IoT and M2M for Software Developers

IoT and M2M
for software developers
Pascal BODIN
31-Jan-2015
V20150131https://creativecommons.org/

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contents
part 0 foreword
part 1 some use cases
part 2 some definitions
part 3 overall architecture
part 4 devices
part 5 central side
part 6 communication protocols
part 7 project leading perspective

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0. foreword
part 0.1 who I am
part 0.2 why we won't speak about software only

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who I am
 Pascal Bodin – Orange Labs – Sophia-Antipolis, France
– Orange Software Expert
– Orange Labs Products & Services Senior Software Developer
 10 years as M2M and IoT project leader and software engineer at Orange
Labs
 before this:
– 4 years as co-founder + system developer + co-manager - home computing
– 14 years as co-founder + system developer + manager - M2M/IoT
– 4 years as team manager at France Telecom R&D
– 10 years as software engineer (McDonnell Douglas, DEC)
(several periods with 2 simultaneous jobs...)

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why we won't speak only about software
 IoT/M2M system:
– devices
– connections between devices and real world
– various types of networks
– huge number of different use cases
– user needs often not well known
– agility is OK for software, but what about hardware?
 => a global view is required

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taxi dispatch
Taxis waiting at taxi stand
Cruising taxi
Central dispatch office
Sector 1
Sector 2
Customer

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environmental monitoring

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remote monitoring of copy machines

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let's share same vocabulary
central sideremote side
machine
vehicle
etc.
(embedded)
device
gateway
central
system
user
administrator
enterprise
information
system

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IoT/M2M definitions? - 1/3
 The Internet of Things (IoT) is the interconnection of uniquely identifiable
embedded computing devices within the existing Internet infrastructure.
[Wikipedia - 13-Jan-2015]
 The Internet of Things (IoT) is the network of physical objects that contain
embedded technology to communicate and sense or interact with their internal
states or the external environment. [Gartner - 13-Jan-2015]
 A global infrastructure for the Information Society, enabling advanced
services by interconnecting (physical and virtual) things based on, existing
and evolving, interoperable information and communication technologies. [ITU-T -
04-Jul-2012]
 Industrial IoT is a universe of intelligent industrial products, processes and
services that communicate with each other and with people over a global
network. [Accenture - 14-Oct-2006]
 IoT could mean almost anything. In some ways it is better to think of it as
the internet of everything. [The Guardian - 06-Nov-2014]

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 M2M refers to technologies that allow both wireless and wired systems to
communicate with other devices of the same type. [...] M2M is considered an
integral part of the Internet of Things. [Wikipedia - 15-Jan-2015]
 M2M is about connecting a device to the cloud, managing that device, and
collecting machine and sensor data. [...] IoT represents things connecting
with systems, people and other things. [Axeda - 22-Jan-2014]
 M2M is what provides The Internet of Things with the connectivity that enables
capabilities, which would not be possible without it. [Telefónica - 14-Oct-2013]
 Like M2M, most solutions that people call "IoT" are just SCADA-based solutions
with a less technical interface and/or explanation. [Novotech - 24-Feb-2014]

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 to summarize
many different definitions
most of them focus on (communication) technologies
 acronym means buzz
IoT and M2M acronyms are relatively new
IoT/M2M systems existed long before acronyms
acronyms are successful because they simplify reality
 reality
on one side: (lot of) technologies
on the other side: (large diversity of) user needs
 always ask more details...
...to someone using IoT/M2M acronyms!

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3. overall architecture

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architecture
 let's consider a feature-rich example, with some specific characteristics:
– (human perceived) real-time
– asynchronous downlink messages
– data + voice
 looking at such a system lets understand architecture more easily

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architecture
 our example system: a taxi dispatch system
 some functions:
– customer request allocated to the best taxi
– taxi driver acknowledgement
– taxi ride follow-up
– credit card payments
– general messages (e.g. « speed camera at... »)
– personal messages (e.g. « call your wife back »)
– security alarm, with audio monitoring
– taxi locating
– driver can display taxi distribution over the city
– driver can display request distribution over the city
– etc.

