SIMCOM A7600E trouble receiving UDP packages

Question

I'm having trouble receiving UDP packages using a A7600E modem. I am required to send and receive UDP packages over LTE using dedicated IP addresses.

I am able to:

• obtain the dedicated IPv4 the ISP has allocated for us.
• send a package over the internet, The arriving package has the proper sending IP/port
• send and receive TCP packages using the TCP client and server. (but my boss wants me to send UDPs)

There is no firewall at the ISP level, I've checked with another modem.

This is the command sequence I use to send packages. I cannot receive anything over UDP when I send packages to 79.118.XX.XX

ATI
Manufacturer: INCORPORATED
Model: A7600E-LNSE
Revision: A7600M7_V8.18.1
IMEI: 86999XXXXXXXXXX
+GCAP: +CGSM,+FCLASS,+DS

AT+CGMR
+CGMR: A818B03A7600M7

AT+CGATT=1
OK
AT+CGACT=1,1
OK

+CGEV: NW MODIFY 1,4
AT+CGPADDR=1
+CGPADDR: 1,46.97.XX.XX

OK
AT+NETOPEN
OK

+NETOPEN: 0
AT+CIPOPEN=0,"UDP",,,15000
+CIPOPEN: 0,0

AT+CIPSEND=0,10,"77.81.XX.XX",21000
>ewewwe4343
OK

+CIPSEND: 0,10,10
AT+CIPOPEN=1,"UDP",,,21000
+CIPOPEN: 1,0

OK
AT+CIPOPEN?
+CIPOPEN: 0,"UDP","79.118.XX.XX",21000,-1
+CIPOPEN: 1,"UDP","0.0.0.0",0,-1
+CIPOPEN: 2
+CIPOPEN: 3
+CIPOPEN: 4
+CIPOPEN: 5
+CIPOPEN: 6
+CIPOPEN: 7
+CIPOPEN: 8
+CIPOPEN: 9

OK

Thank you for your help

Answer 1

I've emailed the SIMCom official support channel and they acknowledged there's a firmware issue with UDP on A7600 series and they provide me with an update which solved the issue. I'm not sure it will be a good think to post the link since it's a beta firmware and I hope they'll make it available soon on their official channels.

Thanks everybody.