port of router is down after set gateway to external net.

Operation:
neutron net-create ci-ext-net --router:external True --provider:physical_network physnet1 --provider:network_type vlan --provider:segmentation_id 1000

neutron subnet-create ci-ext-net --name ci-ext-subnet --allocation-pool start=162.3.130.100,end=162.3.130.130 --disable-dhcp --gateway 162.3.110.1 162.3.0.0/16

neutron router-create --distribute False ci-ext-router

neutron router-gateway-set <CI_EXT_ROUTER_ID> <CI_EXT_NET_ID>

Then from qrouter to ping gateway: 162.3.110.1, it is not ok
# ip netns exec qrouter-a2825c15-b804-480f-a9f0-1d85a1202775 ping 162.3.110.1
PING 162.3.110.1 (162.3.110.1) 56(84) bytes of data.
From 162.3.130.104: icmp_seq=2 Destination Host Unreachable
From 162.3.130.104: icmp_seq=3 Destination Host Unreachable
From 162.3.130.104: icmp_seq=4 Destination Host Unreachable
^C
--- 162.3.110.1 ping statistics ---
4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2999ms
, pipe 3

 # neutron router-show a2825c15-b804-480f-a9f0-1d85a1202775
+-----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+-----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| admin_state_up | True |
| distributed | False |
| external_gateway_info | {"network_id": "a65caeda-dfcd-4ce5-8023-fa4063b54a79", "enable_snat": true, "external_fixed_ips": [{"subnet_id": "a4e05935-5aab-4dd3-b898-45cd69343c14", "ip_address": "162.3.130.104"}]} |
| ha | False |
| id | a2825c15-b804-480f-a9f0-1d85a1202775 |
| name | ci-ext-router |
| routes | |
| status | ACTIVE |
| tenant_id | f1d64e22d48b46f7b807ac44d4078029 |
+-----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 # neutron port-list
+--------------------------------------+-----------------------+-------------------+--------------------------------------------------------------------------------------+
| id | name | mac_address | fixed_ips |
+--------------------------------------+-----------------------+-------------------+--------------------------------------------------------------------------------------+
| 187fd8dd-8a6f-4b9c-877d-b29fd1595d22 | external_om | fa:16:3e:d2:90:91 | {"subnet_id": "859d5522-ff7e-4265-8323-f3470de69c50", "ip_address": "10.9.0.3"} |
| 1c2a2a8d-6322-48b6-a30e-0c403b70f95d | external_om | fa:16:3e:d2:2e:28 | {"subnet_id": "859d5522-ff7e-4265-8323-f3470de69c50", "ip_address": "10.9.0.4"} |
| 2636ce17-6cc6-48fe-9ab3-47c2932193ea | distributed_dhcp_port | fa:16:3e:97:07:99 | {"subnet_id": "029a1d41-58e4-4001-946e-be70dfaadb6e", "ip_address": "182.3.145.2"} |
| 2b746202-ee46-4d95-9cd0-58f9ce9a9699 | | fa:16:3e:7e:59:25 | {"subnet_id": "a4e05935-5aab-4dd3-b898-45cd69343c14", "ip_address": "162.3.130.104"} |
| 6ccc5ace-36f2-4f8e-9771-4cee7c7fbd67 | distributed_dhcp_port | fa:16:3e:e3:33:c8 | {"subnet_id": "c42e4c8c-7762-495a-83a5-3953bbe639b9", "ip_address": "10.1.10.2"} |
| 72bdb8eb-dd45-479e-aaca-658bbec5842c | | fa:16:3e:d8:2d:2d | {"subnet_id": "c42e4c8c-7762-495a-83a5-3953bbe639b9", "ip_address": "10.1.10.29"} |
| 7a2d2964-ee4b-458c-9226-f694a15a6e01 | | fa:16:3e:2f:17:ab | {"subnet_id": "c42e4c8c-7762-495a-83a5-3953bbe639b9", "ip_address": "10.1.10.21"} |
| 8c4f349d-3840-41a6-a4e5-4078d65c20f5 | distributed_dhcp_port | fa:16:3e:13:dc:7c | {"subnet_id": "859d5522-ff7e-4265-8323-f3470de69c50", "ip_address": "10.9.0.2"} |
| a7475c8d-905f-44d8-a93f-9279b5b69fb7 | | fa:16:3e:dc:0c:c8 | {"subnet_id": "a4e05935-5aab-4dd3-b898-45cd69343c14", "ip_address": "162.3.130.103"} |
| ae6cf189-980e-415e-a9c6-354f2aee0194 | distributed_dhcp_port | fa:16:3e:69:7e:b0 | {"subnet_id": "d7bcb1af-76e5-4e67-9586-2c58744fb79b", "ip_address": "10.10.10.2"} |
| da0f6329-8925-44f0-8ce8-f292f0d7814c | | fa:16:3e:1d:86:d8 | {"subnet_id": "029a1d41-58e4-4001-946e-be70dfaadb6e", "ip_address": "182.3.145.3"} |
| e0ff72ab-30d3-408b-8f14-e3212129080e | | fa:16:3e:4d:9f:d0 | {"subnet_id": "a4e05935-5aab-4dd3-b898-45cd69343c14", "ip_address": "162.3.130.100"} |
| e522abf1-e6df-49fe-8471-a47b4f4f62a7 | external_om | fa:16:3e:13:c3:e4 | {"subnet_id": "859d5522-ff7e-4265-8323-f3470de69c50", "ip_address": "10.9.0.5"} |
| f5731a32-8ae7-49cd-942d-48c782a3a9b8 | | fa:16:3e:e3:ae:b6 | {"subnet_id": "c42e4c8c-7762-495a-83a5-3953bbe639b9", "ip_address": "10.1.10.20"} |
| fa516017-62cf-4305-b564-8659e1f5f49b | | fa:16:3e:48:43:61 | {"subnet_id": "c42e4c8c-7762-495a-83a5-3953bbe639b9", "ip_address": "10.1.10.37"} |
+--------------------------------------+-----------------------+-------------------+--------------------------------------------------------------------------------------+
# neutron port-show 2b746202-ee46-4d95-9cd0-58f9ce9a9699
+-----------------------+--------------------------------------------------------------------------------------+
| Field | Value |
+-----------------------+--------------------------------------------------------------------------------------+
| admin_state_up | True |
| allowed_address_pairs | |
| binding:host_id | 804BE800-9491-11E2-8567-000000821800 |
| binding:profile | {} |
| binding:vif_details | {} |
| binding:vif_type | binding_failed |
| binding:vnic_type | normal |
| device_id | a2825c15-b804-480f-a9f0-1d85a1202775 |
| device_owner | network:router_gateway |
| extra_dhcp_opts | |
| fixed_ips | {"subnet_id": "a4e05935-5aab-4dd3-b898-45cd69343c14", "ip_address": "162.3.130.104"} |
| id | 2b746202-ee46-4d95-9cd0-58f9ce9a9699 |
| mac_address | fa:16:3e:7e:59:25 |
| name | |
| network_id | a65caeda-dfcd-4ce5-8023-fa4063b54a79 |
| security_groups | |
| status | DOWN |
| tenant_id | |
+-----------------------+--------------------------------------------------------------------------------------+