diff --git a/environments/network-isolation.j2.yaml b/environments/network-isolation.j2.yaml
index 3ef9b27529..6a7318fcae 100644
--- a/environments/network-isolation.j2.yaml
+++ b/environments/network-isolation.j2.yaml
@@ -13,7 +13,7 @@
 resource_registry:
   # networks as defined in network_data.yaml
   {%- for network in networks if network.enabled|default(true) %}
-  OS::TripleO::Network::{{network.name}}: ../network/{{network.name.lower()}}.yaml
+  OS::TripleO::Network::{{network.name}}: ../network/{{network.name_lower|default(network.name.lower())}}.yaml
   {%- endfor %}
 
   # Port assignments for the VIPs