A network system connects with a number of individual processes that can mutually
send and receive a broadcast message specified with no destination and a message
specified with a specific process and that can change their states to parent or
child processes. When a first process is a parent process and second through fourth
processes are child processes, the four processes constitute a group, in which
each of child processes stores the parent process, and the parent process stores
each of child processes that store the parent process itself. When a new process
that is in another group is connected to this group, the parent process exchanges
a message with the new process for negotiation to determine either whether to be
a parent process or to change to a child process.
