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);