when odl is restart,table51's action is drop:

root@controller:~# ovs-ofctl -O openflow13 dump-flows br-int table=51
 cookie=0x803138a, duration=843.323s, table=51, n_packets=82, n_bytes=8692, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:ff:c8:09 actions=load:0x400->NXM_NX_REG6[],resubmit(,220)
 cookie=0x803138a, duration=843.323s, table=51, n_packets=74, n_bytes=8086, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:19:4b:6e actions=load:0x400->NXM_NX_REG6[],resubmit(,220)
 cookie=0x803138a, duration=843.323s, table=51, n_packets=73, n_bytes=7984, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:06:00:39 actions=load:0x400->NXM_NX_REG6[],resubmit(,220)
 cookie=0x803138a, duration=843.323s, table=51, n_packets=74, n_bytes=8026, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:7a:71:be actions=load:0x400->NXM_NX_REG6[],resubmit(,220)
 cookie=0x803138a, duration=843.323s, table=51, n_packets=74, n_bytes=8028, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:ad:e6:d6 actions=load:0x400->NXM_NX_REG6[],resubmit(,220)
 cookie=0x803138a, duration=345.926s, table=51, n_packets=74, n_bytes=8088, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:20:6f:e4 actions=drop
 cookie=0x803138a, duration=345.298s, table=51, n_packets=74, n_bytes=8088, priority=20,metadata=0x138a000000/0xffff000000,dl_dst=fa:16:3e:de:05:89 actions=drop