diff --git a/de/heat-templates/fragments/NetworkAccVM.yaml b/de/heat-templates/fragments/NetworkAccVM.yaml
index 2e1b3f2..b2f322a 100644
--- a/de/heat-templates/fragments/NetworkAccVM.yaml
+++ b/de/heat-templates/fragments/NetworkAccVM.yaml
@@ -40,6 +40,8 @@
 
   network:
     type: OS::Neutron::Net
+    properties:
+      value_specs: { mtu: 9046 }
   subnet:
     type: OS::Neutron::Subnet
     properties: