoAP
AP: Application Protocol
RESTful protocol designed from scratch
Transparent mapping to HTTP
Additional features of M2M scenarios
GET, POST, PUT, DELETE
URIs and media types
Deduplication
Optional retransmissions
Observation, SMS

26.
CoAP
Protocol structure
Binary protocol
● Low parsing complexity
● Small message size
Options
● Numbers with IANA registry
● Type-Length-Value
● Special option header
marks payload if present

27.
CoAP
Discoverability
Based on Web Linking (RFC5988)
Extended to Core Link Format (RFC6690)
GET /.well-known/core
</config/groups>;rt="core.gp";ct=39,
</sensors/temp>;rt="ucum.Cel";ct="0 50";obs,
</large>;rt="block";sz=1280
;title="Large resource"
Decentralized discovery: Multicast Discovery
Infrastructure-based: Resource Directories

28.
CoAP
Security
Based on DTLS (TLS/SSL for Datagrams)
Focus on Elliptic Curve Cryptography (ECC)
ECDH, ECDSA, AES
Hardware acceleration for IoT devices

29.
Californium
CoAP @ Eclipse IoT
Pure Java library
DTLS PSK/RPK/X509
Unconstrained:
For large devices or cloud services
http://eclipse.org/californium

30.
M2M/IoT Protocol security

31.
IoT/M2M protocol security
TLS for TCP (RFC 5246)
DTLS for UDP (RFC 6347)
Rolling your own is still not recommended :)

32.
TLS/DTLS complexity?
It’s customizable:
X.509 certificate: certificate with chain of trust (CA & PKI)
Raw-Public-key: only private/public key
Pre-Shared-Key: symmetric keys without forward secrecy

33.
TLS/DTLS complexity?
Arduino Uno can run CoAP/MQTT
But not in a secure way :(
ROM/RAM cost estimation for (D)TLS:
http://www.ietf.org/id/draft-ietf-lwig-tls-minimal-01.txt

34.
(D)TLS Pre-Shared-Key mode
+----------------------+-----------------+
| | DTLS |
| +--------+--------+
| | ROM | RAM |
+----------------------+--------+--------+
| State Machine | 8.15 | 1.9 |
| Cryptography | 3.3 | 1.5 |
| DTLS Record Layer | 3.7 | 0.5 |
+----------------------+--------+--------+
| TOTAL | 15.15 | 3.9 |
+----------------------+--------+--------+
Table 1: Memory Requirements in KB

35.
(D)TLS Raw Public Key mode
+----------------------------+---------------+
| Cryptographic functions | Code size |
+----------------------------+---------------+
| MD5 | 4,856 bytes |
| SHA1 | 2,432 bytes |
| HMAC | 2,928 bytes |
| RSA | 3,984 bytes |
| Big Integer Implementation | 8,328 bytes |
| AES | 7,096 bytes |
| RC4 | 1,496 bytes |
| Random Number Generator | 4,840 bytes |
+----------------------------+---------------+

36.
(D)TLS Raw certificate mode
You need to add:
ASN.1 parser
X509 certificate check code
Revocation?

37.
TLS for embedded
It’s still a challenge on some platform
IETF DICE working group https://datatracker.
ietf.org/wg/dice/
But weirdly TLS PSK is not used
Certificate revocation is also a mess for IoT

38.
Open-source DTLS implementation
TinyDTLS: http://tinydtls.sourceforge.net
MIT licensed embedded friendly
Lua binding: https://github.com/sbernard31/luadtls
Eclipse Californium Scandium:
A Java implementation of DTLS
https://github.com/eclipse/californium.scandium

39.
More security challenges ;)
Provisioning your key from the factory and
pushing them on the server...
... for million of devices with different keys
… and with the capability of changing the keys
over-the-air

40.
Device Management

41.
Device management
Monitor, configure, secure, and update your
devices
All you need for operating a fleet of IoT devices
Not tied to your application

42.
Interoperability is the key
You don't know yet what hardware will power
your IoT projects on the field
but you MUST be able to do management in a
consistent way

43.
D.M. protocols
Usual suspects:
TR-069
OMA-DM
Lightweight M2M

44.
TR-069
Bidirectional SOAP API for :
broadband modems, gateway, set-top-boxes
Configure, monitor, firmware upgrades.
Yeah SOAP : HTTPS and XML :(
Not wireless friendly

45.
OMA-DM
An Open Mobile Alliance standard for Device
Management
Targets mobile phone terminals but can be
used for M2M
Mean to be used by mobile network operators.

