receive UDP on nRF9160-dk SLM application

[AndMar8]

Hi,

I want to receive UPD message on my nRF9160-DK.

I can send UDP messages from my Nordic device to a server and from that messages I get the public IP address of my module. But when I try to receive messages, I don't receive anything.  

I use the serial LTE modem application.

I see the following links to send messages:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/serial_lte_modem/doc/TCPIP_AT_commands.html#udp-receive-data-xrecvfrom

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/serial_lte_modem/doc/slm_description.html

First try:

AT#XSOCKET=1,2,0

#XSOCKET: 1, 2, 0, 17

OK

AT#XSENDTO="x.x.x.x",20080,1,"Test UDP"

#XSENDTO: 8

OK

AT#XSOCKET=0

#XSOCKET: 0, closed

OK

AT#XSOCKET=1,2,1

#XSOCKET: 1, 2, 1, 17

OK

AT#XBIND=3442

OK

AT#XRECVFROM

and after this I get: "Error: 'AT#XRECVFROM' timed out"  and I cannot send AT command to LTE Link Monitor.

-------------------------------------------------------------------------

Second try:

AT#XSOCKET=1,2,0

#XSOCKET: 1, 2, 0, 17

OK

AT#XSENDTO="x.x.x.x",20080,1,"Test UDP"

#XSENDTO: 8

OK

AT#XSOCKET=0

#XSOCKET: 0, closed

OK

AT#XSOCKET=1,2,1

#XSOCKET: 1, 2, 1, 17

OK

AT#UDPRECVFROM="x.x.x.x",3442

+CME: 0

Here I don't know how to solve this error.


-------------------------------------------------------------------------

Third try:

I set the UDP proxy to use the command AT#XUDPSVR;
So in "Configure nRF Connect SDK Project" I select "Stateful connection-oriented UDP client/server <SLM_UDP_PROXY>"

AT#XUDPCLI=1,"x.x.x.x",20080

#XUDPCLI: 1 connected

OK

%CESQ: 32,1,19,2

%CESQ: 29,1,24,3

AT#XUDPSEND=1,"Test UDP"

#XUDPSEND: 8

OK

AT#XUDPCLI=0

#XUDPCLI: disconnected

OK

AT#XUDPSVR=1,3442 or AT#XUDPSVR=2,3442

#XUDPSVR: 1 started

OK

Here it seems to work but I don't receive anything and retrying I get sometimes: "Error: 'AT#XUDPSVR=1,3442 ' timed out"

I try using the IP that I get in the receiving messages and also with the IP that I get with the command "AT+CGDCONT?"

I try also using the example script "client_udp.py" but nothing.

I try many times with all possible combinations.

What can I do? The nRF9160-DK receives messages but doesn't print them on the LTE Link Monitor or I'm using wrong AT command? Is there an error in the client code? Is the IP that I use the error? Is it possible that my server doesn't know how to reach my APN even if I specify the correct public IP address?

Please, help me to receive a simple "hello".
Thank you in advance.

Best regards

[Didrik Rokhaug]

Hi,

You should not close the socket after sending data, for so to open a new socket that you listen on.

Instead, you should listen on the same socket that you sent data from.

Also, be aware that due to Christmas vacations, response times might be slower than normal.

Best regards,

Didrik

[AndMar8]

Hi,
Thanks for the answer.
I tried without closing the socket but the recvfrom returns always this error: "Error: 'AT#XRECVFROM ' timed out" and always from here I can't send AT command through the LTE Link Monitor.
In the following I put the command used:

First try:

AT#XSOCKET=1,2,1
#XSOCKET: 1, 2, 1, 17
OK

AT#XBIND=3442
OK

AT#XSENDTO="x.x.x.x",20080,1,"Test UDP"
#XSENDTO: 8
OK

AT#XRECVFROM (here stops)

-----------------------------------------------------------

Second try:

AT#XSOCKET=1,2,0
#XSOCKET: 1, 2, 0, 17
OK

AT#XSENDTO="x.x.x.x",20080,1,"Test UDP"
#XSENDTO: 8
OK

AT#XRECVFROM (here stops)

I have to change something in the project file?

I closed socket in previous tries because I thought that I have to set the socket in client mode (AT#XSOCKET=1,2,0) to send messages and in server mode (AT#XSOCKET=1,2,1) to receive messages.

Best regards

 

[AndMar8]

Hi,

1. I believe that the messages are sent by my device because when I send messages from nRF9160 they appear on the node-red debug messages window (as in the screeshot). However to be sure is there an at command to get the IP address of my nRF9160?

2. Debug:

I didn't find CONFIG_SLM_LOG_LEVEL=y so I guess you mean CONFIG_SLM_LOG_LEVEL_DBG=y (I hope it's correct).

