11 files changed, 592 insertions, 330 deletions

diff --git a/libtransport/src/protocols/CMakeLists.txt b/libtransport/src/protocols/CMakeLists.txt
index 8bfbdd6ad..02e626840 100644
--- a/libtransport/src/protocols/CMakeLists.txt
+++ b/libtransport/src/protocols/CMakeLists.txt
@@ -32,6 +32,8 @@ list(APPEND HEADER_FILES
   ${CMAKE_CURRENT_SOURCE_DIR}/errors.h
   ${CMAKE_CURRENT_SOURCE_DIR}/verification_manager.h
   ${CMAKE_CURRENT_SOURCE_DIR}/data_processing_events.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/raaqm_transport_algorithm.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/transport_algorithm.h
 )
 
 list(APPEND SOURCE_FILES
@@ -50,6 +52,8 @@ list(APPEND SOURCE_FILES
   ${CMAKE_CURRENT_SOURCE_DIR}/rtc_data_path.cc
   ${CMAKE_CURRENT_SOURCE_DIR}/errors.cc
   ${CMAKE_CURRENT_SOURCE_DIR}/verification_manager.cc
+  ${CMAKE_CURRENT_SOURCE_DIR}/raaqm_transport_algorithm.cc
+  ${CMAKE_CURRENT_SOURCE_DIR}/transport_algorithm.cc
 )
 
 set(RAAQM_CONFIG_INSTALL_PREFIX
diff --git a/libtransport/src/protocols/cbr.cc b/libtransport/src/protocols/cbr.cc
index 0bffd7d18..fc8b53b8d 100644
--- a/libtransport/src/protocols/cbr.cc
+++ b/libtransport/src/protocols/cbr.cc
@@ -34,18 +34,6 @@ void CbrTransportProtocol::reset() {
                            current_window_size_);
 }
 
-void CbrTransportProtocol::afterDataUnsatisfied(uint64_t segment) {}
-
-void CbrTransportProtocol::afterContentReception(
-    const Interest &interest, const ContentObject &content_object) {
-  auto segment = content_object.getName().getSuffix();
-  auto now = utils::SteadyClock::now();
-  auto rtt = std::chrono::duration_cast<utils::Microseconds>(
-      now - interest_timepoints_[segment & mask]);
-  // Update stats
-  updateStats(segment, rtt.count(), now);
-}
-
 }  // end namespace protocol
 
 }  // end namespace transport
diff --git a/libtransport/src/protocols/cbr.h b/libtransport/src/protocols/cbr.h
index 20129f6a3..32788cd05 100644
--- a/libtransport/src/protocols/cbr.h
+++ b/libtransport/src/protocols/cbr.h
@@ -28,11 +28,6 @@ class CbrTransportProtocol : public RaaqmTransportProtocol {
   int start() override;
 
   void reset() override;
-
- private:
-  void afterContentReception(const Interest &interest,
-                             const ContentObject &content_object) override;
-  void afterDataUnsatisfied(uint64_t segment) override;
 };
 
 }  // end namespace protocol
diff --git a/libtransport/src/protocols/raaqm.cc b/libtransport/src/protocols/raaqm.cc
index 783d6194b..cdf878328 100644
--- a/libtransport/src/protocols/raaqm.cc
+++ b/libtransport/src/protocols/raaqm.cc
@@ -32,39 +32,36 @@ RaaqmTransportProtocol::RaaqmTransportProtocol(
     implementation::ConsumerSocket *icn_socket)
     : TransportProtocol(icn_socket, new ByteStreamReassembly(icn_socket, this)),
       current_window_size_(1),
-      interests_in_flight_(0),
-      cur_path_(nullptr),
+      raaqm_algorithm_(nullptr),
       t0_(utils::SteadyClock::now()),
-      rate_estimator_(nullptr),
       schedule_interests_(true) {
   init();
 }
 
-RaaqmTransportProtocol::~RaaqmTransportProtocol() {
-  if (rate_estimator_) {
-    delete rate_estimator_;
-  }
-}
+RaaqmTransportProtocol::~RaaqmTransportProtocol() {}
 
 int RaaqmTransportProtocol::start() {
-  if (rate_estimator_) {
-    rate_estimator_->onStart();
-  }
-
-  if (!cur_path_) {
+  if (!raaqm_algorithm_) {
     // RAAQM
     double drop_factor;
     double minimum_drop_probability;
     uint32_t sample_number;
     uint32_t interest_lifetime;
+    double gamma = 0., max_window = 0., min_window = 0., beta;
 
