'Send port status
port is an ofp_phy_port
reason is one of OFPPR_xxx'

def send_port_status(self, port, reason):

    assert assert_type('port', port, ofp_phy_port, none_ok=False)
    assert (reason in ofp_port_reason_rev_map.values())
    msg = ofp_port_status(desc=port, reason=reason)
    self.send(msg)