For the debugging I also set in the prj.config file:

CONFIG_USE_SEGGER_RTT=n
CONFIG_RTT_CONSOLE=n
CONFIG_UART_CONSOLE=y
CONFIG_LOG_BACKEND_RTT=n
CONFIG_LOG_BACKEND_UART=y

I attached the zip with modem trace bin, terminal of Termite, logfile of LTE Link Monitor and the prj.config file

nRF9160 log.rar

[Achim Kraus]

Usually, neither the local ip-address your nRF9160 nor the local port you use will be visible at the server. The mobile provider mostly use a NAT, which exchanges that address and port. And because of that NAT, you must respond "in time". I would try to start with less than 30s. 

[Didrik Rokhaug]

AndMar8 said:

I didn't find CONFIG_SLM_LOG_LEVEL=y so I guess you mean CONFIG_SLM_LOG_LEVEL_DBG=y (I hope it's correct).

 Yes, sorry. That was a typo on my part.

I also forgot to mention that you have to comment out the CONFIG_SLM_LOG_LEVEL_INF=y line (or replace it with *_DBG=y).

I have also done some more tests myself, and it doesn't seem like the recvfrom call actually gets registered in the modem trace unless it returns some data.

So the 2nd point in my last comment doesn't seem to be an actual problem, just another indication that the device never receives the response.

 

AndMar8 said:

is there an at command to get the IP address of my nRF9160?

 AT+CGDCONT?

But, it is worth noting what Achim Kraus says about NAT.

[Didrik Rokhaug]

Hi AndMar8,

Could you try the following sequence of commands (with the same server and port)?

AT+CEREG=5
AT+CSCON=1
AT+CFUN=1
// Wait for the nRF9160 to be connected (CEREG 1 or 5)
AT#XSOCKET=1,2,0
AT#XSENDTO="84.215.43.232",56227,1,"<some text here>"
AT#XRECVFROM

You should then end up with a log similar to this (if you have enabled debug logging):

