diff --git a/whitebox_neutron_tempest_plugin/tests/scenario/test_qos.py b/whitebox_neutron_tempest_plugin/tests/scenario/test_qos.py
index 45dc4d8..c6e86b3 100644
--- a/whitebox_neutron_tempest_plugin/tests/scenario/test_qos.py
+++ b/whitebox_neutron_tempest_plugin/tests/scenario/test_qos.py
@@ -176,7 +176,8 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
             raise ValueError('Unsupported protocol %s' % protocol)
 
     def _test_egress_bw(
-            self, ssh_client, ssh_server, server_ip, protocol, timeout=10):
+            self, ssh_client, ssh_server, server_ip, protocol, maxbitrate,
+            timeout=6):
         utils.kill_iperf_process(ssh_server)
         utils.kill_iperf_process(ssh_client)
 
@@ -196,7 +197,7 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
                           port=self.IPERF_PORT,
                           protocol_param=protocol_param,
                           timeout=timeout,
-                          maxbitrate=self.MIN_KBPS_NO_BWLIMIT * 2000))
+                          maxbitrate=maxbitrate))
         LOG.debug('Run iperf3 command on client: %s', client_cmd)
         ssh_client.exec_command(client_cmd)
         time.sleep(0.1)
@@ -204,7 +205,8 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
             ssh_server, iperf_server_filename))
 
     def _test_ingress_bw(
-            self, ssh_client, ssh_server, server_ip, protocol, timeout=10):
+            self, ssh_client, ssh_server, server_ip, protocol, maxbitrate,
+            timeout=6):
         utils.kill_iperf_process(ssh_server)
         utils.kill_iperf_process(ssh_client)
 
@@ -220,7 +222,7 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
                       '-R -J > {output_file}'.format(
                           server_ip=server_ip, port=self.IPERF_PORT,
                           protocol_param=protocol_param, timeout=timeout,
-                          maxbitrate=self.MIN_KBPS_NO_BWLIMIT * 2000,
+                          maxbitrate=maxbitrate,
                           output_file=iperf_client_filename))
         LOG.debug('Run iperf3 command on client: %s', client_cmd)
         ssh_client.exec_command(client_cmd)
@@ -229,6 +231,13 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
             ssh_client, iperf_client_filename))
 
     def _calculate_bw(self, perf_measures):
+        # For rocky images, final interval is ignored
+        # TODO(eolivare): provide link to iperf/rocky bug
+        intervals_end = (len(perf_measures['intervals'])
+                         if self.username != "rocky"
+                         else len(perf_measures['intervals']) - 1)
+        intervals = perf_measures['intervals'][:intervals_end]
+
         # First 3 for ovs envs, 2 for ovn sriov envs and 1 for normal ovn
         # intervals are removed because BW measured during it is not
         # limited - it takes ~2-4 seconds to traffic shaping algorithm to apply
@@ -240,14 +249,8 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
             intervals_start = 2
         else:
             intervals_start = 1
-
-        # For rocky images, final interval is ignored
-        # TODO(eolivare): provide link to iperf/rocky bug
-        intervals_end = (len(perf_measures['intervals'])
-                         if self.username != "rocky"
-                         else len(perf_measures['intervals']) - 1)
-
-        intervals = perf_measures['intervals'][intervals_start:intervals_end]
+        if len(intervals) > intervals_start + 1:
+            intervals = intervals[intervals_start:]
 
         bits_received = sum([interval['sum']['bytes'] * 8
                              for interval in intervals])
@@ -284,12 +287,20 @@ class QosBaseTest(test_qos.QoSTestMixin, base.TrafficFlowTest):
             test_bw_method = self._test_ingress_bw
             direction = 'ingress'
 
+        # NOTE: with traffic shaping, if the bitrate exceeds the BW limit, the
+        # excees traffic is buffered and sent once the iperf3 client has ended
+        # sending traffic, but this could lead to an iperf error:
+        # "control socket has closed unexpectedly"
+        # due to this we limit the bitrate to 1.5 * bw_limit
+        maxbitrate = (bw_limit * 1.5 if bw_limit is not None
+                      else self.MIN_KBPS_NO_BWLIMIT * 2000)
+
         # egress: send payload from client to server
         # ingress: download payload from server to client
         for server_ip in server_ips:
             perf_measures = test_bw_method(
                 client['ssh_client'], server['ssh_client'],
-                server_ip, protocol)
+                server_ip, protocol, maxbitrate=maxbitrate)
             LOG.debug('perf_measures = %s', perf_measures)
 
             # verify bw limit