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architecture
Taxis waiting at taxi stand
Cruising taxi
Central dispatch office
Simplified dispatch algorithm
· city is divided in sectors
· one taxi stand at most per sector
· taxis can be waiting at a stand, or cruising
· taxi request dispatch:
• sector is selected (depending on customer
address)
• if taxis waiting at stand, first taxi complying with
services requirements is selected
• if stand is empty, a cruising taxi is selected
(usually the nearest one)
• if no cruising taxi in sector, search is broadened
to neighbouring sectors
• etc.
· selected taxi driver must acknowledge the request
Sector 1
Sector 2

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architecture
To device: are you really here? If yes, here is a request for the driver
From device to dispatch office: yes, I'm here
Displayed to driver:
Service
requirements.
Do you accept them?
Displayed to driver:
Address.
Do you accept the request?
From driver to dispatch office: yes, I accept the request
Request allocated to taxi 1
Taxi 1
To other taxis at same stand: request allocated to taxi 1
customer request dispatch

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architecture
 at a technical point of view:
– uplink and downlink messages, in (human perceived) real-time
– non trivial application code in embedded/onboard device
– different data transport services:
– without acknowledge
– with acknowledge
– unicast
– broadcast
– voice
– tight coupling between embedded application and central application

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architecture
Central sideRemote side
OS
embedded device
communication services - remote
application software - remote
OS
PC / serverperipherals
communication services - central
software components - centralsoftware components - remote
application software - central
OS API
communication services APIcommunication services API
OS API
components APIscomponents APIs
communication protocols
components protocols
application protocols
Customer-dedicated
integration
Technical components
Communication
Execution platforms

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architecture
 communication layer:
– bidirectional messaging, with/without ack, unicast, broadcast
– voice call
– « broadcast »
– etc.
 technical components layer (almost generic)
– mission dispatch handling
– alarm with end to end acknowledgement
– software odometer
– etc.
 application layer:
– adaptation to end-user needs
 this is an ideal view!

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4. devices
part 4.1 architecture
part 4.2 important microcontroller characteristics
part 4.3 interfacing with peripherals
part 4.4 connectivity
part 4.5 positioning
part 4.6 software development

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architecture
communication
module
microcontroller
(memory)
(embedded) device
interfaces
location
module
user interface
communication
network

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example
microcontroller
communication
module
location
module
analog
inputs
digital I/O

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communication module - 1/2
 communication module can be managed as a peripheral of the
microcontroller

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communication module - 2/2
 communication module can host application software

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4. devices

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important microcontroller characteristics - 1/2
 what is a microcontroller?
– on same chip: CPU + (some) memory + clock generator + peripherals
 architecture:
– von Neumann, Harvard, modified Harvard
– one core or multicore
 memory types and sizes:
– read-only memory (program): ROM/PROM/EPROM/EEPROM/Flash...
– read/write memory (data): RAM/SRAM/DRAM/MRAM/FRAM...
– data memory and program memory can be separated
 memory width:
– 4-bit, 8-bit, 16-bit, 32-bit
– 8-bit for data, 12-bit for program
– etc.

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important microcontroller characteristics - 2/2
 processing power
– depends on clock speed and architecture
– options: floating point operations, digital signal processing, etc.
 power consumption
– various low-power modes
 cost
 supporting hardware tools
– development board
– programmer / debugger
– open source schematic
 supporting software tools
– integrated development environment
– open source code
 support

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4. devices

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interfacing with peripherals - 1/8
 peripheral: any device not being part of the IoT/M2M device we are
considering, and attached to it
 sensors: pressure, temperature, light level, heat, magnetic field, airflow, tilt,
acceleration, switch, push button, etc.
 actuators: relay, motor, stepper motor, servomotor, etc.
 other devices: printer, display, On-Board Diagnostics connector, RFId tag
reader, etc.
 interface can be wired or wireless.

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 general purpose digital input/output (GPIO):
– read or set a voltage (high / low)

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 analog to digital converter (ADC):
– converts an analog voltage to a digital value
 digital to analog converter (DAC):
– converts a digital value to an analog voltage

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 serial bus: serial interface / V.24 / RS-232
– minimum 3 wires: transmitted data, received data, signal ground
– additional wires for control signals (request to send, ready for sending, data
set ready, calling indicator, etc.)
– voltage level:
– V.28: -15V / +15V or
– board voltage
– distance: < 15 m

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 serial bus: SPI (Serial Peripheral Interface)
– four-wire synchronous serial bus
– master/slave
– short distance
– for sensors (temperature, pressure, etc.)
– for LCDs
– etc.
SPI
Master
SCLK
MOSI
MISO
SS1
SS2
SS3
SPI
Slave
SCLK
MOSI
MISO
SS
SPI
Slave
SCLK
MOSI
MISO
SS
SPI
Slave
SCLK
MOSI
MISO
SS

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 serial bus: I2C (Inter-Integrated Circuit)
– two-wire synchronous serial bus
– multi-master
– short distance
– same applications than for SPI

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 serial bus: CAN (Controller Area Network)
– mainly for vehicles (e.g. OBD)
– often: 4 wires (including power)
– multi-master
– distance: up to several hundreds of meters (with “low” bit rate)

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 Bluetooth:
– originally designed to replace serial cables – personal area network (PAN)
– range: less than 100 m
– many profiles
– Bluetooth Low Energy (part of V4.0)

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at a software point of view
 writing low-level code to handle interfaces:
– serial interface: not too complex (see interrupts + ring buffer)
– SPI, I2C: not too complex either
– CAN: more complex
– Bluetooth: forget about it! Use an existing driver.

