diff --git a/ndnboost/mpl/always.hpp b/ndnboost/mpl/always.hpp
new file mode 100644
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+++ b/ndnboost/mpl/always.hpp
@@ -0,0 +1,39 @@
+
+#ifndef BOOST_MPL_ALWAYS_HPP_INCLUDED
+#define BOOST_MPL_ALWAYS_HPP_INCLUDED
+
+// Copyright Aleksey Gurtovoy 2001-2004
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Id: always.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
+// $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $
+// $Revision: 49267 $
+
+#include <ndnboost/mpl/aux_/preprocessor/def_params_tail.hpp>
+#include <ndnboost/mpl/aux_/na.hpp>
+#include <ndnboost/mpl/aux_/arity_spec.hpp>
+
+namespace ndnboost { namespace mpl {
+
+template< typename Value > struct always
+{
+    template<
+          typename T
+        BOOST_MPL_PP_NESTED_DEF_PARAMS_TAIL(1, typename T, na)
+        >
+    struct apply
+    {
+        typedef Value type;
+    };
+};
+
+BOOST_MPL_AUX_ARITY_SPEC(1, always)
+
+}}
+
+#endif // BOOST_MPL_ALWAYS_HPP_INCLUDED