diff --git a/doc/install-guide/section_nova-networking-compute-node.xml b/doc/install-guide/section_nova-networking-compute-node.xml
index dc9c87b189..0cab54de55 100644
--- a/doc/install-guide/section_nova-networking-compute-node.xml
+++ b/doc/install-guide/section_nova-networking-compute-node.xml
@@ -46,7 +46,9 @@ flat_interface = <replaceable>INTERFACE_NAME</replaceable>
 public_interface = <replaceable>INTERFACE_NAME</replaceable></programlisting>
           <para>Replace <replaceable>INTERFACE_NAME</replaceable> with the
             actual interface name for the external network. For example,
-            <emphasis>eth1</emphasis> or <emphasis>ens224</emphasis>.</para>
+            <emphasis>eth1</emphasis> or <emphasis>ens224</emphasis>. You can
+            also leave these two parameters undefined if you are serving multiple
+            networks with individual bridges for each.</para>
         </step>
       </substeps>
     </step>