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IoT and M2M for Software Developers

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Slide deck of a one-day presentation for software developers who would like to know more about IoT and M2M.

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IoT and M2M for Software Developers

  1. 1. IoT and M2M for software developers Pascal BODIN 31-Jan-2015 V20150131https://creativecommons.org/
  2. 2. 2/147 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
  3. 3. 3/147 0. foreword part 0.1 who I am part 0.2 why we won't speak about software only
  4. 4. 4/147 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...)
  5. 5. 5/147 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
  6. 6. 6/147 1. some use cases
  7. 7. 7/147 container tracking
  8. 8. 8/147 taxi dispatch Taxis waiting at taxi stand Cruising taxi Central dispatch office Sector 1 Sector 2 Customer
  9. 9. 9/147 environmental monitoring
  10. 10. 10/147 logistics
  11. 11. 11/147 home automation
  12. 12. 12/147 smart grid
  13. 13. 13/147 remote monitoring of copy machines
  14. 14. 14/147 2. some definitions
  15. 15. 15/147 let's share same vocabulary central sideremote side machine vehicle etc. (embedded) device gateway central system user administrator enterprise information system
  16. 16. 16/147 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]
  17. 17. 17/147 IoT/M2M definitions? - 2/3  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]
  18. 18. 18/147 IoT/M2M definitions? - 3/3  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!
  19. 19. 19/147 3. overall architecture
  20. 20. 20/147 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
  21. 21. 21/147 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.
  22. 22. 22/147 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
  23. 23. 23/147 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
  24. 24. 24/147 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
  25. 25. 25/147 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
  26. 26. 26/147 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!
  27. 27. 27/147 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
  28. 28. 28/147 architecture communication module microcontroller (memory) (embedded) device interfaces location module user interface communication network
  29. 29. 29/147 example microcontroller communication module location module analog inputs digital I/O
  30. 30. 30/147 communication module - 1/2  communication module can be managed as a peripheral of the microcontroller
  31. 31. 31/147 communication module - 2/2  communication module can host application software
  32. 32. 32/147 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
  33. 33. 33/147 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.
  34. 34. 34/147 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
  35. 35. 35/147 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
  36. 36. 36/147 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.
  37. 37. 37/147 interfacing with peripherals - 2/8  general purpose digital input/output (GPIO): – read or set a voltage (high / low)
  38. 38. 38/147 interfacing with peripherals - 3/8  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
  39. 39. 39/147 interfacing with peripherals - 4/8  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
  40. 40. 40/147 interfacing with peripherals - 5/8  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
  41. 41. 41/147 interfacing with peripherals - 6/8  serial bus: I2C (Inter-Integrated Circuit) – two-wire synchronous serial bus – multi-master – short distance – same applications than for SPI
  42. 42. 42/147 interfacing with peripherals - 7/8  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)
  43. 43. 43/147 interfacing with peripherals - 8/8  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)
  44. 44. 44/147 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.
  45. 45. 45/147 what can we do with a microcontroller? - 1/2 taxi driver taxi central dispatch office taxi repeater
  46. 46. 46/147 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.
  47. 47. 47/147 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
  48. 48. 48/147 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)
  49. 49. 49/147 connectivity communication module microcontroller (memory)interfaces location system user interface communication network command + data interface
  50. 50. 50/147 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)
  51. 51. 51/147 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.
  52. 52. 52/147 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
  53. 53. 53/147 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
  54. 54. 54/147 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
  55. 55. 55/147 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
  56. 56. 56/147 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 €
  57. 57. 57/147 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
  58. 58. 58/147 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
  59. 59. 59/147 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
  60. 60. 60/147 positioning - 3/5 communication module microcontroller (memory)interfaces location system user interface communication network command + data interface
  61. 61. 61/147 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
  62. 62. 62/147 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?
  63. 63. 63/147 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
  64. 64. 64/147 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
  65. 65. 65/147 execution environment Morpheus3 VxWorks RTX OS RTOS specific runtime interrupt handlers + background task ... ... ... Esterel Lustre bare metal Ada
  66. 66. 66/147 bare metal - 1/9  let's look more closely at a microcontroller architecture
  67. 67. 67/147 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
  68. 68. 68/147 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
  69. 69. 69/147 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.
  70. 70. 70/147 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
  71. 71. 71/147 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
  72. 72. 72/147 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
  73. 73. 73/147 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
  74. 74. 74/147 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:
  75. 75. 75/147 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.
  76. 76. 76/147 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
