EHS6 AT^SISW=x,n Response always show big value <unackData> | Thales IoT Developer Community
October 19, 2020 - 10:09pm, 627 views
Hi Team,
We have been facing problems of missing data on the TCP Listener. Device keeps sending data and the data is not showing up on the listener. So, we have analysed the SISW response and what we have observed that SISW response shows the unacked data bytes keeps on increasing.
| AT^SISS=0,address,"socktcp://xx.***.***.***:***xx" | ||
| OK | ||
| AT^SISO=0 | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT^SISW=0,406 | 1dc | |
| ^SISW: 0,406,0 | Sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1db | |
| ^SISW: 0,380,406 | Sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,406 | 1da | |
| ^SISW: 0,406,786 | Sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1d9 | |
| ^SISW: 0,380,1192 | Sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1d8 | |
| ^SISW: 0,380,0 | Sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1d7 | |
| ^SISW: 0,380,380 | Failed | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1d6 | |
| ^SISW: 0,380,760 | Failed | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,380 | 1d5 | |
| ^SISW: 0,380,1140 | Failed | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | Continuos | |
| AT^SISW=0,379 | Failing | |
| ^SISW: 0,379,5371 | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| As Listener was not receiving anything | ||
| ^SIS: 0,0,48,"Remote peer has closed the connection" | Session closed by the listener after 10-20 seconds | |
| ^SISR: 0,2 | ||
| AT^SISW=0,405 | ||
| ERROR | ||
| Started again | ||
| ^SISW: 0,1 | ||
| AT^SISW=0,406 | 1d9 | |
| ^SISW: 0,406,0 | sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,405 | 1c9 | |
| ^SISW: 0,405,406 | sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,379 | 1c8 | |
| ^SISW: 0,379,0 | sent | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,379 | Sent | |
| ^SISW: 0,379,0 | 7 | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | Sent | |
| OK | 6 | |
| AT^SISW=0,379 | ||
| ^SISW: 0,379,0 | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | ||
| AT^SISW=0,379 | Failed | |
| ^SISW: 0,379,0 | 5 | |
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | Failed | |
| AT^SISW=0,379 | 4 | |
| ^SISW: 0,379,379 | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | Failed | |
| AT^SISW=0,405 | ||
| ^SISW: 0,405,758 | 3 | |
| Failed | ||
| OK | ||
| ^SISW: 0,1 | ||
| AT | ||
| OK | 2 | |
| AT^SISW=0,405 | Failed | |
| ERROR | ||
| ^SIS: 0,0,48,"Remote peer has closed the connection" | ||
As per our observation if modem shows this behavior of data clogging at TCP end then it remains in the state. Is there is any way to come out of this state when modem flush the previous data and start again on new PDP session. Or if there is any command in EHS6 which can give us the status of data sent failed. so, that we can stop sending the data?
We don't understand when should be stop sending data as per the <unackData> in the SISW response. As sometimes when it shown 786 bytes in <unackData> then also it was able to send those bytes.
Please let us know how we can achieve 100% data transmission with this kind of problems. We have done everything on the server side to validate that it only shows up session is opened but not getting any payload.
Hello,
It seems that the data is not acknowledged on TCP layer. In such case there are retransmissions. Initial retransmission timeout, maximum number of retransmissions and overall TCP timeout for outstanding connections are configurable - please see AT^SCFG command for details. In your log it seems that after the connection opening some data was acknowledged. So there also should be some data received by the server. And then the problem started - unacknowledged data was increasing. But it was the remote server that has initiated the connection closing in both cases.
You can use AT^SISI? command to check the internet service status which also includes unacknowledged data.
Maybe you should also monitor the wireless network connection parameters ( for instance AT^SMONI, AT+CSQ, AT+CREG, AT+CGREG). If there is a problem with data transmission it is possible that for instance there is a poor signal strength or quality.
Or maybe there is a problem on the other side for instance with the server connection, overload etc.
How frequently do you observe these problems? Does it depend on the location, device etc. Is it reproducible on many devices? Have you tried with some other operator? What is the module's firmware ('ATI1' reply)?
Regards,
Bartłomiej