We are seeing LTE-M communication dropouts on the nRF9160 with firmware 1.3.6
This has occurred several times with multiple devices. The devices are registered on the same cell, but the connection problems don't happen at the same time.
In each case, a previously established, long-lived TCP/IP connection stalls (no more incoming data). Our application detects this and tries to re-open the connection. This requires a DNS lookup (getaddrinfo) which repeatedly fails with EAI_SYSTEM errno=116 (timeout).
We have enabled LTE and IP modem traces. I have attached the textual log files we recorded which contain the modem traces as hexdumps, among other information. I have converted the modem traces to the binary format, which I also attached.
What is strange is that the Cellular Monitor tool fails to convert the problematic time range.
There are about a thousand trace packets in each file, but only fewer than 100 show up in Wireshark. This seems to indicate some kind of abnormal behaviour of the modem. Is this a known issue?
/cfs-file/__key/communityserver-discussions-components-files/4/2654.trace2.log
/cfs-file/__key/communityserver-discussions-components-files/4/3225.trace1.log
/cfs-file/__key/communityserver-discussions-components-files/4/0523.trace3.log
We are aware that a newer firmware version 1.3.7 exists, but we are currently shipping 1.3.6 in our products. The release notes for 1.3.7 don't seem to contain anything related to this, but I may be mistaken.
