@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
	def _packet_in_handler(self, ev):
		msg = ev.msg
		data = msg.data
		datapath = msg.datapath
		dpid = datapath.id

		pkt = packet.Packet(data=data)
		if pkt.get_protocol(lldp.lldp):
			switch = get_switch(self.switches, dpid)[0]

			ports = switch.ports
			self.northbound.define_ports(dpid, ports)

			links = get_link(self.switches, dpid)
			self.northbound.define_links(dpid, links)