diff --git a/model/ccnx.h b/model/ccnx.h
index 7c90de9..7fc9217 100644
--- a/model/ccnx.h
+++ b/model/ccnx.h
@@ -49,6 +49,11 @@
 class i_mru {};
 }
 
+#define MILLI_SECOND 1
+#define SECOND 1000
+// default data size
+#define NDN_DEFAULT_DATA_SIZE   1024
+#define NDN_INTEREST_RESET_PERIOD	(10*MILLI_SECOND)
 /**
  * \defgroup ccnx NDN abstraction
  *