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what can we do with a microcontroller? - 1/2
taxi driver
taxi central dispatch office
taxi
repeater

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what can we do with a microcontroller? - 2/2
 with a Freescale 68HC11 (25+ years old, still in use)
– 8 KB RAM, 32 KB Flash, 8 bits, 2 MHz
 embedded code:
– drivers: LCD, transceiver and handset serial buses, GPS receiver, data
storage, I/O
– cell-roaming
– application-layer protocol stack
– ride handling
– lists of busy and free taxis per sector
– lists of booked rides per sector
– alarm handling (data + voice)
– start and end of service
– alarm pedal, taximeter
– etc.

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4. devices

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connectivity
 allows for data transfer with a remote system (≠ peripheral)
 wireless:
– PMR (Private/Professional Mobile Radio)
– low power / short range, on unlicensed frequencies
– 2.5 G / 3G / 4G
– satellites
– Wi-Fi
– Bluetooth, ZigBee, Z-Wave
 wired:
– LAN (Local Area Network)
– leased lines
– PSTN (Public Switched Telephone Network)
– ADSL (Asymmetric Digital Subscriber Line)

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connectivity
communication
module
microcontroller
(memory)interfaces
location
system
user interface
communication
network
command + data
interface

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connectivity
 commands, events and data:
– configure
– start connection
– stop connection
– connection status
– send data
– received data
– incoming call
– etc.
 interface definition depends on
– communication module <=> network technology
– device architecture (microcontroller + comm. module ≠
smartphone/programmable module)

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connectivity - example 1
 for an unlicensed RF module (Digi XTend)
– serial interface
– commands and data sent in frames
– binary protocol
0x7E
Start delimiter
byte 1
MSB LSB
Length
bytes 2, 3
data
Frame data
bytes 4 - n
CS
Checksum
byte n + 1
data: transmit request, transmit status, received data, etc.

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connectivity - example 2
 AT commands:
– quite common: 3GPP communication modules, modems, etc.
– ASCII protocol
– command / response – intermediate result codes – unsolicited result codes
– example for 3G:
– define context number 3 with given APN, requesting IP protocol:
communication
module
communication
network
AT+CGDCONT=3,”IP”,”orange.m2m.sec”
OK

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connectivity - 3GPP networks - 1/2
 APN (Access Point Name):
– name of gateway between 2.5G / 3G / 4G network and another network
(usually the Internet)
– defined by the operator
– for the Internet, defines following gateway characteristics:
– static or dynamic IP address
– public or private IP address
– allowed protocols (TCP, UDP, etc.)
– allowed ports

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connectivity - 3GPP networks - 2/2
mobile network
the Internet
APN
1 - register
2 – define and activate context
=> comm. module known
to network
=> IP address assigned to
comm. module
3 – start a PPP session
=> IP address assigned to
remote device
communication
module
device
AT commands

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connectivity - comparison - 1/2
Techno Shared Range Latency Setup time
PMR no from 30 km up to wide
area
depends on architecture 0
low power yes up to 10 (40) km depends on architecture 0
2.5G/3G yes wide area from 100 ms up to 1 s from 2 s to 5 s
4G yes wide area 50 ms 1 s
satellites
geo
yes global 800 ms to 60 s depends
satellites
LEO
yes global min depends
Wi-Fi yes local ms s

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connectivity - comparison - 2/2
Techno Addressability TX power Equipment cost Comm.
cost
PMR full W 100s € 0 €
low power full mW 10s € 0 €
2.5G/3G restricted W 100s € flat rate
4G restricted W 100s € --> 10s € flat rate
satellites
geo
restriced W 1000s € high
satellites
LEO
restricted W 100s € high
Wi-Fi full mW 10s € 0 €

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4. devices

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positioning - 1/5
 GNSS: Global Navigation Satellite System
 USA: GPS
– 31 operational satellites (24-Dec-2013)
– accuracy documented as better than 8 m with 95% confidence level
 Russian Federation: GLONASS
– 23 operational satellites (22-Feb-2014)
 Europe: Galileo
– 6 satellites with 2 on incorrect orbits (22-Aug-2014) - first fix: 12-Mar-2013
– target: 30 satellites
 China: BeiDou ( 北斗 )
– 10 satellites – operational over China
– target: 5 GEO satellites + 30 MEO satellites
 Japan: QZSS, India: IRNSS