46.
OMA-DM features
Read, write configuration or monitoring nodes.
Trigger remote commands (Exec)
FUMO: Firmware Update Management Object
SCOMO:
Software Component Management Object

47.
OMA-DM flaws
Phone oriented
HTTP+XML (or binary XML) not compact at all

48.
OMA-DM flaws: Hello world :)
<?xml version="1.0" encoding="UTF-8"?>
<SyncML xmlns="SYNCML:SYNCML1.2">
<SyncHdr>
<VerDTD>1.2</VerDTD>
<VerProto>DM/1.2</VerProto>
<SessionID>D101</SessionID>
<MsgID>1</MsgID>
<Target>
<LocURI>http://na.airvantage.net</LocURI>
</Target>
<Source><LocURI>IMEI:1234567890</LocURI></Source>
<Meta>

49.
<MaxMsgSize>20480</MaxMsgSize>
<MaxObjSize>512000</MaxObjSize>
</Meta>
</SyncHdr>
<SyncBody>
<Alert>
<CmdID>1</CmdID>
<Data>1201</Data>
</Alert>
<Replace>
<CmdID>2</CmdID>
<Item>
<Source><LocURI>./DevInfo/DevId</LocURI></Source>
<Data>IMEI:1234567890</Data>
</Item>

50.
<Item>
<Source><LocURI>./DevInfo/Man</LocURI></Source>
<Data>Sierra Wireless</Data>
</Item>
<Item>
<Source><LocURI>./DevInfo/Mod</LocURI></Source>
<Data>SL6087</Data>
</Item>
<Item>
<Source><LocURI>./DevInfo/DmV</LocURI></Source>
<Data>Sierra Wireless OMC v2.0</Data>
</Item>
<Item>
<Source><LocURI>./DevInfo/Lang</LocURI></Source><Data>en</Data>
</Item>
</Replace>
<Final />
</SyncBody>
</SyncML>

51.
OMA-DM: Helloworld server reply
<?xml version='1.0' encoding='UTF-8' standalone='no' ?>
<SyncML xmlns="SYNCML:SYNCML1.2">
<SyncHdr><VerDTD>1.2</VerDTD><VerProto>DM/1.2</VerProto><SessionID>D101</SessionID>
<MsgID>1</MsgID>
<Target><LocURI>IMEI:1234567890</LocURI></Target>
<Source><LocURI>http://na.airvantage.net</LocURI>
<LocName>AIRVANTAGE-SERVER</LocName>
</Source>
</SyncHdr>
<SyncBody>
<Status>
<CmdID>5</CmdID><MsgRef>1</MsgRef><CmdRef>0</CmdRef><Cmd>SyncHdr</Cmd>
<Chal><Meta>
<Format xmlns="syncml:metinf">b64</Format>
<Type xmlns="syncml:metinf">syncml:auth-MAC</Type>
XML QUOTA EXCEEDED..

52.
OMA-DM security flaws
Weak security (MD5-HMAC) on top of HTTP
Use full HTTPS for higher grade security
Complex to implement correctly, no streaming
due to HMAC
Unnecessary complex protocols is the safest
way to security holes

53.
OMA-DM
But works :)
Your mobile phone is managed using OMA-DM

54.
OMA Lightweight M2M
A reboot of OMA-DM but for M2M
Built on top of CoAP
REST API for device management

55.
Lightweight M2M: API
Security
Device
Server
Connectivity monitoring
Connectivity statistics
Location
Firmware
The objects have a numerical identifier.

56.
Lightweight M2M: URL
/{object}/{instance}/{resource}
Examples:
"/6/0" the whole position object (binary
record).
"/6/0/2" only the altitude.

57.
Lightweight M2M: API
You can define your custom objects
Published or not
Structure is discovered using the CoAP link
object format (RFC 6690)

58.
Lightweight M2M: bootstrap
Initial keying and configuration
Well defined security lifecycle
How to update credential and security scheme
Keying from factory, smartcard, or over-the-air

59.
Lightweight M2M: bootstrap
Device can go out of factory with just BS
credential
When it goes live the BS server provisions the
DM keys
Future proof, and the BS server can be really
robust

60.
Eclipse Wakaama
http://eclipse.org/wakaama
A C library for implementing LWM2M
Embedded friendly
Lua binding for Wakaama:
https://github.com/sbernard31/lualwm2m

61.
More Lightweight M2M open source
Leshan A Java implementation of LWM2M
Server library based on Eclipse Californium
Server UI
http://github.com/jvermillard/leshan

62.
LWM2M Demo
SHOWTIME!

63.
Protocol convergence
M2M/IoT is not a simple problem
Security and provisioning are really the hardest
ones
Try hard to reduce the number of protocols to
make your life easier!

64.
Burning in IoT hell: Mixing protocols
Cloud servers
OMA-DM
Radio module
2G/3G/LTE
ZigBee/6LowPan
WiFi, etc..
App1
Linux O/S
Supervisor
App2
App3
Low power
App
OMA-DM
MQTT/CoAP
Ad-hoc
TR-069
Network
Operator

65.
LWM2M + CoAP
LWM2M provide device management and
security workflow for CoAP application using
the same protocol!
Huge simplicity and security win!

66.
Key takeaways
Break silos: embrace the web-of-things
Think security first, it’s your biggest challenge
Use standards for device management and
keying
CoAP + LWM2M for your next IoT application!

67.
Thanks!
Twitter: @vrmvrm
E-mail: jvermillard@sierrawireless.com
Creative Commons – Attribution (CC BY 3.0)
Microchip designed by Nicolò Bertoncin from the Noun Project
Cloud designed by James Fenton from the Noun Project
Secure by Charlene Chen from The Noun Project
Chat by Icomatic from The Noun Project
Microchip designed by Mario Verduzco from the Noun Project
Certificate designed by Charlene Chen from the Noun Project