  77. 77. 77/147 functional view communication network communication server application software data persistence UI (user interface) GIS (Geographic Information System) device management user management
  78. 78. 78/147 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.
  79. 79. 79/147 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.
  80. 80. 80/147 communication server - 2/4  example: – for PMR or unlicensed radio antennas transceivers + modems communication server
  81. 81. 81/147 communication server - 3/4  example: – for 3GPP communication server Internet
  82. 82. 82/147 communication server - 4/4  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.
  83. 83. 83/147 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
  84. 84. 84/147 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
  85. 85. 85/147 Geographic Information Systems - 2/4  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.
  86. 86. 86/147 Geographic Information Systems - 3/4  data: – OpenStreetMap (Open Source)
  87. 87. 87/147 Geographic Information Systems - 4/4  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
  88. 88. 88/147 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
  89. 89. 89/147 central side part 5.1 architectures – functional view view – architectures – communication server – databases – GIS – User Interface part 5.2 platforms part 5.3 developing with platforms
  90. 90. 90/147 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
  91. 91. 91/147 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
  92. 92. 92/147 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
  93. 93. 93/147 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
  94. 94. 94/147 central side part 5.1 architectures – functional view view – architectures – communication server – databases – GIS – User Interface part 5.2 platforms part 5.3 developing with platforms
  95. 95. 95/147 platforms - 1/2  often, two different logical interfaces: – devices – central application
  96. 96. 96/147 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
  97. 97. 97/147 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
  98. 98. 98/147 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
  99. 99. 99/147 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
  100. 100. 100/147 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
  101. 101. 101/147 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
  102. 102. 102/147 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
  103. 103. 103/147 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
  104. 104. 104/147 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
  105. 105. 105/147 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)
  106. 106. 106/147 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
  107. 107. 107/147 MQTT  example of use case
  108. 108. 108/147 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
  109. 109. 109/147 MQTT  MQTT implementations (cont'd): – HiveMQ: – server – interesting list of MQTT client tools – etc.
  110. 110. 110/147 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
  111. 111. 111/147 CoAP  CoAP: – Constrained Application Protocol – current version: June 2014 – designed and maintained by IETF (Internet Engineering Task Force) - RFC7252
  112. 112. 112/147 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
  113. 113. 113/147 CoAP
  114. 114. 114/147 CoAP  CoAP implementations: – Eclipse IoT - Californium project (open source) – core – Scandium project: security – Actinium project: server – tools – connector – a sandbox server is available – other implementations: check Wikipedia
  115. 115. 115/147 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
  116. 116. 116/147 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...
  117. 117. 117/147 other protocols  LWM2M implementations: – Eclipse IoT - Wakaama project (open source) – C client and server – a sandbox server is available
  118. 118. 118/147 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
  119. 119. 119/147 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.
  120. 120. 120/147 open or free hardware/software - 2/3  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.
  121. 121. 121/147 open or free hardware/software - 3/3  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.
  122. 122. 122/147 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
  123. 123. 123/147 ecosystem - 1/4  what we saw: – many different use cases – several different technologies  => ecosystem and value chain are complex
  124. 124. 124/147 ecosystem - 2/4  usually, value chain is depicted like this:
  125. 125. 125/147 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
  126. 126. 126/147 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
  127. 127. 127/147 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
  128. 128. 128/147 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)
  129. 129. 129/147 standards - 2/6  in Europe: ETSI (European Telecommunications Standards Institute) – M2M communications
  130. 130. 130/147 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
  131. 131. 131/147 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
  132. 132. 132/147 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)
  133. 133. 133/147 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
  134. 134. 134/147 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
  135. 135. 135/147 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)
  136. 136. 136/147 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
  137. 137. 137/147 example - user needs - 2/3  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
  138. 138. 138/147 example - user needs - 3/3  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
  139. 139. 139/147 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
  140. 140. 140/147 example - technology - 2/4  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
  141. 141. 141/147 example - technology - 3/4  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
  142. 142. 142/147 example - technology - 4/4  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
  143. 143. 143/147 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
  144. 144. 144/147 conclusion
  145. 145. 145/147 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
  146. 146. 146/147 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!!
  147. 147. 147/147 thanks pascal.bodin@monblocnotes.com www.monblocnotes.com @PascalBod06 fr.linkedin.com/in/pascalbodin/

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