diff --git a/core/interval-generator.hpp b/core/interval-generator.hpp
new file mode 100644
index 0000000..6e617cf
--- /dev/null
+++ b/core/interval-generator.hpp
@@ -0,0 +1,47 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2016, Regents of the University of California.
+ *
+ * This file is part of ChronoShare, a decentralized file sharing application over NDN.
+ *
+ * ChronoShare is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * ChronoShare 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 copies of the GNU General Public License along with
+ * ChronoShare, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ChronoShare authors and contributors.
+ */
+
+#ifndef CHRONOSHARE_CORE_INTERVAL_GENERATOR_HPP
+#define CHRONOSHARE_CORE_INTERVAL_GENERATOR_HPP
+
+#include "chronoshare-common.hpp"
+
+namespace ndn {
+namespace chronoshare {
+
+class IntervalGenerator;
+typedef shared_ptr<IntervalGenerator> IntervalGeneratorPtr;
+
+class IntervalGenerator
+{
+public:
+  virtual
+  ~IntervalGenerator()
+  {
+  }
+
+  virtual double
+  nextInterval() = 0;
+};
+
+} // chronoshare
+} // ndn
+
+#endif // CHRONOSHARE_CORE_INTERVAL_GENERATOR_HPP