diff --git a/handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java b/handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java
index 7b0b56eedc..4f2a538c1e 100644
--- a/handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java
+++ b/handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java
@@ -143,13 +143,7 @@ public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler
      *              {@value #GLOBALCHANNEL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX}.
      */
     protected int userDefinedWritabilityIndex() {
-        if (this instanceof GlobalChannelTrafficShapingHandler) {
-            return GLOBALCHANNEL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
-        } else if (this instanceof GlobalTrafficShapingHandler) {
-            return GLOBAL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
-        } else {
-            return CHANNEL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
-        }
+        return CHANNEL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
     }
 
     /**
diff --git a/handler/src/main/java/io/netty/handler/traffic/GlobalTrafficShapingHandler.java b/handler/src/main/java/io/netty/handler/traffic/GlobalTrafficShapingHandler.java
index 6c4fc58291..a716560a8c 100644
--- a/handler/src/main/java/io/netty/handler/traffic/GlobalTrafficShapingHandler.java
+++ b/handler/src/main/java/io/netty/handler/traffic/GlobalTrafficShapingHandler.java
@@ -111,6 +111,11 @@ public class GlobalTrafficShapingHandler extends AbstractTrafficShapingHandler {
         tc.start();
     }
 
+    @Override
+    protected int userDefinedWritabilityIndex() {
+        return AbstractTrafficShapingHandler.GLOBAL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
+    }
+
     /**
      * Create a new instance.
      *