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positioning - 2/5
 example of accuracy:
– GPS receiver indoor, not far from a window => lower reception quality
– one location every 2 s, for 15 minutes
– several locations are more than 60 m far from the real location

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positioning - 3/5
communication
module
microcontroller
(memory)interfaces
location
system
user interface
communication
network
command + data
interface

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positioning - 4/5
 interface:
– usually: serial (V.28 or board voltage)
– usually: implements subset of NMEA 0183 standard
– most manufacturers provide their own protocol:
– SiRF (then CSR, now Samsung) – u-blox - SkyTraq – ST – Broadcom – etc.
$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47
Where:
GGA Global Positioning System Fix Data
123519 Fix taken at 12:35:19 UTC
4807.038,N Latitude 48 deg 07.038' N
01131.000,E Longitude 11 deg 31.000' E
1 Fix quality: 0 = invalid
1 = GPS fix (SPS)
2 = DGPS fix
3 = PPS fix
4 = Real Time Kinematic
5 = Float RTK
6 = estimated (dead reckoning) (2.3 feature)
7 = Manual input mode
8 = Simulation mode
08 Number of satellites being tracked
0.9 Horizontal dilution of position
545.4,M Altitude, Meters, above mean sea level
46.9,M Height of geoid (mean sea level) above WGS84
ellipsoid
(empty field) time in seconds since last DGPS update

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positioning - 5/5
 it's possible to increase GNSS accuracy
– differential GPS, SBAS (WAAS, EGNOS, GAGAN, MSAS), A-GPS, RTK
 network positioning:
– trilateration (several time measures)
– triangulation (several angle measures)
– cell identification
– “fingerprinting”
– more ?
 dead reckoning: first known position then inertial sensor fusion
(accelerometer + magnetometer and filtering)
 outdoor / indoor?

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4. devices

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development environment
● source code edition
● compilation / link
● simulation
● debugging
● load / run
● emulation
● debugging
LPCXpresso
VxWorks
GNU toolchain
TASKING
...
PC running Linux,
OSX, Windows
microcontroller board
Atmel Studio

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execution environment
Morpheus3
VxWorks
RTX
OS
RTOS
specific runtime
interrupt handlers
+ background task
...
...
...
Esterel
Lustre
bare metal
Ada

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bare metal - 1/9
 let's look more closely at a microcontroller architecture

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bare metal - 2/9
 some events generated by peripherals
input level changed
character sent
character received
counter limit reached
end of conversion
bit received
frame received
frame sent
watchdog timeout

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bare metal - 3/9
 an event generates an interrupt
 attach an interrupt handler to the interrupt you want to handle
 example: analog to digital conversion
time
background task
end of
conversion
interrupt handler
background task
interruption
save
context
restore
context
start
conversion

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bare metal - 4/9
 usual OS services not available:
– process
– thread
– synchronized access to shared resources (memory, peripherals)
– inter-thread communication
– device drivers
– file system
– etc.

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bare metal - 5/9
 it's less complex than it appears for small applications
 very useful for some classes of requirements:
– (very) small memory footprint
– low power consumption
– low cost
 available tools:
– some commercial or open source code is available (flash file system, TCP/IP
stack, etc.)
– macro definitions preventing use of assembly language
– hardware debugger with trace capture

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bare metal - 6/9
 available tools (cont'd):
– well known design patterns:
– ring buffer
– finite state machine (FSM)
– etc.
– ring buffer and FSM can be used even in OS context

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outPtr inPtr
data
bare metal - 7/9
 ring buffer (or circular buffer):
– fixed-size memory array, used as an interface between a producer and a
consumer
– pointer outPtr points to first non empty element
– pointer inPtr points to first empty element
– to get next element: read outPtr, read data, increment outPtr
– to put a new element: read inPtr, write data, increment inPtr
– when at the end of the array, pointer is reset to start of array

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bare metal - 8/9
 ring buffer (cont'd):
– a ring buffer is a FIFO (First In, First Out)
– when put rate is greater than get rate, buffer gets full:
– new data overwrites oldest one, or
– put is not performed
– beware: put and get operations must be atomic
 examples of use:
– receive buffer for a serial interface
– message queue for communication between two different pieces of code

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state S1
state S2
event E1 (+ condition C1)
actions A to perform
bare metal - 9/9
 finite state machine:
– an abstract machine that can be in one of a finite number of states
– the machine is in only one state at a time (current state)
– transition from one state to another one is triggered by an event (possibly
guarded by a condition)
– one possible way to graphically depict an FSM:

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RTOS
 an RTOS (or an OS) provides many services:
– tasks
– task notifications
– queues
– semaphores
– mutexes
– timers
– memory protection
– etc.
 easier to write feature-rich applications but:
– experience is still required
– debugging can be more complex (but easier as well!)
– an RTOS must be configured for the hardware platform
– larger footprint
– etc.