     socket_->getSocketOption(RaaqmTransportOptions::DROP_FACTOR, drop_factor);
+    socket_->getSocketOption(RaaqmTransportOptions::GAMMA_VALUE, gamma);
+    socket_->getSocketOption(RaaqmTransportOptions::BETA_VALUE, beta);
     socket_->getSocketOption(RaaqmTransportOptions::MINIMUM_DROP_PROBABILITY,
                              minimum_drop_probability);
     socket_->getSocketOption(RaaqmTransportOptions::SAMPLE_NUMBER,
                              sample_number);
     socket_->getSocketOption(GeneralTransportOptions::INTEREST_LIFETIME,
                              interest_lifetime);
+    socket_->getSocketOption(GeneralTransportOptions::MAX_WINDOW_SIZE,
+                             max_window);
+    socket_->getSocketOption(GeneralTransportOptions::MIN_WINDOW_SIZE,
+                             min_window);
 
     // Rate Estimation
     double alpha = 0.0;
@@ -78,20 +75,19 @@ int RaaqmTransportProtocol::start() {
                              choice_param);
 
     if (choice_param == 1) {
-      rate_estimator_ = new ALaTcpEstimator();
+      rate_estimator_ = std::make_unique<ALaTcpEstimator>();
     } else {
-      rate_estimator_ = new SimpleEstimator(alpha, batching_param);
+      rate_estimator_ =
+          std::make_unique<SimpleEstimator>(alpha, batching_param);
     }
 
     socket_->getSocketOption(RateEstimationOptions::RATE_ESTIMATION_OBSERVER,
                              &rate_estimator_->observer_);
 
-    // Current path
-    auto cur_path = std::make_unique<RaaqmDataPath>(
-        drop_factor, minimum_drop_probability, interest_lifetime * 1000,
-        sample_number);
-    cur_path_ = cur_path.get();
-    path_table_[default_values::path_id] = std::move(cur_path);
+    raaqm_algorithm_ = std::make_unique<RaaqmTransportAlgorithm>(
+        stats_, rate_estimator_.get(), drop_factor, minimum_drop_probability,
+        gamma, beta, sample_number, interest_lifetime, beta_wifi_, drop_wifi_,
+        beta_lte_, drop_lte_, wifi_delay_, lte_delay_, max_window, min_window);
   }
 
   portal_->setConsumerCallback(this);
@@ -109,6 +105,7 @@ void RaaqmTransportProtocol::reset() {
   std::queue<Interest::Ptr> empty;
   std::swap(interest_to_retransmit_, empty);
   stats_->reset();
+  raaqm_algorithm_->reset();
 
   // Reset reassembly component
   reassembly_protocol_->reInitialize();
@@ -122,65 +119,13 @@ bool RaaqmTransportProtocol::verifyKeyPackets() {
   return index_manager_->onKeyToVerify();
 }
 
-void RaaqmTransportProtocol::increaseWindow() {
-  // return;
-  double max_window_size = 0.;
-  socket_->getSocketOption(GeneralTransportOptions::MAX_WINDOW_SIZE,
-                           max_window_size);
-  if (current_window_size_ < max_window_size) {
-    double gamma = 0.;
-    socket_->getSocketOption(RaaqmTransportOptions::GAMMA_VALUE, gamma);
-
-    current_window_size_ += gamma / current_window_size_;
-    socket_->setSocketOption(GeneralTransportOptions::CURRENT_WINDOW_SIZE,
-                             current_window_size_);
-  }
-  rate_estimator_->onWindowIncrease(current_window_size_);
-}
-
-void RaaqmTransportProtocol::decreaseWindow() {
-  // return;
-  double min_window_size = 0.;
-  socket_->getSocketOption(GeneralTransportOptions::MIN_WINDOW_SIZE,
-                           min_window_size);
-  if (current_window_size_ > min_window_size) {
-    double beta = 0.;
-    socket_->getSocketOption(RaaqmTransportOptions::BETA_VALUE, beta);
-
-    current_window_size_ = current_window_size_ * beta;
-    if (current_window_size_ < min_window_size) {
-      current_window_size_ = min_window_size;
-    }
-
-    socket_->setSocketOption(GeneralTransportOptions::CURRENT_WINDOW_SIZE,
-                             current_window_size_);
-  }
-  rate_estimator_->onWindowDecrease(current_window_size_);
-}
-
-void RaaqmTransportProtocol::afterDataUnsatisfied(uint64_t segment) {
-  // Decrease the window because the timeout happened
-  decreaseWindow();
-}
-
-void RaaqmTransportProtocol::afterContentReception(
-    const Interest &interest, const ContentObject &content_object) {
-  updatePathTable(content_object);
-  increaseWindow();
-  updateRtt(interest.getName().getSuffix());
-  rate_estimator_->onDataReceived((int)content_object.payloadSize() +
-                                  (int)content_object.headerSize());
-  // Set drop probablility and window size accordingly
-  RAAQM();
-}
-
 void RaaqmTransportProtocol::init() {
   std::ifstream is(RAAQM_CONFIG_PATH);
 
