diff --git a/utils/tracers/ndn-app-delay-tracer.hpp b/utils/tracers/ndn-app-delay-tracer.hpp
index 64b695a..72cccec 100644
--- a/utils/tracers/ndn-app-delay-tracer.hpp
+++ b/utils/tracers/ndn-app-delay-tracer.hpp
@@ -21,6 +21,8 @@
 #ifndef CCNX_APP_DELAY_TRACER_H
 #define CCNX_APP_DELAY_TRACER_H
 
+#include "ns3/ndnSIM/model/ndn-common.hpp"
+
 #include "ns3/ptr.h"
 #include "ns3/simple-ref-count.h"
 #include <ns3/nstime.h>