WP8548 modem freezes

IoT Modules WP Series
1

Hello.
We are creating a new product based on WP8548-G, but we are faced with the following problem.
When transferring data between the device (WP8548) and the server through a modem, after receiving the first packet from the server, there is a delay after the data has been written to the socket and the moment it was received by the server.
It may be a few seconds. When transmitting subsequent data, this is not observed (delays correspond to network bandwidth ). If the modem starts up before each session, the delay can reach 1-3 minutes.
Could you help me please with this issue?
Thanks.
Device: WP8548
IMEI: ----
IMEISV: ----
FSN: ----
Firmware Version: SWI9X15Y_07.14.01.00 595652d jenkins 2018/10/26 08:34:29
Bootloader Version: SWI9X15Y_07.14.01.00 595652d jenkins 2018/10/26 08:48:35
MCU Version: 002.004
PRI Part Number (PN): 9906350
PRI Revision: 01.00
Carrier PRI Name: GENERIC
Carrier PRI Revision: 001.042_000
SKU: 1103112
Last Reset Cause: Unknown

2

Suggest capturing the wireshark log to isolate if this is server problem

3

We conducted comprehensive checks. Wareshark just shows that there is no data all this time.

4

Then is it server problem?
If no, is it network problem?
Have you compare the wireshark log captured in server and the wireshark log captured in module?
This can confirm if this is network operator problem

5

@maschenkoaa

So I am trying to understand the setup, are you using the WP8 as a modem (PPP dial up? RMNet?) or are you using a Legato application?

Can you elaborate on the step by step procedure you are using. So something such as the following.

  1. Power WP8 up.
  2. Allow it to attach to the network.
  3. Create a data session using Legato application to our server.
  4. Send some data to the server
  5. Takes a significant time for the server to reply.

Regards

Matt

6

Yes. we use Legato application.
The procedure is as follows:

  1. Power WP8 up;
  2. Create a data session using Legato application to our server. (rmnet0 device)
  3. Send some data to the server
  4. we receive data from the server
  5. send an answer
    Strace indicates that send is finished. Wareshark shows that there is no data and no data.
    Then the data appears.
  6. we receive data from the server
  7. send an answer
    Here the delay is a split second. etc.
7

Have you tried nc command instead of legato application?
This can narrow down the root cause and see if legato framwork brings the problem

8

A good idea. I did not know that he was there.

9

Tests with nc showed no problems.

10

probably there is problem in your application then

11

We have simplified our application to a minimum. We also simplified the server. Problem still exists. Is it possible to write your own application bypassing Legato?

12

you can first try to unsandbox the application in .adef file and see if there is improvement.
Another way is to use toolchain to compile your C program application, that will be totally not related to legato framework.

e.g.

/home/owner/legato/packages/legato.toolchain.1.7.3.SWI9X15Y_07112100-wp85-wp750x-native-x86_64-201701091132/resources/native/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-gcc -o sslconnect.arm.o sslconnect.c -lssl -lcrypto

13

Thanks everyone for the help. The native version of the program showed a good result. The replacement of the cellular operator has led to significant changes.