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5. central side
part 5.1 architectures
– functional view
– architectures
– communication server
– databases
– GIS
– User Interface
part 5.2 platforms
part 5.3 developing with platforms

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functional view
communication
network
communication
server
application
software
data
persistence
UI (user
interface)
GIS (Geographic
Information System)
device
management
user
management

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architectures
 previous architecture is not a reference one!
 architecture view is always influenced by architect's experience and activity
– mine is the one of an integrator having to build full vertical systems
– platform architects have a different view
– standardization organisations have another one
– telecom operators have another one
– etc.
 functional and physical architectures depends on:
– number of devices
– security requirements
– position in value chain (to be seen later)
– etc.

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communication server - 1/4
 communication server:
– provides an interface to communicate with devices
– may handle several different network technologies
– switching to another network technology or supporting a new one should be
easy and rapid
– other usual requirements:
– security concerns: authentication, integrity, privacy, (non-repudiation)
– reliability
– scalability
– etc.

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 example:
– for PMR or unlicensed radio
antennas
transceivers
+ modems
communication
server

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 example:
– for 3GPP
communication
server
Internet

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 3GPP example (cont'd):
– uplink (from devices to server):
– server IP address must be reachable => public or VPN
– downlink:
– device IP address characteristics depend on APN
– static or dynamic?
– public or private?
– several solutions depending on user need and required genericity:
– device initiates and maintains a TCP session
– server sends an SMS to device, requesting its connection
– devices connects periodically
– private APN => VPN
– etc.

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databases
 3 main technologies:
– relational database
– object database
– NoSQL database
 another dimension to be considered sometimes:
– spatial database (but GIS function can be provided as a service)
 a question may arise:
– do application data have to be separated from “technical” data?
– there is no one right answer
 another question:
– should all device generated data be mirrored in the central database?
– again: there is no one right answer

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Geographic Information Systems - 1/4
 some applications need
– to perform spatial operations and / or
– to display spatial information
 at a technical point of view, two different elements:
– functions:
– spatial queries against spatial database
– spatial libraries
– data:
– digital maps
– georeferenced data
 at an architectural point of view:
– web GIS
– rich client

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 all-in-one (functions + data) web GIS:
– Google Maps JavaScript API
– Bing Maps APIs
– etc.
 functions only web GIS:
– MapServer (Open Source)
– GeoServer (Open Source)
– etc.
 functions only rich client GIS:
– GRASS GIS (Open Source)
– QGIS (Open Source)
– uDig (Open Source)
– etc.

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 data:
– OpenStreetMap (Open Source)

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 many providers of commercial products:
– rich client / desktop GIS
– web GIS
– data (vector, bitmap, additional layers)
 GIS is a complex matter:
– do not try to reinvent the wheel
– take some time to get some experience

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User Interface
 as for GIS: web or rich client
 web:
– ⊕ good for large number of distributed users
– ⊕ can be good for supporting multi-device / multi-OS
– ⊕ good for software updates
– ⊖ usually bad for user-perceived response time
– ⊖ usually bad for « real-time » or complex user interfaces
– ⊖ usually bad for license cost
– etc.
 rich client:
– almost the other way round...
 mixing the two of them can be a good solution

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central side
– functional view view
– architectures
– databases
– GIS
– User Interface
part 5.2 platforms

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platforms - 1/4
 beware: the word « platform » may have different meanings
– software development framework
– software application providing communication (and possibly management and
storage) services
– a hosted application providing above services
– hardware system
– hardware system and associated software stack
– etc.
 in what follows: hosted application

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platforms - 2/4
 functions usually provided by a platform (as seen by a user):
– device provisioning
– device management
– device authentication
– support of some communication protocols
– user authentication
– data persistence (raw data or decoded data?)
– device groups
– user groups
– easy way to add new communication protocols
– etc.
 two logical interfaces: one for devices, one for applications

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platforms - 3/4
remote system central system
platform
platform
layers solving
customer problem
layers solving
customer problem
customer
pays for this,
not for the
platform
relative sizes of software
layers,
for a complex system

