diff --git a/include/base/frame/frame_base.h b/include/base/frame/frame_base.h
index fbe3914ab8b76c290d0bcdb13680e6cbea6493cd..cd178138fa2870fe201ed96944bfa2216d9db841 100644
--- a/include/base/frame/frame_base.h
+++ b/include/base/frame/frame_base.h
@@ -74,6 +74,7 @@ class FrameBase : public NodeBase, public std::enable_shared_from_this<FrameBase
 
         // get type
         bool isKey() const;
+        bool isAuxiliary() const;
         bool isEstimated() const;
 
         // set type
@@ -177,6 +178,11 @@ inline bool FrameBase::isKey() const
     return (type_ == KEY);
 }
 
+inline bool FrameBase::isAuxiliary() const
+{
+    return (type_ == AUXILIARY);
+}
+
 inline bool FrameBase::isEstimated() const
 {
     return (type_ == KEY || type_ == AUXILIARY);