I have GE865 modem with fw 10.01.001 and I am periodically opening connection to remote server (cca every minute). This works ok most of the time but sometimes on some devices I have +CME ERROR: 559 – timeout in opening socket.
My application is doing some retries and from the logs this state when it’s not possible to open socket lasts from 5 minutes to almost an hour. I have asked mobile operator for the logs from that time and I can see that the modem sends initial [SYN] packet to which server responds with [SYN, ACK]. However instead of finishing handshake with ACK, modem retransmitts its [SYN] packet as if it did not receive the [SYN, ACK] from server (this is in wireshark marked as TCP Spurious Retransmission). Also I know that ther server is working OK, because other devices connected to it did not have this problem at that time.
Is there something I can do with this, maybe some TCP timeouts configuration ?
Thanks
Roman Bris
Hi, I suppose that you took a Wireshark log on the server side and according to your description, it seems that the [SYN, ACK] is not being received back by the module. The timeout of the TCP retransmission is fixed, but even changing the timeout won?t help, if the [SYN, ACK] is not received back. The module can retry up to 10 times (according to AT#SCFG setting) and then it will raise an error. When the issue happens, can you try to connect to a different server, for example our echo test server: AT#SD=1,0,10510,”modules.telit.com”
If even this connection doesn?t work, can you try to deactivate and reactivate the context with this sequence: AT#SGACT=1,0 AT#SGACT? (wait for 1,0) AT#SGACT=1,1
Hi, thanks for the reponse.
actually it was the mobile operator who took the logs (so in the middle between device and server).
Why connecting to a different server? Sure I can add that but as I said I know for a fact that server was running because other devices did not had problem with it at that time. I will add the context reactivation and see if that helps.
Hi,
I asked you to test with a different server just for refference. Normally any additional information is usefull.
OK, let’s wait for the context reactivation test results.
We use cookies to enhance your browsing experience and help us improve our websites. To improve our website, we carefully select third parties that use cookies to allow us to serve specific content and achieve the purposes set out in our cookie policy. For more information on how to make adjustments through your browser to the cookies being used on your device, please click Find Out More link. By closing this banner or continuing to browse our website, you agree to our use of such cookies. FIND OUT MORE
Hi,
I have GE865 modem with fw 10.01.001 and I am periodically opening connection to remote server (cca every minute). This works ok most of the time but sometimes on some devices I have +CME ERROR: 559 – timeout in opening socket.
My application is doing some retries and from the logs this state when it’s not possible to open socket lasts from 5 minutes to almost an hour. I have asked mobile operator for the logs from that time and I can see that the modem sends initial [SYN] packet to which server responds with [SYN, ACK]. However instead of finishing handshake with ACK, modem retransmitts its [SYN] packet as if it did not receive the [SYN, ACK] from server (this is in wireshark marked as TCP Spurious Retransmission). Also I know that ther server is working OK, because other devices connected to it did not have this problem at that time.
Is there something I can do with this, maybe some TCP timeouts configuration ?
Thanks
Roman Bris
Hi,
I suppose that you took a Wireshark log on the server side and according to your description, it seems that the [SYN, ACK] is not being received back by the module.
The timeout of the TCP retransmission is fixed, but even changing the timeout won?t help, if the [SYN, ACK] is not received back.
The module can retry up to 10 times (according to AT#SCFG setting) and then it will raise an error.
When the issue happens, can you try to connect to a different server, for example our echo test server:
AT#SD=1,0,10510,”modules.telit.com”
If even this connection doesn?t work, can you try to deactivate and reactivate the context with this sequence:
AT#SGACT=1,0
AT#SGACT? (wait for 1,0)
AT#SGACT=1,1
Hi, thanks for the reponse.
actually it was the mobile operator who took the logs (so in the middle between device and server).
Why connecting to a different server? Sure I can add that but as I said I know for a fact that server was running because other devices did not had problem with it at that time. I will add the context reactivation and see if that helps.
Hi,
I asked you to test with a different server just for refference.
Normally any additional information is usefull.
OK, let’s wait for the context reactivation test results.