File size 30MB of client_connection_file_transer.pcap

How to reduce the file-size of client _connection_file_transfer.pcap ?

Please look at this faq
A Most important filter can be ‘port not 8080’

You should use tcpdump tags to capture packets specific to your use. Try using port number, device ip’s, etc as filter. You can read this tutorial to learn more tcpdump flags and their use.

Use filters… basically the more filters you apply… The more relevant data you will get… And that reduces the file size