diff --git a/utils/ndn-rtt-estimator.h b/utils/ndn-rtt-estimator.h
index 6bf6aa8..287452e 100644
--- a/utils/ndn-rtt-estimator.h
+++ b/utils/ndn-rtt-estimator.h
@@ -67,6 +67,8 @@
 
   virtual ~RttEstimator();
 
+  virtual TypeId GetInstanceTypeId (void) const;
+
   /**
    * \brief Note that a particular sequence has been sent
    * \param seq the packet sequence number.