if datapath.id==1:
            out_port=2
            actions=[parser.OFPActionOutput(out_port)]
            match=parser.OFPMatch(eth_type=0x0800, ipv4_src="10.0.0.1", ipv4_dst="10.0.0.2")
            self.add_flow(datapath, match, actions, DEFAULT_PRIORITY, 1000, 1000)
            out_port =1
            actions = [parser.OFPActionOutput(out_port)]
            match=parser.OFPMatch(eth_type=0x0800, ipv4_src="10.0.0.2", ipv4_dst="10.0.0.1")
            self.add_flow(datapath, match, actions, DEFAULT_PRIORITY, 1000, 1000)