CoAP

Example 1: Non confirmable request and non confirmable response

Client  Server
    |      |
    |      |
    +----->|     Header: GET (T=NON, Code=0.01, MID=0x7d40)
    | GET  |      Token: 0x75
    |      |   Uri-Path: "temperature"
    |      |
    |      |
    |<-----+     Header: 2.05 Content (T=NON, Code=2.05, MID=0xad7d)
    | 2.05 |      Token: 0x75
    |      |    Payload: "22.3 C"
    |      |

    Figure 22: Non-confirmable Request; Non-confirmable Response

Name: not_safe

Request_handler:

• Message type -> Non Confirmable
• Message code -> GET (0.1)
• Message ID -> Any
• Uri-Path -> "temperature"
• Token -> VALUE_A

Response:

• Message type -> Non Confirmable
• Message code -> Content (2.05)
• Token -> VALUE_A
• Payload -> MeshLocalID

Test with libcoap:

coap-client -m get -N coap://[$ot ipaddr mleid]/temperature -v 9

Example 2: Confirmable request and non confirmable piggyback response

Client              Server       Client              Server
    |                  |             |                  |
    |   CON [0xbc90]   |             |   CON [0xbc91]   |
    | GET /temperature |             | GET /temperature |
    |   (Token 0x71)   |             |   (Token 0x72)   |
    +----------------->|             +----------------->|
    |                  |             |                  |
    |   ACK [0xbc90]   |             |   ACK [0xbc91]   |
    |   2.05 Content   |             |  4.04 Not Found  |
    |   (Token 0x71)   |             |   (Token 0x72)   |
    |     "22.5 C"     |             |   "Not found"    |
    |<-----------------+             |<-----------------+
    |                  |             |                  |

    Figure 4: Two GET Requests with Piggybacked Responses

Name: dodgy_pig

Request_handler:

• Message type -> Confirmable
• Message code -> GET (0.1)
• Message ID -> VALUE_MSG_ID
• Uri-Path -> "luminosity"
• Token -> VALUE_TOKEN

Response:

• Message type -> Acknowledgment
• Message code -> Content (2.05)
• Message ID -> VALUE_MSG_ID
• Token -> VALUE_TOKEN
• Payload -> MeshLocalID

Test with libcoap:

coap-client -m get coap://[$ot ipaddr mleid]/luminosity -v 9

Example 3: Confirmable request and confirmable separate response

Name: divorce_confirmation

Request_handler(confirmable):

• Message type -> Confirmable
• Message code -> GET (0.1)
• Message ID -> VALUE_MSG_ID_A
• Uri-Path -> "luminosity"
• Token -> VALUE_TOKEN_A

Response(ack):

• Message type -> Acknowledgment
• Message code -> Empty (0.00)
• Message ID -> VALUE_MSG_ID_A

Response(confirmable):

• Message type -> Confirmable
• Message code -> Content (2.05)
• Message ID -> VALUE_MSG_ID_B
• Token -> VALUE_TOKEN_A
• Payload -> MeshLocalID

Request_handler(ack):

• Message type -> Aknowledgment
• Message code -> Empty (0.00)
• Message ID -> VALUE_MSG_ID_B

Test with libcoap:

coap-client -m get coap://[$ot ipaddr mleid]/air_quality -v 9

Normal scenario

Client  Server
    |      |
    |      |
    +----->|     Header: GET (T=CON, Code=0.01, MID=0x7d38)
    | GET  |      Token: 0x53
    |      |   Uri-Path: "temperature"
    |      |
    |      |
    |<- - -+     Header: (T=ACK, Code=0.00, MID=0x7d38)
    |      |
    |      |
    |<-----+     Header: 2.05 Content (T=CON, Code=2.05, MID=0xad7b)
    | 2.05 |      Token: 0x53
    |      |    Payload: "22.3 C"
    |      |
    |      |
    +- - ->|     Header: (T=ACK, Code=0.00, MID=0xad7b)
    |      |

            Figure 20: Confirmable Request; Separate Response

Error

Client  Server
    |      |
    |      |
    +----->|     Header: GET (T=CON, Code=0.01, MID=0x7d39)
    | GET  |      Token: 0x64
    |      |   Uri-Path: "temperature"
CRASH    |
    |      |
    |<- - -+     Header: (T=ACK, Code=0.00, MID=0x7d39)
    |      |
    |      |
    |<-----+     Header: 2.05 Content (T=CON, Code=2.05, MID=0xad7c)
    | 2.05 |      Token: 0x64
    |      |    Payload: "22.3 C"
    |      |
    |      |
    +- - ->|     Header: (T=RST, Code=0.00, MID=0xad7c)
    |      |

    Figure 21: Confirmable Request; Separate Response (Unexpected)

Testing

Requirements

In order to test this examples you should:

1. Install the nrf-5x SDK (tested in version 1.4.0)
2. Pull this repository to <name_of_folder> out of the SDK path
3. Copy to samples/openthread/

   $ cp -r <name_of_folder> ${ZEPHYR_BASE}/../nrf/samples/openthread/

4. Open terminal in the SDK folder

   $ cd ${ZEPHYR_BASE}/../nrf/samples/openthread/<name_of_folder>

Build

• For nrf52840dk

  $ west build --b nrf52840dk_nrf52840

• For nrf52833dk

  $ west build --b nrf52833dk_nrf52833

Flash

There are 2 different devices:

1. Open JLinkExe
   • nrf52833dk binary

     $ sudo JLinkExe -device NRF52833_XXAA -if swd -speed 1000

   • nrf52833dk binary

     $ sudo JLinkExe -device NRF52840_XXAA -if swd -speed 1000

2. Connect to device

   $ connect

3. Erase previous flash content

   $ erase

4. Flash .hex file

   $ loadfile bin/<name_of_file>

Debug

Devices:

• /dev/ttyACM0 -> nrf52840dk
• /dev/ttyACM1 -> nrf52840 dongle (ot-br)
• /dev/ttyACM2 -> nrf52833dk

Connect to ot-br:

$ sudo ot-ctl

Connect to other devices:

$ screen <device_name> 115200