diff --git a/proto/gnmi_ext/gnmi_ext.proto b/proto/gnmi_ext/gnmi_ext.proto
index ada5e39..6b02ca2 100644
--- a/proto/gnmi_ext/gnmi_ext.proto
+++ b/proto/gnmi_ext/gnmi_ext.proto
@@ -28,12 +28,13 @@ option go_package = "github.com/openconfig/gnmi/proto/gnmi_ext";
 // The Extension message contains a single gNMI extension.
 message Extension {
   oneof ext {
-    RegisteredExtension registered_ext = 1;  // A registered extension.
+    RegisteredExtension registered_ext = 1;     // A registered extension.
     // Well known extensions.
-    MasterArbitration master_arbitration = 2;  // Master arbitration extension.
-    History history = 3;                       // History extension.
-    Commit commit = 4;                         // Commit confirmed extension.
-    Depth depth = 5;                           // Depth extension.
+    MasterArbitration master_arbitration = 2;   // Master arbitration extension.
+    History history = 3;                        // History extension.
+    Commit commit = 4;                          // Commit confirmed extension.
+    Depth depth = 5;                            // Depth extension.
+    ConfigSubscription config_subscription = 6; // Config Subscription extension.
   }
 }
 
@@ -159,3 +160,33 @@ message Depth {
   // returned.
   uint32 level = 1;
 }
+
+// ConfigSubscription extension allows clients to subscribe to configuration
+// schema nodes only.
+message ConfigSubscription {
+  oneof action {
+    // ConfigSubscriptionStart is sent by the client in the SubscribeRequest
+    ConfigSubscriptionStart start = 1;
+    // ConfigSubscriptionSyncDone is sent by the server in the SubscribeResponse
+    ConfigSubscriptionSyncDone sync_done = 2;
+  }
+}
+
+// ConfigSubscriptionStart is used to indicate to a target that for a given set
+// of paths in the SubscribeRequest, the client wishes to receive updates
+// for the configuration schema nodes only.
+message ConfigSubscriptionStart {}
+
+// ConfigSubscriptionSyncDone is sent by the server in the SubscribeResponse
+// after all the updates for the configuration schema nodes have been sent.
+message ConfigSubscriptionSyncDone {
+  // ID of a commit confirm operation as assigned by the client
+  // see Commit Confirm extension for more details.
+  string commit_confirm_id = 1;
+  // ID of a commit as might be assigned by the server
+  // when registering a commit operation.
+  string server_commit_id = 2;
+  // If true indicates that the server is done processing the updates related to the
+  // commit_confirm_id and/or server_commit_id.
+  bool done = 3;
+}