diff --git a/tempest/api/network/base.py b/tempest/api/network/base.py
index d75339c..1a23cb6 100644
--- a/tempest/api/network/base.py
+++ b/tempest/api/network/base.py
@@ -49,6 +49,7 @@
         neutron as True
     """
 
+    _interface = 'json'
     force_tenant_isolation = False
 
     # Default to ipv4.