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platforms - 4/4
 perceived value is often not in the platform
 a platform may prevent from using some devices (which do not implement a
supported protocol)
 a platform creates a protocol break
 when updating the platform, ALL users are impacted
 developing a communication layer + minimum device management is not
complex for an experienced team
 => think twice before deciding on using a platform
 anyway, using a platform may be very nice, for some (simple) applications,
to demonstrate a new service, or for very large sets of devices
 at least 60 platforms today on the market (including some Open Source'd)
– http://www.monblocnotes.com/node/1979

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central side
– functional view view
– architectures
– databases
– GIS
– User Interface
part 5.2 platforms

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platforms - 1/2
 often, two different logical interfaces:
– devices
– central application

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platforms - 2/2
 usual steps, to use a platform for a new development:
– register
– check list of supported devices, and select one
– download client source code or library
– build an « Hello World » client (send/receive data)
– test it
– check send/receive data using available web application
– download central application source code or library
– build an « Hello World » application (send/receive data)
– test it
– test the whole system

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6. communication protocols
part 6.1 introduction
part 6.2 UDP, TCP
part 6.3 MQTT
part 6.4 CoAP
part 6.5 other protocols

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introduction
 communication protocol:
a system of digital rules for data exchange within or
between computers [Wikipedia]
 remember connectivity part? We saw two protocols:
– Digi XTend
– AT commands
 used to control communication module
 once communication module (and communication link) is in the right state,
data can be exchanged with remote application

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introduction
 some characteristics of protocols:
– stream-oriented or message-oriented
– data integrity
– ordered delivery
– duplicate detection
– error detection
– error recovery
– addressing
– etc.
 protocol stack: piece of software that implements a protocol

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protocols - 1/5
 piece of advice:
– reuse existing protocol and associated stack as often as possible
– be sure that chosen protocol fulfils your needs
– be sure you use the protocol in the correct way
 example: TCP
– TCP is a stream-oriented protocol:
– “Hello world” can be received as “Hell” and then “o world”
– “Hello” and then “ world” can be received as “Hello world”
– => framing is required (see next slide)
– to transmit a file, rely on TCP integrity mechanism: do not use application
ack for every n bytes
– TCP disconnection is not signalled: use a keep-alive mechanism if
required

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frame
 frame coding/decoding:
– ASN.1: defined 30 years ago by CCITT (now ITU-T) – not so used in
M2M/IoT...
– Google re-invented a solution in 2008: Protocol Buffers – not so used either in
M2M/IoT...
– advantages:
– reliable solutions
– data endianness independency
– transparent serialization/deserialization
– forward compatibility
– drawbacks:
– some complexity
– Protocol Buffers needs framing
– libraries in various languages to encode / decode frames
– not so difficult to define your own mechanism

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part 6.2 UDP, TCP
part 6.3 MQTT
part 6.4 CoAP

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UDP, TCP
 UDP, TCP:
– not specific to IoT/M2M
– acronyms well known, functions not so well known
– remember: TCP is a stream-oriented protocol, not a message-oriented
one (framing is required)
– TCP disconnections are not signalled
– addressability:
– port and protocol filtering (3GPP networks for instance)
– public or private IP addresses
– static or dynamic IP addresses

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part 6.2 UDP, TCP
part 6.3 MQTT
part 6.4 CoAP

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MQTT
 MQTT:
– name comes from Message Queue Telemetry Transport
– but MQTT does not really queue messages, and is not restricted to telemetry
– current version: 3.1.1 (29-Oct-2014)
– originated from IBM and Arcom (now Eurotech) (1999)
– now maintained by OASIS Consortium (Organization for the Advancement of Structured
Information Standards)

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MQTT
 characteristics:
– client server publish/subscribe messaging transport protocol
– server side defines a message broker
– requires TCP as underlying protocol, or a protocol providing ordered, lossless,
bi-directional connections
– quality of service for message delivery:
– at most once, at least once, exactly once
– notifies abnormal disconnections
– according to its specification:
– light weight, open, simple, easy to implement
– small code footprint
– security, if required:
– username and password
– SSL
– application-level encryption

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MQTT
 example of use case

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MQTT
 MQTT implementations:
– Eclipse IoT - Paho project (open source)
– C/C++ clients
– MQTT-SN (Sensor Networks) C client
– Java J2SE client
– Android client (service)
– JavaScript client (uses WebSockets)
– Python client
– Go client
– C# client (.Net and WinRT)
– a sandbox server is available
– Eclipse IoT - Mosquitto project (open source)
– MQTT and MQTT-SN C server

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MQTT
 MQTT implementations (cont'd):
– HiveMQ:
– server
– interesting list of MQTT client tools
– etc.

