RE: NRF5 SDK 14.2 IoT MQTT, app_scheduler, and TLS

Jørgen Holmefjord — Fri, 23 Feb 2018 15:16:14 GMT

The issue with mbedtls is that it contains an internal loop that will block scheduled RX events. The SDK is written to be modular, making it easy to change the backend of the modules. There is a nrf_tls abstraction layer that can be found in components/drivers_ext/tls folder, that you can use for implementing another TLS backend. Please have a look at how this is done inside the mbedtls directory.

RE: NRF5 SDK 14.2 IoT MQTT and TLS Architecture

frazieje — Tue, 20 Feb 2018 20:45:57 GMT

Since makeing this request I upgraded my project from the old IoT SDK and prototype softdevice to use NRF5 SDK 14.2.x and the S132 5.0 softdevice. I also reworked my application to use the app_scheduler library for scheduling tasks during interrupts. This worked very well and brought some nice improvements in my application design, as well as improved the overall stability / consistency of my application.

My questions as listed above still remain, but I did do some more digging, and for the most part it looks like I could bring in a different TLS implementation (wolfSSL?) to the Nordic MQTT client library without too much trouble, although I would still like some opinions on that.