diff --git a/tempest/api/compute/servers/test_attach_interfaces.py b/tempest/api/compute/servers/test_attach_interfaces.py
index 0248c65..3c057ac 100644
--- a/tempest/api/compute/servers/test_attach_interfaces.py
+++ b/tempest/api/compute/servers/test_attach_interfaces.py
@@ -123,7 +123,7 @@
             server['id'], port_id=port_id)['interfaceAttachment']
         iface = waiters.wait_for_interface_status(
             self.interfaces_client, server['id'], iface['port_id'], 'ACTIVE')
-        self._check_interface(iface, port_id=port_id)
+        self._check_interface(iface, port_id=port_id, network_id=network_id)
         return iface
 
     def _test_create_interface_by_fixed_ips(self, server, ifs):
diff --git a/tempest/api/network/base.py b/tempest/api/network/base.py
index c2a67e3..bdfda0a 100644
--- a/tempest/api/network/base.py
+++ b/tempest/api/network/base.py
@@ -92,7 +92,6 @@
         cls.subnets = []
         cls.ports = []
         cls.routers = []
-        cls.floating_ips = []
         cls.ethertype = "IPv" + str(cls._ip_version)
         if cls._ip_version == 4:
             cls.cidr = netaddr.IPNetwork(CONF.network.project_network_cidr)
@@ -104,11 +103,6 @@
     @classmethod
     def resource_cleanup(cls):
         if CONF.service_available.neutron:
-            # Clean up floating IPs
-            for floating_ip in cls.floating_ips:
-                test_utils.call_and_ignore_notfound_exc(
-                    cls.floating_ips_client.delete_floatingip,
-                    floating_ip['id'])
             # Clean up ports
             for port in cls.ports:
                 test_utils.call_and_ignore_notfound_exc(
@@ -222,7 +216,9 @@
         body = cls.floating_ips_client.create_floatingip(
             floating_network_id=external_network_id)
         fip = body['floatingip']
-        cls.floating_ips.append(fip)
+        cls.addClassResourceCleanup(test_utils.call_and_ignore_notfound_exc,
+                                    cls.floating_ips_client.delete_floatingip,
+                                    fip['id'])
         return fip
 
     @classmethod
diff --git a/tempest/api/volume/test_volumes_extend.py b/tempest/api/volume/test_volumes_extend.py
index de28a30..b73bdf2 100644
--- a/tempest/api/volume/test_volumes_extend.py
+++ b/tempest/api/volume/test_volumes_extend.py
@@ -18,6 +18,7 @@
 import testtools
 
 from tempest.api.volume import base
+from tempest.common import utils
 from tempest.common import waiters
 from tempest import config
 from tempest.lib import decorators
@@ -104,6 +105,7 @@
     @decorators.idempotent_id('301f5a30-1c6f-4ea0-be1a-91fd28d44354')
     @testtools.skipUnless(CONF.volume_feature_enabled.extend_attached_volume,
                           "Attached volume extend is disabled.")
+    @utils.services('compute')
     def test_extend_attached_volume(self):
         """This is a happy path test which does the following:
 
diff --git a/tempest/lib/exceptions.py b/tempest/lib/exceptions.py
index 9b2e87e..13af890 100644
--- a/tempest/lib/exceptions.py
+++ b/tempest/lib/exceptions.py
@@ -96,7 +96,7 @@
 
 class Conflict(ClientRestClientException):
     status_code = 409
-    message = "An object with that identifier already exists"
+    message = "Conflict with state of target resource"
 
 
 class Gone(ClientRestClientException):
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index 6332c6d..ff8837f 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -421,6 +421,10 @@
     def test_mtu_sized_frames(self):
         """Validate that network MTU sized frames fit through."""
         self._setup_network_and_servers()
+        # first check that connectivity works in general for the instance
+        self.check_public_network_connectivity(should_connect=True)
+        # now that we checked general connectivity, test that full size frames
+        # can also pass between nodes
         self.check_public_network_connectivity(
             should_connect=True, mtu=self.network['mtu'])