what is the default sharing method based on?

In the Advanced Load Sharing window, select one of the following options:
 IPs, Ports, SPIs (default) provides the best sharing distribution, and is recommended for use. It is
the least “sticky” sharing configuration.
 IPs, Ports should be used only if problems arise when distributing IPSec packets to a few members
although they have the same source and destination IP addresses.
 IPs should be used only if problems arise when distributing IPSec packets or different port packets
to a few members although they have the same source and destination IP addresses. It is the most
“sticky” sharing configuration.