pssl:[port][:ip]
    Listens for OpenFlow SSL connections on port (default: 6633). The --private-key, --certificate, and --ca-cert options are mandatory when this form is used. By default, connections are not bound to a particular local IP address, but ip may be specified to listen only for connections to the given ip.

ptcp:[port][:ip]
    Listens for OpenFlow TCP connections on port (default: 6633). By default, connections are not bound to a particular local IP address, but ip may be specified to listen only for connections to the given ip.

punix:file
    Listens for OpenFlow connections on the Unix domain server socket named file.