[lwip-users] TCP spurious Retransmission and Dup Ack issue

[Axel Lin]

Hi,
I'm using netconn API.
While testing lwIPv2.0.1, I found my device seems stuck after running
for a couple minutes.

My device running lwIP (192.168.0.103) as a tcp client.
A Linux laptop (192.168.0.104) running "netcat -l 8088" to receive data.

In my use case, it's one-direction data transfer as lwIP device
sending data to the linux server.
After running for a couple minutes, I got a lot "TCP Spurious
Retransmission and TCP Dup ACK",
then the transfer stuck and abort in the end.

I upload my wireshark logs to below link: (I capture the log twice,
the same symptom)
https://www.dropbox.com/sh/35pl7ogm37xdccq/AADJiUZRAcO5z8lmbU6oaKSna?dl=0

on log1, this issue begins from No. 44908.
on log2, this issue begins from No. 19090.

Appreciate if someone can take a look at this.

Thanks,
Axel