def METHOD_NAME(self, ac_id, length, address, isPong):
    if not self.ac_downlink_status.has_key(ac_id):
        self.ac_downlink_status[ac_id] = DownLinkStatus(ac_id, address)
    self.ac_downlink_status[ac_id].rx_msgs += 1
    self.ac_downlink_status[ac_id].rx_bytes += length
    self.ac_downlink_status[ac_id].last_msg_time = time.time()
    if isPong:
        self.ac_downlink_status[ac_id].last_pong_time = time.time() - self.ac_downlink_status[ac_id].last_ping_time