Co CoAP an and d MQTT TT Antonio Lin Colina, Zolertia - - PowerPoint PPT Presentation

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Co CoAP an and d MQTT TT Antonio Lin Colina, Zolertia - - PowerPoint PPT Presentation

Sep 14, 2022 659 likes •1.09k views

Co CoAP an and d MQTT TT Antonio Lin Colina, Zolertia http://electronicdesign.com/iot/mqtt-and-coap-underlying-protocols-iot 03 03-coap coap UDP- reliable (confirmable), SMS supported CoRE Link-format (GET /.well known/core

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Co CoAP an and d MQTT TT

Antonio Liñán Colina, Zolertia

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http://electronicdesign.com/iot/mqtt-and-coap-underlying-protocols-iot

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03 03-coap coap

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https://tools.ietf.org/html/rfc7252 http://coap.technology/

  • UDP-reliable (confirmable), SMS supported
  • CoRE Link-format (GET /.well known/core)
  • Client/Server
  • IANA Registered (error codes, content format)
  • Resource Discovery and asynchronous subscription
  • Four-bytes compact header
  • Multicast and one-to-one supported
  • HTTP verbs GET, PUT, POST, DELETE
  • HTTP-like header (Options)
  • URI (Uniform Resource Identifier)
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http://www.slideshare.net/zdshelby/coap-tutorial

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CoAP P UR URI

coap://[aaaa::c30c:0:0:1234]:5683/actuators/leds?color=b

Host Port Path Query

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http://www.slideshare.net/paolopat/mqtt-iot-protocols-comparison

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apps/er-coap apps/rest-engine

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apps/er-coap apps/rest-engine

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apps/er-coap apps/rest-engine

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examples/zolertia/tutorial/03-coap/resources/res-adxl345.c Resource declaration Resource implementation URI Query Function to invoke whenever there’s a GET request The CoAP Accept option can be used to indicate which Content- Format is acceptable to the client.

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examples/zolertia/tutorial/03-coap/resources/er-example-server.c Resource activation Importing the Resource

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examples/zolertia/tutorial/03-coap/resources/Makefile Search resources to include in the “resources” directory REST engine and CoAP libraries

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https://addons.mozilla.org/en-US/firefox/addon/copper-270430/ http://people.inf.ethz.ch/mkovatsc/copper.php

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examples/zolertia/tutorial/02-ipv6/03-client-and-server er er-examp ample-se server ver CoAP server in Contiki OS Border der Router er IPv6/6LoWPAN Copper per CoAP P user-ag agen ent On Firefox browse the CoAP Server, discover and learn its resources

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apps/er-coap apps/rest-engine

TIP: enable the DEBUG to 1 to print more information about the processes taking place inside the CoAP and REST libraries (all .c files inside!)

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Pong! – check the CoAP server is online

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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Discover – learn the Resources the CoAP server has

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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Hover over the resources to learn its attributes

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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POST/PUT – change the LEDs state (on or off)

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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GET – read the ADXL345 with JSON format (application/json)

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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OBSERVE – get notifications about an event (press the user button)

examples/zolertia/tutorial/03-coap/resources/er-example-server.c

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04 04-mqtt mqtt

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http://mqtt.org

  • On top of TCP/IP
  • Publish/Subscribe messaging pattern
  • Message Broker distributes topics to clients
  • Topics are UTF-8 string-based with hierarchical structure
  • No direct connection between clients
  • Quality of Service
  • Retain-Flag: new subscribed clients will received last value
  • Last Will: notify other clients when disconnected ungracefully
  • KeepAlive: ping request messages to the bróker
  • Clients have to know beforehand the structure of the data published to a

topic

  • MQTT is data-agnostic
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CONNECT

Waits for a connection to be established with the server

DISCONNECT

Waits for the MQTT client to finish any pending task and closes the TCP session

SUBSCRIBE

Request the server to subscribe the client to one or more topics

UNSUBSCRIBE

Request the server to subscribe the client to one or more topics

PUBLISH

Updates a topic with data

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http://www.hivemq.com/blog/how-to-get-started-with-mqtt

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http://www.slideshare.net/paolopat/mqtt-iot-protocols-comparison

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http://www.hivemq.com/blog/mqtt-essentials-part-5-mqtt-topics-best-practices

Topics starting with $ are special These are reserved for the broker statistics

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apps/mqtt Required to be included in the process using MQTT

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apps/mqtt To start the MQTT client this function should be called first The max_segment_size is the TCP chunk of data to be sent (default is 32 bytes) The client_id is a string identifying the client

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apps/mqtt The keep_alive value is used by a timer waiting a PINGRES from the broken, if expired and no response is obtained, it triggers a disconnection

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apps/mqtt Message ID (mid) is zero for QoS=0

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apps/mqtt

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apps/mqtt

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mqtt tt-de demo mo The MQTT client publishing to the topic “zolertia/evt/status” and subscribed to “zolertia/cmd/leds” Border der Router er IPv6/6LoWPAN mqtt_c tt_cli lient nt.p .py Paho MQTT client Subscribed to the “zolertia/evt/status” topic, used to check the example examples/zolertia/tutorial/04-mqtt MQTT brók óker test.mosquitto.org

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examples/zolertia/tutorial/04-mqtt

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examples/zolertia/tutorial/04-mqtt

static void mqtt_event(struct mqtt_connection *m, mqtt_event_t event, void *data) { switch(event) { case MQTT_EVENT_CONNECTED: { printf("APP - Application has a MQTT connection\n"); state = STATE_CONNECTED; break; } case MQTT_EVENT_DISCONNECTED: { printf("APP - MQTT Disconnect. Reason %u\n", *((mqtt_event_t *)data)); state = STATE_DISCONNECTED; process_poll(&mqtt_demo_process); break; } case MQTT_EVENT_PUBLISH: { pub_handler(msg_ptr->topic, strlen(msg_ptr->topic), msg_ptr->payload_chunk, msg_ptr->payload_length); break; } case MQTT_EVENT_SUBACK: { printf("APP - Application is subscribed to topic successfully\n"); break; } case MQTT_EVENT_UNSUBACK: { printf("APP - Application is unsubscribed to topic successfully\n"); break; } case MQTT_EVENT_PUBACK: { printf("APP - Publishing complete.\n"); break; } }

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examples/zolertia/tutorial/04-mqtt STATE_I TE_INIT NIT: mqtt_register(…) STATE_R TE_REG EGIS ISTER TERED: ED: mqtt_connect(…) STATE_C TE_CONNEC NECTING TING: : ctimer checking(…) STATE_C TE_CONNEC NECTED TED: : mqtt_subscribe(…) STATE_PUBLISH TE_PUBLISHING ING: : etimer_set(publish interval) DISCO CONNEC NECTED TED: : mqtt_disconnect(…)

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examples/zolertia/tutorial/04-mqtt Set default configuration values Create topic/subscription/id strings (STATE_INIT) Polls the state machine as described before

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apps/mqtt/mqtt.c

TIP: enable the DEBUG to 1 to print more information about the processes taking place inside the MQTT library

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examples/zolertia/tutorial/04-mqtt MQTT demo client running on the Z1 mote Paho MQTT client in Python subscribed Mosquitto publishing to turn a LED on

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An Antonio

  • nio Li

Liñán án Colina lina

Twitter: @4Li6NaN LinkedIn: Antonio Liñan Colina github.com/alignan hackster.io/alinan

alinan@zolertia.com antonio.lignan@gmail.com