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part 6.2 UDP, TCP
part 6.3 MQTT
part 6.4 CoAP

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CoAP
 CoAP:
– Constrained Application Protocol
– current version: June 2014
– designed and maintained by IETF (Internet Engineering Task Force) - RFC7252

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CoAP
 characteristics:
– designed for constrained nodes (8-bit microcontrollers)
– relies on UDP
– low header overhead
– low parsing complexity
– « web protocol »
– complies with REST architecture
– stateless HTTP mapping
– support URIs and content-type
– simple proxy and caching capabilities
– supports multicast
– security:
– DTLS (Datagram Transport Layer Security) bindings

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CoAP
 CoAP implementations:
– Eclipse IoT - Californium project (open source)
– core
– Scandium project: security
– Actinium project: server
– tools
– connector
– other implementations: check Wikipedia

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part 6.2 UDP, TCP
part 6.3 MQTT
part 6.4 CoAP

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other protocols
 Open Wireless Telematics Protocol
– designed by Mobile Devices
– for CloudConnect platform
– uses ASN.1
 M3DA
– open source protocol
– used by AirVantage platform (Sierra Wireless)
– uses Bysant serializer
 Cloud Connector
– designed by Digi
– for Etherios platform
 LWM2M (LightweightM2M)
– from OMA (Open Mobile Alliance) - for device management
 etc.
And XML/HTTP or JSON/HTTP?!
Why not? But think at data volume
and power consumption...

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other protocols
 LWM2M implementations:
– Eclipse IoT - Wakaama project (open source)
– C client and server

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project leading perspective
part 7.1 open or free or low cost hardware and software
part 7.2 ecosystem
part 7.3 standards
part 7.4 some concrete examples

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open or free hardware/software - 1/3
 many, many, many open source and/or free (or low cost) materials
 microcontroller boards:
– BeagleBone 46 € (Black)
– Arduino 36 € (Due)
– NXP LPCXpresso 20 € (LPC1115)
– Freescale FRDM KLxx 10 € (KL05Z)
– etc. (check http://monblocnotes.com/node/1849)
 electronics:
– http://www.cooking-hacks.com/
– http://www.seeedstudio.com/
– https://www.tindie.com/
– Farnell, Mouser, RS
– etc.

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 software development tools for devices:
– BeagleBone Black: Linux usual toolchain
– Arduino: Arduino IDE
– LPCXpresso: LPCXpresso IDE (Eclipse based)
– some components are closed
– FRDM KLxx: Kinetis Design Studio IDE
– etc.
 various software stacks:
– protocols (refer to previous slides)
– etc.

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 software (for central application):
– open source platforms
– FI-WARE
– IoTivity
– nimbits
– OpenIoT
– OpenRemote
– etc.
– protocol stacks: see previous slides
– additionally: GIS (see previous slides), relational databases (MySQL,
PostgreSQL, etc.), noSQL databases (Cassandra, CouchDB, etc.)
– etc.

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part 7.2 ecosystem
part 7.3 standards

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ecosystem - 1/4
 what we saw:
– many different use cases
– several different technologies
 => ecosystem and value chain are complex

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ecosystem - 2/4
 usually, value chain is depicted like this:

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ecosystem - 3/4
 more realistic view:
Software editor Middleware editor
Application software
component editor Object manufacturer
Positioning
technology provider
Radio terminal
manufacturer
Network operator Integrator Installer
Geocoded data
provider
Customer Service provider
Embedded OS editor
Customer's
customers
delivers to
not all links are presented
originally drawn for B2B systems

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ecosystem - 4/4
 many different type of activities
– it's quite common that one company runs several activities
 important activity: integration
– the integrator tries to get a working system!
 another important activity, often forgotten about:
– installation (at home, in a vehicle, in a factory...)
– bad installation => lot of glitches, very difficult to diagnose

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part 7.2 ecosystem
part 7.3 standards

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standards - 1/6
 some “old” standards:
– V.24, V.28, etc.
– MODBUS, Fieldbus, etc.
– SPI, I2C, etc.
 but that's really far from being enough
 let's dream:
– any remote system should be able to communicate with any
central system
– any central system should be able to communicate with any
central system
– any system receiving a new type of data should be able to know
whether it has to process this data, and/or what it means
(semantics, ontology)

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standards - 2/6
 in Europe: ETSI (European Telecommunications Standards Institute)
– M2M communications

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standards - 3/6
 most of ETSI standardization work has been transferred to oneM2M in
2012
 oneM2M is a global partnership project (China, Japan, Europe, North
America, etc.)
 OMA (Open Mobile Alliance) is member of oneM2M
 goal:
develop technical specifications which address the
need for a common M2M Service Layer that can be
readily embedded within various hardware and software