Fullscreen slm_udp_working.txt Download

*** Booting Zephyr OS build v2.4.0-ncs1  ***
Ready
[00:00:00.231,994] <inf> app: Serial LTE Modem
[00:00:00.232,177] <dbg> at_host: TX
52 65 61 64 79 0d 0a                             |Ready..          
[00:00:00.232,177] <dbg> at_host.slm_at_host_init: at_host init done
at+cereg=5
OK
[00:00:06.317,932] <dbg> at_host: RX
61 74 2b 63 65 72 65 67  3d 35                   |at+cereg =5      
[00:00:06.318,450] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:06.328,948] <dbg> at_host: TX
[00:00:06.329,010] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
at+cscon=1
OK
[00:00:09.456,085] <dbg> at_host: RX
61 74 2b 63 73 63 6f 6e  3d 31                   |at+cscon =1      
[00:00:09.456,604] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:09.466,735] <dbg> at_host: TX
[00:00:09.466,796] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
at+cfun=1
OK
[00:00:12.772,094] <dbg> at_host: RX
61 74 2b 63 66 75 6e 3d  31                      |at+cfun= 1       
[00:00:12.772,613] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:12.844,238] <dbg> at_host: TX
[00:00:12.844,299] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
+CEREG: 2,"76C1","014A3901",7,0,0,"11100000","11100000"
+CSCON: 1
[00:00:14.167,694] <dbg> at_host: TX
2b 43 45 52 45 47 3a 20  32 2c 22 37 36 43 31 22 |+CEREG:  2,"76C1"
2c 22 30 31 34 41 33 39  30 31 22 2c 37 2c 30 2c |,"014A39 01",7,0,
30 2c 22 31 31 31 30 30  30 30 30 22 2c 22 31 31 |0,"11100 000","11
31 30 30 30 30 30 22 0d  0a                      |100000". .       
[00:00:14.195,556] <dbg> at_host: TX
2b 43 53 43 4f 4e 3a 20  31 0d 0a                |+CSCON:  1..     
+CEREG: 5,"76C1","014A3901",7,,,"00000010","00000110"
[00:00:16.082,397] <dbg> at_host: TX
2b 43 45 52 45 47 3a 20  35 2c 22 37 36 43 31 22 |+CEREG:  5,"76C1"
2c 22 30 31 34 41 33 39  30 31 22 2c 37 2c 2c 2c |,"014A39 01",7,,,
22 30 30 30 30 30 30 31  30 22 2c 22 30 30 30 30 |"0000001 0","0000
30 31 31 30 22 0d 0a                             |0110"..          
at+cgdcont?
+CGDCONT: 0,"IP","ibasis.iot","10.160.177.45",0,0
OK
[00:00:18.583,740] <dbg> at_host: RX
61 74 2b 63 67 64 63 6f  6e 74 3f                |at+cgdco nt?     
[00:00:18.584,259] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:18.595,428] <dbg> at_host: TX
2b 43 47 44 43 4f 4e 54  3a 20 30 2c 22 49 50 22 |+CGDCONT : 0,"IP"
2c 22 69 62 61 73 69 73  2e 69 6f 74 22 2c 22 31 |,"ibasis .iot","1
30 2e 31 36 30 2e 31 37  37 2e 34 35 22 2c 30 2c |0.160.17 7.45",0,
30 0d 0a                                         |0..              
[00:00:18.599,945] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
at#xsocket=1,2,0
#XSOCKET: 1, 2, 0, 17
OK
[00:00:24.831,848] <dbg> at_host: RX
61 74 23 78 73 6f 63 6b  65 74 3d 31 2c 32 2c 30 |at#xsock et=1,2,0
[00:00:24.832,366] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:24.842,163] <dbg> at_host: TX
23 58 53 4f 43 4b 45 54  3a 20 31 2c 20 32 2c 20 |#XSOCKET : 1, 2, 
30 2c 20 31 37 0d 0a                             |0, 17..          
[00:00:24.842,163] <dbg> tcpip.do_socket_open: Socket opened
[00:00:24.844,238] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
+CSCON: 0
[00:00:27.609,008] <dbg> at_host: TX
2b 43 53 43 4f 4e 3a 20  30 0d 0a                |+CSCON:  0..     
at#xsendto="84.215.43.232",56227,1,"didrik port test"
#XSENDTO: 16
OK
+CSCON: 1
[00:00:30.552,490] <dbg> at_host: RX
61 74 23 78 73 65 6e 64  74 6f 3d 22 38 34 2e 32 |at#xsend to="84.2
31 35 2e 34 33 2e 32 33  32 22 2c 35 36 32 32 37 |15.43.23 2",56227
2c 31 2c 22 64 69 64 72  69 6b 20 70 6f 72 74 20 |,1,"didr ik port 
74 65 73 74 22                                   |test"            
[00:00:30.552,825] <dbg> tcpip.parse_host_by_ipv4: IPv4 Address 84.215.43.232
[00:00:30.552,856] <dbg> tcpip.do_udp_init: UDP initialized
[00:00:30.553,009] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:30.561,676] <dbg> at_host: TX
23 58 53 45 4e 44 54 4f  3a 20 31 36 0d 0a       |#XSENDTO : 16..  
[00:00:30.561,706] <dbg> tcpip.do_sendto: UDP sent
[00:00:30.580,383] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
[00:00:30.665,832] <dbg> at_host: TX
2b 43 53 43 4f 4e 3a 20  31 0d 0a                |+CSCON:  1..     
at#xrecvfrom
didrik port test
#XRECVFROM: 1, 16
OK
[00:00:40.058,105] <dbg> at_host: RX
61 74 23 78 72 65 63 76  66 72 6f 6d             |at#xrecv from    
[00:00:40.058,410] <dbg> at_host: TX
64 69 64 72 69 6b 20 70  6f 72 74 20 74 65 73 74 |didrik p ort test
[00:00:40.058,624] <dbg> at_host.uart_callback: RX_DISABLED
[00:00:40.059,875] <dbg> at_host: TX
0d 0a 23 58 52 45 43 56  46 52 4f 4d 3a 20 31 2c |..#XRECV FROM: 1,
20 31 36 0d 0a                                   | 16..            
[00:00:40.059,875] <dbg> tcpip.do_recvfrom: UDP received
[00:00:40.061,798] <dbg> at_host: TX
4f 4b 0d 0a                                      |OK..             
+CSCON: 0
[00:00:42.356,109] <dbg> at_host: TX
2b 43 53 43 4f 4e 3a 20  30 0d 0a                |+CSCON:  0..     

As you can see from the log, I have verified that this server works, and I am able to communicate with it with my nRF9160DK and iBasis SIM card.

I also have some logging running on the server, so it I can confirm that it receives the packet and sends a response.

And, as always, if you could share the log and modem trace afterwards, that would be great.

[AndMar8]

Hi,

Unluckily I had already tried with the IP that I got with AT+CGDCONT? and I have the same results.

Just to let you know, I had done other test with different types of protocol of communication:

MQTT works fine: I connect the nRF9160 to a topic of a block of NODE-RED and i can receive and send messages.

TCP works fine only if I use the nRF9160 as client which has to connect to NODE-RED (as server). In this case I can send and receive message.
But if I use NODE-RED as client which has to connect to nRF9160 (as server), when I use the commands AT#XLISTEN and AT#XACCEPT, nothing happens.
I try both with the IP address of the screenshot (151.x.x.x) and with the IP address that I get with the command AT+CGDCONT? (10.x.x.x).

I think it could be for the same reason of UDP RECVFROM.

However I think that the correct IP address is 151.x.x.x and not 10.x.x.x.

I found out also that in the LTE Link monitor if I got in the Log window:

 Error: 'at#xrecvfrom' timed out 

It doesn't block the code as I thought but it's still worked. I got the same error with TCP protocol and AT#XRECV but I can receive messages, too. So fine :).

What kind of application do you use to send udp messages to nRF9160-dk? So I'll try with it, instead of NODE-RED. Probably has problem with UDP protocol.

Now I try the commands you send me! Thank you very much!