diff --git a/utils/tracers/ndn-l3-aggregate-tracer.cc b/utils/tracers/ndn-l3-aggregate-tracer.cc
index d1150ae..050e63b 100644
--- a/utils/tracers/ndn-l3-aggregate-tracer.cc
+++ b/utils/tracers/ndn-l3-aggregate-tracer.cc
@@ -358,7 +358,7 @@
 }
 
 void
-L3AggregateTracer::OutData  (Ptr<const ContentObject> data, 
+L3AggregateTracer::OutData  (Ptr<const Data> data, 
                              bool fromCache, Ptr<const Face> face)
 {
   m_stats[face].get<0> ().m_outData ++;
@@ -369,7 +369,7 @@
 }
 
 void
-L3AggregateTracer::InData   (Ptr<const ContentObject> data, 
+L3AggregateTracer::InData   (Ptr<const Data> data, 
                              Ptr<const Face> face)
 {
   m_stats[face].get<0> ().m_inData ++;
@@ -380,7 +380,7 @@
 }
 
 void
-L3AggregateTracer::DropData (Ptr<const ContentObject> data, 
+L3AggregateTracer::DropData (Ptr<const Data> data, 
                              Ptr<const Face> face)
 {
   m_stats[face].get<0> ().m_dropData ++;