Comment 2 for bug 1585907

Don't mind,port list information after every step as follows(the network has only one subnet):

1.Before subnet added into the router, 'total_ips' of network does not contain 'gateway_ip','used_ips' of network does not contain 'gateway_ip'

[root@localhost devstack]# neutron net-show net_test
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
| admin_state_up | True |
| availability_zone_hints | |
| availability_zones | zone-1 |
| created_at | 2016-05-26T14:44:36 |
| description | |
| id | 83dc21b4-715b-4f74-9db6-012ccf13c8ef |
| ipv4_address_scope | |
| ipv6_address_scope | |
| mtu | 4950 |
| name | net_test |
| provider:network_type | vxlan |
| provider:physical_network | |
| provider:segmentation_id | 1040 |
| qos_policy_id | |
| router:external | False |
| shared | False |
| status | ACTIVE |
| subnets | 63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118 |
| tags | |
| tenant_id | ee4bd2aeeac74bb3ad2b094fc5292cbf |
| updated_at | 2016-05-26T14:44:36 |
| vlan_transparent | False |
+---------------------------+--------------------------------------+
[root@localhost devstack]# neutron port-list|grep 63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118
| 99d84483-f15f-4ec6-97ff-782dc865cc64 | | fa:16:3e:22:54:c8 | {"subnet_id": "63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118", "ip_address": "105.1.1.6"} |

[root@localhost devstack]# neutron net-ip-availability-list
+--------------------------------------+-------------------+-----------+----------+
| network_id | network_name | total_ips | used_ips |
+--------------------------------------+-------------------+-----------+----------+
| 83dc21b4-715b-4f74-9db6-012ccf13c8ef | net_test | 5 | 1 |
+--------------------------------------+-------------------+-----------+----------+

2.After subnet added into the router,'total_ips' of network does not contain 'gateway_ip',However,'used_ips' of network contains 'gateway_ip'

[root@localhost devstack]# neutron router-interface-add router_az_01 subnet=63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118
Added interface 1fcae454-34a9-4b09-9428-c7824a653bf7 to router router_az_01.

[root@localhost devstack]# neutron net-ip-availability-list
+--------------------------------------+-------------------+-----------+----------+
| network_id | network_name | total_ips | used_ips |
+--------------------------------------+-------------------+-----------+----------+
| 83dc21b4-715b-4f74-9db6-012ccf13c8ef | net_test | 5 | 2 |
+--------------------------------------+-------------------+-----------+----------+

[root@localhost devstack]# neutron port-list|grep 63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118
| 1fcae454-34a9-4b09-9428-c7824a653bf7 | | fa:16:3e:a8:e7:62 | {"subnet_id": "63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118", "ip_address": "105.1.1.1"} |
| 99d84483-f15f-4ec6-97ff-782dc865cc64 | | fa:16:3e:22:54:c8 | {"subnet_id": "63aa67d0-55e4-4cb0-8dcb-cdc7d2c83118", "ip_address": "105.1.1.6"} |
[root@localhost devstack]#