Adding comments to external ext
diff --git a/openstack/networking/v2/extensions/external/requests.go b/openstack/networking/v2/extensions/external/requests.go
index f195cfa..afdd428 100644
--- a/openstack/networking/v2/extensions/external/requests.go
+++ b/openstack/networking/v2/extensions/external/requests.go
@@ -2,6 +2,8 @@
 
 import "github.com/rackspace/gophercloud/openstack/networking/v2/networks"
 
+// AdminState gives users a solid type to work with for create and update
+// operations. It is recommended that users use the `Up` and `Down` enums.
 type AdminState *bool
 
 // Convenience vars for AdminStateUp values.
@@ -9,16 +11,19 @@
 	iTrue  = true
 	iFalse = false
 
-	Nothing AdminState = nil
-	Up      AdminState = &iTrue
-	Down    AdminState = &iFalse
+	Up   AdminState = &iTrue
+	Down AdminState = &iFalse
 )
 
+// CreateOpts is the structure used when creating new external network
+// resources. It embeds networks.CreateOpts and so inherits all of its required
+// and optional fields, with the addition of the External field.
 type CreateOpts struct {
 	Parent   networks.CreateOpts
 	External bool
 }
 
+// ToNetworkCreateMap casts a CreateOpts struct to a map.
 func (o CreateOpts) ToNetworkCreateMap() map[string]map[string]interface{} {
 	outer := o.Parent.ToNetworkCreateMap()
 
@@ -27,11 +32,15 @@
 	return outer
 }
 
+// UpdateOpts is the structure used when updating existing external network
+// resources. It embeds networks.UpdateOpts and so inherits all of its required
+// and optional fields, with the addition of the External field.
 type UpdateOpts struct {
 	Parent   networks.UpdateOpts
 	External bool
 }
 
+// ToNetworkUpdateMap casts an UpdateOpts struct to a map.
 func (o UpdateOpts) ToNetworkUpdateMap() map[string]map[string]interface{} {
 	outer := o.Parent.ToNetworkUpdateMap()