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standards - 4/6
 many other standardization organizations:
– Open Interconnect Consortium (OIC)
– Thread Group
– AllSeen Alliance
– Hypercat Consortium
– Industrial Internet Consortium (IIC)
– Global Standards Initiative on Internet of Things (IoT-GSI)
– ITU Joint Coordination Activity on IoT (JCA-IoT)
– oneM2M
– TIA TR-50
– Open Mobile Alliance (OMA)
– OMG Data-Distribution Service for Real-Time Systems (DDS)
– IEEE IoT Architecture Working Group

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standards - 5/6
 many other standardization organizations (cont'd):
– Internet Engineering Task Force (IETF)
– IPSO Alliance
– W3C Web of Things Community Group
– W3C Semantic Sensor Network Incubator Group
– ZigBee Alliance
– ULE Alliance
– Z-Wave Alliance
– etc. (see http://www.monblocnotes.com/node/2034)

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standards - 6/6
 Q: so many standards... What to do with them?
 A: what you want
 more seriously:
– for an integrator:
– try to use standardized interfaces and products
– stay informed

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part 7.2 ecosystem
part 7.3 standards

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usual difficulties
 a project must deliver a technical solution that matches user needs
 difficulties:
– user needs not defined correctly
– complex ecosystem
– unreliable communication network
– too many standards / lack of standards
– system distributed over several physical components
– electronics and software do not obey same life cycles
– some specific software expertise required
– high reliability sometimes required
– etc.
 following examples: how some difficulties were handled (or not)

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example - user needs - 1/3
 project: RFP for a waste collection management system
 time spent talking with the customer led project team to understand that
there was no need for real-time data transmission
 proposal: truck data downloaded by wire at the end of the day
– => lower operating cost than competitors' proposals
– contract signed, while the provider had no experience about waste
collection management system
 understand customer needs better than himself

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 project: RFP for a taxi dispatch system
 taxi drivers had no experience of a dispatch system
 neither the provider
 agreement about « agility »:
– minimum viable product delivered as soon as possible
– feedback from drivers and dispatch people
– => modification of some delivered functions
– => decision about new ones to be added
– => new version
– several successive versions
 be agile

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 project: RFP for a bus schedule checking system
 « big brother » feeling: bus drivers could decide to go on strike
– => first delivered functions were providing immediate value to bus
drivers (free voice calls, attack alarm)
– => no more problem with trade unions
 rapidly deliver value to the users

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example - technology - 1/4
 GPRS was documented as THE solution for packet data over GSM
networks
 one undocumented trap:
– connectivity reset by the operator on a periodic basis
 not a big deal for developers used to wireless technology
 but a problem for many developers used to LAN
 never assume things work as documented

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 for a taxi dispatch system:
– the provider ordered an onboard device from a very well known
company (new product)
– two design flaws appeared after first tests (HW + SW)
 no time for correction: a software workaround had to be implemented
 never assume things work as documented (bis)
 plan for contingencies

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 for corrected version of previous device, manufacturer introduced new
functions required by other customers
– => design too complex
– => cost too high
 it was decided to perform design in-house.
 costly effort:
– => skills ramp-up
– => development of an SDK + testing tools
 but return on investment:
– control over roadmap
– cost reduction by using device for all projects (some components not
assembled, depending on project)
– etc.
 control core technology

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 request to an electronic design company: design a low power consumption
device, sending some sensor data to a central application, on a periodic
basis.
 they designed a board with:
– a low power microcontroller
– a low power communication module
 but, to upload the few KB of data on a periodic basis, they used FTP
(instead of byte streaming over TCP for instance)
– => longer connections
– => data overhead
– => more power used!
 keep the broad view in mind

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example - legal aspects
 project: first french « Pay As You Drive » service, for a car insurance
company
 the system was designed and developed
 then, authorization was requested from CNIL (French Personal Data
Protection Agency)
– answer was: « no »
 system had to be re-designed
 think about legal aspects before it's too late

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conclusion - 1/2
 developing software for an IoT/M2M system can be challenging because:
– large diversity of user needs
– sometimes difficult to get real user needs
– different software development paradigms
– integration of technologies from different fields

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conclusion - 2/2
 perhaps more than in other domains:
– spend time with users
– get (really) experienced with involved technologies
– get the overall view
– be agile
– design/use hardware that allows for agility (easy (remote) update)
 but, in any case, have fun!!

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thanks
pascal.bodin@monblocnotes.com
www.monblocnotes.com
@PascalBod06
fr.linkedin.com/in/pascalbodin/

IoT and M2M for Software Developers

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