Serial LTE Modem - Release Assistance

[Michal Mühlpachr]

How can we use RAI in SLM please ?

I was not able to find corresponding commands alike in Modem Shell:

sock rai --rai_enable
sock rai -i 0 --rai_last

[Albrecht Markus Schellenberger]

Hello Michal,

you can use the Release assistance indication %RAI AT command in SLM.

Regards,

Markus

[Michal Mühlpachr]

With %RAI set I need then to notice modem about last TX datagram or wait for one RX datagram.

I can find AT command in SLM whit implementation alike sock_rai_option_set and sock_rai
https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/modem_shell/src/sock/sock.c#L1192

It is stated at infocenter.nordicsemi.com/.../rai.html

"In addition to using the %RAI command, the application must tell when the data connection is not needed anymore through the application domain data socket interface."

How can I do that in SLM please ?

Regards, Michal

[Albrecht Markus Schellenberger]

Hello Michal,

I’m not sure if the Serial LTE modem application has native support for this. I have to check with our developers!

Regards,

Markus

[Albrecht Markus Schellenberger]

Hello again Michal,

this is not supported by the Serial LTE modem application yet, but the functionality was recently added to the master branch.

The test sequence will look like below:

AT%RAI=1
AT+CSCON=1
<attach>
at#xsocket=1,2,0
at#xsocketopt=1,52
at#xsendto=<url>,<port>[,<data>]

52 is one uplink packet and one downlink packet, then release RRC connection. The server listed above is an ECHO server, we open a UDP packet, send something to it, get the echoed packet. The +CSCON will report when RRC is released.

Our developers have verified this working in a few NB-IoT networks.

You can also check the pull request, which comes with a nice documentation for the socket service.

I hope this answers your question!

Regards,

Markus