Can’t receive UDP packets after x seconds

SARA AFF
1

I’m trying to receive UDP packets on my Sodaq Sara R412M AFF.
During connection setup I have some UDP handshaking, which is working fine (both send and receive).
Then the device is idle for a while, waiting for new commands.
If I send a new UDP package towards the device after 10 seconds, it is no longer received on the device (I check with USORF=0,0 but also monitor for UUSORF).
I assume that the socket is no longer active after x seconds because of the UDP protocol specification?

I also tried to implement AT+USOLI=0,4200, but I always get +CME ERROR: Operation not allowed.
I thought maybe it’s because the socket is still open so I also tried to close the socket but also AT+USOLI=1,4200 but the error remains the same. What does it mean?

This is the command list I use:

AT+CFUN=0
AT+URAT=8
AT+UDCONF=1,1
AT+CMEE=2
AT+CGDCONT=1,“IP”,“nb.inetd.gdsp”
AT+CFUN=1
AT+COPS=1,2,“20404”
AT+CSQ
AT+CGATT?
AT+USOCR=17,4200
AT+USOST=0,“10.20.30.40”,6200,13,“49276D20636F6E6E6563746564”
AT+USORF=0,0
AT+USOLI=0,4200
+CME ERROR: Operation not allowed

AT+GMR
M0.09.00 [Jan 31 2019 18:59:31]

2

The problem is located in the power saving mode settings of the modem.
After turning it off, it’s possible to receive UDP packets any time:

AT+CEDRXS=0,5

Both DRX and PSM settings are related to power savings.

1 Like
3

Thanks for sharing your solution.

In our latest version of the library we also noticed that PSM and eDRX are enabled by default.
In the latest library we turn off PSM and eDRX be default.

Best regards,
Jan