diff --git a/src/util/rtt-estimator.hpp b/src/util/rtt-estimator.hpp
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (C) 2016-2018, Arizona Board of Regents.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library 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 Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ *
+ * @author Shuo Yang
+ * @author Weiwei Liu
+ * @author Chavoosh Ghasemi
+ */
+
+#ifndef NDN_CXX_UTIL_RTT_ESTIMATOR_HPP
+#define NDN_CXX_UTIL_RTT_ESTIMATOR_HPP
+
+#include "../common.hpp"
+#include "signal.hpp"
+#include "time.hpp"
+
+namespace ndn {
+namespace util {
+
+/**
+ * @brief RTT Estimator.
+ *
+ * This class implements the "Mean-Deviation" RTT estimator, as discussed in RFC 6298,
+ * with the modifications to RTO calculation described in RFC 7323 Appendix G.
+ */
+class RttEstimator
+{
+public:
+  using MillisecondsDouble = time::duration<double, time::milliseconds::period>;
+
+public:
+  class Options
+  {
+  public:
+    constexpr
+    Options() noexcept
+    {
+    }
+
+  public:
+    double alpha = 0.125; ///< weight of exponential moving average for meanRtt
+    double beta = 0.25; ///< weight of exponential moving average for varRtt
+    int k = 4; ///< factor of RTT variation when calculating RTO
+    MillisecondsDouble initialRto = MillisecondsDouble(1000.0); ///< initial RTO value
+    MillisecondsDouble minRto = MillisecondsDouble(200.0); ///< lower bound of RTO
+    MillisecondsDouble maxRto = MillisecondsDouble(20000.0); ///< upper bound of RTO
+    int rtoBackoffMultiplier = 2;
+  };
+
+  /**
+   * @brief Create a RTT Estimator
+   *
+   * Configures the RTT Estimator with the default parameters if an instance of Options
+   * is not passed to the constructor.
+   */
+  explicit
+  RttEstimator(const Options& options = Options());
+
+  /**
+   * @brief Add a new RTT measurement to the estimator.
+   *
+   * @param rtt the sampled rtt
+   * @param nExpectedSamples number of expected samples, must be greater than 0.
+   *        It should be set to current number of in-flight Interests. Please
+   *        refer to Appendix G of RFC 7323 for details.
+   * @note Don't add RTT measurements for retransmissions
+   */
+  void
+  addMeasurement(MillisecondsDouble rtt, size_t nExpectedSamples);
+
+  /**
+   * @brief Returns the estimated RTO value
+   */
+  MillisecondsDouble
+  getEstimatedRto() const
+  {
+    return m_rto;
+  }
+
+  /**
+   * @brief Returns the minimum RTT observed
+   */
+  MillisecondsDouble
+  getMinRtt() const
+  {
+    return m_rttMin;
+  }
+
+  /**
+   * @brief Returns the maximum RTT observed
+   */
+  MillisecondsDouble
+  getMaxRtt() const
+  {
+    return m_rttMax;
+  }
+
+  /**
+   * @brief Returns the average RTT
+   */
+  MillisecondsDouble
+  getAvgRtt() const
+  {
+    return m_rttAvg;
+  }
+
+  /**
+   * @brief Backoff RTO by a factor of Options::rtoBackoffMultiplier
+   */
+  void
+  backoffRto();
+
+private:
+  const Options m_options;
+  MillisecondsDouble m_sRtt; ///< smoothed round-trip time
+  MillisecondsDouble m_rttVar; ///< round-trip time variation
+  MillisecondsDouble m_rto; ///< retransmission timeout
+  MillisecondsDouble m_rttMin;
+  MillisecondsDouble m_rttMax;
+  MillisecondsDouble m_rttAvg;
+  int64_t m_nRttSamples; ///< number of RTT samples
+};
+
+} // namespace util
+} // namespace ndn
+
+#endif // NDN_CXX_UTIL_RTT_ESTIMATOR_HPP