diff --git a/daemon/fw/rtt-estimator.cpp b/daemon/fw/rtt-estimator.cpp
new file mode 100644
index 0000000..97b2ab0
--- /dev/null
+++ b/daemon/fw/rtt-estimator.cpp
@@ -0,0 +1,79 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014  Regents of the University of California,
+ *                     Arizona Board of Regents,
+ *                     Colorado State University,
+ *                     University Pierre & Marie Curie, Sorbonne University,
+ *                     Washington University in St. Louis,
+ *                     Beijing Institute of Technology,
+ *                     The University of Memphis
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD 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.
+ *
+ * NFD 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
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#include "rtt-estimator.hpp"
+
+namespace nfd {
+
+RttEstimator::RttEstimator(uint16_t maxMultiplier, Duration minRto, double gain)
+  : m_maxMultiplier(maxMultiplier)
+  , m_minRto(minRto.count())
+  , m_rtt(RttEstimator::getInitialRtt().count())
+  , m_gain(gain)
+  , m_variance(0)
+  , m_multiplier(1)
+  , m_nSamples(0)
+{
+}
+
+void
+RttEstimator::addMeasurement(Duration measure)
+{
+  double m = static_cast<double>(measure.count());
+  if (m_nSamples > 0) {
+    double err = m - m_rtt;
+    double gErr = err * m_gain;
+    m_rtt += gErr;
+    double difference = std::abs(err) - m_variance;
+    m_variance += difference * m_gain;
+  } else {
+    m_rtt = m;
+    m_variance = m;
+  }
+  ++m_nSamples;
+  m_multiplier = 1;
+}
+
+void
+RttEstimator::incrementMultiplier()
+{
+  m_multiplier = std::min(static_cast<uint16_t>(m_multiplier + 1), m_maxMultiplier);
+}
+
+void
+RttEstimator::doubleMultiplier()
+{
+  m_multiplier = std::min(static_cast<uint16_t>(m_multiplier * 2), m_maxMultiplier);
+}
+
+RttEstimator::Duration
+RttEstimator::computeRto() const
+{
+  double rto = std::max(m_minRto, m_rtt + 4 * m_variance);
+  rto *= m_multiplier;
+  return Duration(static_cast<Duration::rep>(rto));
+}
+
+} // namespace nfd
diff --git a/daemon/fw/rtt-estimator.hpp b/daemon/fw/rtt-estimator.hpp
new file mode 100644
index 0000000..a830c5a
--- /dev/null
+++ b/daemon/fw/rtt-estimator.hpp
@@ -0,0 +1,83 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014  Regents of the University of California,
+ *                     Arizona Board of Regents,
+ *                     Colorado State University,
+ *                     University Pierre & Marie Curie, Sorbonne University,
+ *                     Washington University in St. Louis,
+ *                     Beijing Institute of Technology,
+ *                     The University of Memphis
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD 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.
+ *
+ * NFD 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
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#ifndef NFD_DAEMON_FW_RTT_ESTIMATOR_HPP
+#define NFD_DAEMON_FW_RTT_ESTIMATOR_HPP
+
+#include "common.hpp"
+
+namespace nfd {
+
+/**
+ * \brief implements the Mean-Deviation RTT estimator
+ *
+ * reference: ns3::RttMeanDeviation
+ *
+ * This RttEstimator algorithm is designed for TCP, which is a continuous stream.
+ * NDN Interest-Data traffic is not always a continuous stream,
+ * so NDN may need a different RttEstimator.
+ * The design of a more suitable RttEstimator is a research question.
+ */
+class RttEstimator
+{
+public:
+  typedef time::microseconds Duration;
+
+  static Duration
+  getInitialRtt(void)
+  {
+    return time::seconds(1);
+  }
+
+  RttEstimator(uint16_t maxMultiplier = 16,
+               Duration minRto = time::milliseconds(1),
+               double gain = 0.1);
+
+  void
+  addMeasurement(Duration measure);
+
+  void
+  incrementMultiplier();
+
+  void
+  doubleMultiplier();
+
+  Duration
+  computeRto() const;
+
+private:
+  uint16_t m_maxMultiplier;
+  double m_minRto;
+
+  double m_rtt;
+  double m_gain;
+  double m_variance;
+  uint16_t m_multiplier;
+  uint32_t m_nSamples;
+};
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_FW_RTT_ESTIMATOR_HPP