Implement simple block transfer CoAP in thread

RE: Implement simple block transfer CoAP in thread

gc0rreiab — Mon, 15 Dec 2025 18:55:58 GMT

The Zephyr CoAP library also implements block-wise transfers.

Could you point me to the part of the Zephyr CoAP library that implements block-wise transfer, or provide a reference on how to get started? I would like to transmit payloads of up to 2500 bytes to a CoAP server over OpenThread.

RE: Implement simple block transfer CoAP in thread

Jørgen Holmefjord — Tue, 08 Jun 2021 13:13:46 GMT

Unfortunately, we do not have any other examples that show how to transfer larger files over CoAP in Thread network.

There was also recently added support for CoAP block-wise transfers in the OpenThread CoAP API, but this would require you to rebuild the libraries for the latest OpenThread version, and migrate all function changes in the SDK to work with this new version. There is also no examples that shows how to use this API in nRF5 SDK.

Another option would be to switch to using nRF Connect SDK. The Zephyr COAP library also implements block-wise transfers.

Best regards,
Jørgen

RE: Implement simple block transfer CoAP in thread

mj_zen — Tue, 08 Jun 2021 12:58:59 GMT

I have question with request to Thread Secure DFU protocol. Is there any simpler example to implement that solution?

RE: Implement simple block transfer CoAP in thread

Jørgen Holmefjord — Tue, 08 Jun 2021 11:59:16 GMT

Hi,

I will recommend you to have a look at our Thread Secure DFU protocol solution. This uses CoAP blocks to transfer the new firmware from the server to the client. In unicast mode, the client will send GET request messages to the server to request each block.

Best regards,
Jørgen