Internet Offline: IPv6 ipref
$ iperf -s -V
$ iperf -c <Server IPv6 Address> -V>
Use the -F or -I option. If you want to test how your network performs with compressed / uncompressed streams, just create representative streams and use the -F option to test it. This is usually due to the link layer compressing data.
The -F option is for file input. The -I option is for input from stdin.
Client: $ iperf -c <server address> -F <file-name> Client: $ iperf -c <server address> -I