diff --git a/gbpservice/neutron/db/grouppolicy/group_policy_mapping_db.py b/gbpservice/neutron/db/grouppolicy/group_policy_mapping_db.py
index c1f707d96e..a215cdb613 100644
--- a/gbpservice/neutron/db/grouppolicy/group_policy_mapping_db.py
+++ b/gbpservice/neutron/db/grouppolicy/group_policy_mapping_db.py
@@ -214,6 +214,11 @@ def _set_db_np_subnet(self, context, nat_pool, subnet_id):
             db_np.subnet_id = nat_pool['subnet_id']
             context.session.merge(db_np)
 
+    def _get_ptgs_for_subnet(self, context, subnet_id):
+        return [x['policy_target_group_id'] for x in
+            context.session.query(PTGToSubnetAssociation).filter_by(
+                subnet_id=subnet_id)]
+
     @log.log
     def create_policy_target(self, context, policy_target):
         pt = policy_target['policy_target']
diff --git a/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/apic_mapping.py b/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/apic_mapping.py
index def5376b8e..44c88ef866 100644
--- a/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/apic_mapping.py
+++ b/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/apic_mapping.py
@@ -150,6 +150,7 @@ def initialize(self):
         self._setup_rpc()
         self.apic_manager = ApicMappingDriver.get_apic_manager()
         self.name_mapper = self.apic_manager.apic_mapper
+        self.enable_dhcp_opt = self.apic_manager.enable_optimized_dhcp
         self._gbp_plugin = None
 
     def _setup_rpc_listeners(self):
@@ -211,6 +212,7 @@ def is_port_promiscuous(port):
                    'app_profile_name': str(
                        self.apic_manager.app_profile_name),
                    'l2_policy_id': l2_policy_id,
+                   'l3_policy_id': l2p['l3_policy_id'],
                    'tenant_id': port['tenant_id'],
                    'host': port[portbindings.HOST_ID],
                    'ptg_tenant': self.apic_manager.apic.fvTenant.name(
@@ -224,6 +226,7 @@ def is_port_promiscuous(port):
             l3_policy = context._plugin.get_l3_policy(context,
                                                       l2p['l3_policy_id'])
             self._add_ip_mapping_details(context, port_id, l3_policy, details)
+        self._add_network_details(context, port, details)
         return details
 
     def _add_ip_mapping_details(self, context, port_id, l3_policy, details):
@@ -255,6 +258,12 @@ def _add_ip_mapping_details(self, context, port_id, l3_policy, details):
         details['floating_ip'] = fips
         details['ip_mapping'] = ipms
 
+    def _add_network_details(self, context, port, details):
+        details['allowed_address_pairs'] = port['allowed_address_pairs']
+        details['enable_dhcp_optimization'] = self.enable_dhcp_opt
+        details['subnets'] = self._get_subnets(context,
+            filters={'id': [ip['subnet_id'] for ip in port['fixed_ips']]})
+
     def process_port_added(self, plugin_context, port):
         pass
 
@@ -806,6 +815,14 @@ def process_subnet_changed(self, context, old, new):
             if l2p:
                 # Is GBP owned, reflect on APIC
                 self._manage_l2p_subnets(context, l2p['id'], [new], [old])
+        # notify ports in the subnet
+        ptg_ids = self.gbp_plugin._get_ptgs_for_subnet(context, old['id'])
+        pts = self.gbp_plugin.get_policy_targets(
+            context, filters={'policy_target_group_id': ptg_ids})
+        # REVISIT(amit): We may notify more ports than those that are
+        # really affected. Consider checking the port's subnet as well.
+        for pt in pts:
+            self._notify_port_update(context, pt['port_id'])
 
     def process_subnet_added(self, context, subnet):
         l2p = self._network_id_to_l2p(context, subnet['network_id'])
diff --git a/gbpservice/neutron/tests/unit/services/grouppolicy/test_apic_mapping.py b/gbpservice/neutron/tests/unit/services/grouppolicy/test_apic_mapping.py
index 5e9510447b..e949a8c50e 100644
--- a/gbpservice/neutron/tests/unit/services/grouppolicy/test_apic_mapping.py
+++ b/gbpservice/neutron/tests/unit/services/grouppolicy/test_apic_mapping.py
@@ -243,6 +243,9 @@ def test_get_gbp_details(self):
         self.assertEqual(pt1['port_id'], mapping['port_id'])
         self.assertEqual(ptg['id'], mapping['endpoint_group_name'])
         self.assertEqual('someid', mapping['vm-name'])
+        self.assertTrue(mapping['enable_dhcp_optimization'])
+        self.assertEqual(1, len(mapping['subnets']))
+        self.assertEqual(ptg['subnets'][0], mapping['subnets'][0]['id'])
 
     def test_get_gbp_details_shadow(self):
         l2p = self.create_l2_policy()['l2_policy']
@@ -294,6 +297,22 @@ def test_update_ptg_failed(self):
             expected_res_status=400)
         self.assertEqual('InvalidPortForPTG', res['NeutronError']['type'])
 
+    def test_port_notified_on_subnet_change(self):
+        ptg = self.create_policy_target_group()['policy_target_group']
+        pt = self.create_policy_target(
+            policy_target_group_id=ptg['id'])['policy_target']
+        self._bind_port_to_host(pt['port_id'], 'h1')
+
+        subnet = self._get_object('subnets', ptg['subnets'][0], self.api)
+        subnet2 = copy.deepcopy(subnet)
+        subnet2['subnet']['gateway_ip'] = '10.0.0.254'
+
+        self.driver.apic_manager.reset_mock()
+        self.driver.notifier.port_update.reset_mock()
+        self.driver.process_subnet_changed(context.get_admin_context(),
+                                           subnet['subnet'], subnet2['subnet'])
+        self.assertTrue(self.driver.notifier.port_update.called)
+
 
 class TestPolicyTargetGroup(ApicMappingTestCase):