diff --git a/utils/ndn-rtt-estimator.cc b/utils/ndn-rtt-estimator.cc
index 93193d2..b0d2b83 100644
--- a/utils/ndn-rtt-estimator.cc
+++ b/utils/ndn-rtt-estimator.cc
@@ -158,6 +158,12 @@
   NS_LOG_FUNCTION (this);
 }
 
+TypeId
+RttEstimator::GetInstanceTypeId (void) const
+{
+  return GetTypeId ();
+}
+
 void RttEstimator::SentSeq (SequenceNumber32 seq, uint32_t size)
 {
   NS_LOG_FUNCTION (this << seq << size);
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.
diff --git a/utils/ndn-rtt-mean-deviation.cc b/utils/ndn-rtt-mean-deviation.cc
index c05ad75..88cebaa 100644
--- a/utils/ndn-rtt-mean-deviation.cc
+++ b/utils/ndn-rtt-mean-deviation.cc
@@ -74,6 +74,12 @@
   NS_LOG_FUNCTION (this);
 }
 
+TypeId
+RttMeanDeviation::GetInstanceTypeId (void) const
+{
+  return GetTypeId ();
+}
+
 void RttMeanDeviation::Measurement (Time m)
 {
   NS_LOG_FUNCTION (this << m);
diff --git a/utils/ndn-rtt-mean-deviation.h b/utils/ndn-rtt-mean-deviation.h
index e8b419c..02d8fac 100644
--- a/utils/ndn-rtt-mean-deviation.h
+++ b/utils/ndn-rtt-mean-deviation.h
@@ -51,6 +51,8 @@
   RttMeanDeviation ();
   RttMeanDeviation (const RttMeanDeviation&);
 
+  virtual TypeId GetInstanceTypeId (void) const;
+
   void SentSeq (SequenceNumber32 seq, uint32_t size);
   Time AckSeq (SequenceNumber32 ackSeq);
   void Measurement (Time measure);