diff --git a/helper/ccnb-parser/syntax-tree/ccnb-parser-ext.cc b/helper/ccnb-parser/syntax-tree/ccnb-parser-ext.cc
new file mode 100644
index 0000000..7d90019
--- /dev/null
+++ b/helper/ccnb-parser/syntax-tree/ccnb-parser-ext.cc
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnb-parser-ext.h"
+
+namespace ns3 {
+namespace CcnbParser {
+
+Ext::Ext (Buffer::Iterator &start, uint32_t extSubtype)
+{
+  m_extSubtype = extSubtype;
+}
+
+}
+}