SES CMAKE ERROR

[dhandzic]

I have installed the latest SDK 1.3.0 using the Toolchain Manager.

I would now like to open nRF Connect SDK Projekt and get the follwoing error:

I have added the CXX environment variable, but it did not help

[Didrik Rokhaug]

If you log in to nRF Cloud, and select "SIM cards" in the menu on the left, you should be able to see how much data is left on your iBasis SIM card, along with an option to buy more (note that this will replace any data you have left, not add to it). A TLS handshake can take quite a lot of data, so if the device has been running in a reset-loop doing a TLS handshake each time, the data can be used quite quickly.

[dhandzic]

Yes, indeed it seems the 10 MB on the iBasis SIM have already been used up when I check the SIM status on nRF Cloud. That is a surprise. We plan to use LwM2M for our application (remote door control) which normally uses very little data, but if TLS handshaking can use a lot of data that might have a big impact on the dataplan we are planning to use. Is there any way to avoid this? Can the use of DTLS and CID reduce that? Is this implemented in Nordics LwM2M client?

[Didrik Rokhaug]

LwM2M uses UDP, not TCP so you would use a DTLS not TLS. Not that the difference is very significant in this case.

The modem (where the DTLS stack resides) makes no assumptions on the validity of the DTLS session, and will try to continue the old session unless the server rejects it.

So, if you can control the disconnect timeout on the server, you can increase it to reduce the number of DTLS handshakes necessary. Another way would be to keep the connection alive from the client side, but that would mean sending data more often which also means increased power usage.

The data usage might also depend on the key types used. I just checked an IP trace I have from some previous LwM2M experimentation I did using DTLS with PSKs, and the handshake ended up with a total of 766 bytes, counting data in both directions. I expect that number to be bigger if you are using a public/private key pair, as those keys can be large themselves (often ~1.5KB).

[dhandzic]

Hi Didrik,

I have changed to the Telia eSIM and the asset tracker app is working again. RSRP is a bit strange showing values from -120dBm to -133dBm and nRF9160 datasheets says -108 dBm sensitivity for low bands. This means signal strength is far below sensitivity level??

[dhandzic]

Hi Didrik,

I have now switched to the LwM2M_client from the 1.3.1 SDK and when using Target>Download zephyr/merged.hex I am getting a strange error at the end of the build process: