diff --git a/api-ref/source/v2/lbaas-v2.inc b/api-ref/source/v2/lbaas-v2.inc
index 7b05527..662f51e 100644
--- a/api-ref/source/v2/lbaas-v2.inc
+++ b/api-ref/source/v2/lbaas-v2.inc
@@ -162,6 +162,12 @@ load balancer. You can set this attribute to any service provider
 with a ``LOADBALANCER`` service type. Setting both a flavor and a
 provider will result in a conflict error.
 
+Finally, ``vip_network_id`` can be used in place of
+``vip_subnet_id``. When this option is used, the VIP port is
+created on the given network using the default behavior. If
+assigned multiple fixed IPs, an IPv4 addresses is chosen as the
+VIP in preference to IPv6 addresses.
+
 Example: Create a load balancer
 
 Error response codes: 201,404,409,401,413,503,500
@@ -206,6 +212,7 @@ Response Parameters
    - id: id
    - loadbalancer: loadbalancer
    - name: name
+   - vip_network_id: vip_network_id
 
 Show load balancer details
 ==========================
diff --git a/api-ref/source/v2/parameters.yaml b/api-ref/source/v2/parameters.yaml
index aea07ad..0c249b5 100644
--- a/api-ref/source/v2/parameters.yaml
+++ b/api-ref/source/v2/parameters.yaml
@@ -4084,12 +4084,21 @@ vip_id:
   in: body
   required: true
   type: string
+vip_network_id:
+  description: |
+    The ID of the network on which to allocate
+    the virtual IP (VIP) address. This option is
+    required if no vip_subnet_id is given.
+  in: body
+  required: false
+  type: string
 vip_subnet_id:
   description: |
-    The UUID of the subnet on which to allocate the
-    virtual IP (VIP) address.
+    The ID of the subnet on which to allocate the
+    virtual IP (VIP) address. This option is required
+    if no vip_network_id is given.
   in: body
-  required: true
+  required: false
   type: string
 vips:
   description: |