Arm Mbed OS support forum

Reuse session in FTP problem can't perform abbreviate handshake

I just use mbedtls on a device use FTP via 4G TCPIP. I try to connect to IIS FTP Server on windows server 2012 R2.
When I finished porting mbedtls on my device, it always performs a full handshake on both the control channel and the data channel, with successful data transferring.
Now I want to reuse the session ID from the first response in server hello when establish control connection and perform an abbreviate handshake in following data channel. But the responded session ID from the server is not the session ID sent in client hello; finally, there is still a full handshake performed.

In order to guarantee the server, I use cuteftp and filezilla to connect to same server, resulting with the data channel performing an good abbreviate handshake.

So can anyone help me on this topic?