diff --git a/utils/trie.h b/utils/trie.h
index 5d440d2..ebaa921 100644
--- a/utils/trie.h
+++ b/utils/trie.h
@@ -38,6 +38,7 @@
 template<typename Payload>
 struct pointer_payload_traits
 {
+  typedef Payload         payload_type;
   typedef Payload*        pointer_type;
   typedef const Payload*  const_pointer_type;
 
@@ -51,6 +52,7 @@
 template<typename Payload>
 struct smart_pointer_payload_traits
 {
+  typedef Payload                 payload_type;
   typedef ns3::Ptr<Payload>       pointer_type;
   typedef ns3::Ptr<const Payload> const_pointer_type;