diff --git a/nfv_tempest_plugin/tests/scenario/test_nfv_offload.py b/nfv_tempest_plugin/tests/scenario/test_nfv_offload.py
index ce685e57..3694ead9 100644
--- a/nfv_tempest_plugin/tests/scenario/test_nfv_offload.py
+++ b/nfv_tempest_plugin/tests/scenario/test_nfv_offload.py
@@ -942,6 +942,11 @@ def check_conntrack(self, srv_pair, protocol):
 
         for item in iperf_logs:
             shell_utils.stop_iperf(item['server'], item['log_file'])
+        # sleep for a while to be sure that after stopping iperf,
+        # there is no packet generated by iperf that may break
+        # the following test
+        time.sleep(10)
+
         return errors
 
     def check_conntrack_table(self, hyper, source, protocol, l4_port):