diff --git a/core/util/non-negative-integer.hpp b/core/util/non-negative-integer.hpp
index 08afe34..5b034f7 100644
--- a/core/util/non-negative-integer.hpp
+++ b/core/util/non-negative-integer.hpp
@@ -22,10 +22,12 @@
 #ifndef NDN_DELOREAN_UTIL_NON_NEGATIVE_INTEGER_HPP
 #define NDN_DELOREAN_UTIL_NON_NEGATIVE_INTEGER_HPP
 
-namespace nsl {
+namespace ndn {
+namespace delorean {
 
 typedef uint64_t NonNegativeInteger;
 
-} // namespace nsl
+} // namespace delorean
+} // namespace ndn
 
 #endif // NDN_DELOREAN_UTIL_NON_NEGATIVE_INTEGER_HPP
diff --git a/core/util/timestamp.hpp b/core/util/timestamp.hpp
index a35a09d..cecc046 100644
--- a/core/util/timestamp.hpp
+++ b/core/util/timestamp.hpp
@@ -22,10 +22,12 @@
 #ifndef NDN_DELOREAN_UTIL_TIMESTAMP_HPP
 #define NDN_DELOREAN_UTIL_TIMESTAMP_HPP
 
-namespace nsl {
+namespace ndn {
+namespace delorean {
 
 typedef uint64_t Timestamp;
 
-} // namespace nsl
+} // namespace delorean
+} // namespace ndn
 
 #endif // NDN_DELOREAN_UTIL_TIMESTAMP_HPP