   std::string line;
   raaqm_autotune_ = false;
-  default_beta_ = default_values::beta_value;
-  default_drop_ = default_values::drop_factor;
+  double default_beta = default_values::beta_value;
+  double default_drop = default_values::drop_factor;
   beta_wifi_ = default_values::beta_value;
   drop_wifi_ = default_values::drop_factor;
   beta_lte_ = default_values::beta_value;
@@ -236,17 +181,16 @@ void RaaqmTransportProtocol::init() {
 
     if (command == "beta") {
       std::string tmp;
-      line_s >> tmp >> default_beta_;
-      socket_->setSocketOption(RaaqmTransportOptions::BETA_VALUE,
-                               default_beta_);
+      line_s >> tmp >> default_beta;
+      socket_->setSocketOption(RaaqmTransportOptions::BETA_VALUE, default_beta);
       continue;
     }
 
     if (command == "drop") {
       std::string tmp;
-      line_s >> tmp >> default_drop_;
+      line_s >> tmp >> default_drop;
       socket_->setSocketOption(RaaqmTransportOptions::DROP_FACTOR,
-                               default_drop_);
+                               default_drop);
       continue;
     }
 
@@ -285,6 +229,7 @@ void RaaqmTransportProtocol::init() {
       line_s >> tmp >> lte_delay_;
       continue;
     }
+
     if (command == "alpha") {
       std::string tmp;
       double rate_alpha = 0.0;
@@ -343,14 +288,27 @@ void RaaqmTransportProtocol::onContentObject(
 
 void RaaqmTransportProtocol::onContentSegment(
     Interest::Ptr &&interest, ContentObject::Ptr &&content_object) {
-  uint32_t incremental_suffix = content_object->getName().getSuffix();
+  uint32_t suffix = content_object->getName().getSuffix();
 
   // Decrease in-flight interests
   interests_in_flight_--;
 
-  // Update stats
-  if (!interest_retransmissions_[incremental_suffix & mask]) {
-    afterContentReception(*interest, *content_object);
+  // Get new value for the window
+  current_window_size_ =
+      raaqm_algorithm_->onContentObject(suffix, content_object->getPathLabel());
+
+  // Print stats if needed
+  if (*stats_summary_) {
+    auto now = std::chrono::steady_clock::now();
+    auto dt = std::chrono::duration_cast<utils::Milliseconds>(now - t0_);
+
+    uint32_t timer_interval_milliseconds = 0;
+    socket_->getSocketOption(GeneralTransportOptions::STATS_INTERVAL,
+                             timer_interval_milliseconds);
+    if (dt.count() > timer_interval_milliseconds) {
+      (*stats_summary_)(*socket_->getInterface(), *stats_);
+      t0_ = now;
+    }
   }
 
   index_manager_->onContentObject(std::move(interest),
@@ -396,8 +354,6 @@ void RaaqmTransportProtocol::onReassemblyFailed(std::uint32_t missing_segment) {
 }
 
 void RaaqmTransportProtocol::onTimeout(Interest::Ptr &&interest) {
-  checkForStalePaths();
-
   const Name &n = interest->getName();
 
   TRANSPORT_LOGW("Timeout on content %s", n.toString().c_str());
@@ -419,8 +375,6 @@ void RaaqmTransportProtocol::onTimeout(Interest::Ptr &&interest) {
     (*on_interest_timeout_)(*socket_->getInterface(), *interest);
   }
 
-  afterDataUnsatisfied(segment);
-
   uint32_t max_rtx = 0;
   socket_->getSocketOption(GeneralTransportOptions::MAX_INTEREST_RETX, max_rtx);
 
@@ -502,7 +456,6 @@ bool RaaqmTransportProtocol::sendInterest(std::uint64_t next_suffix) {
   // This is set to ~0 so that the next interest_retransmissions_ + 1,
   // performed by sendInterest, will result in 0
   interest_retransmissions_[next_suffix & mask] = ~0;
-  interest_timepoints_[next_suffix & mask] = utils::SteadyClock::now();
 
   sendInterest(std::move(interest));
 
@@ -518,168 +471,10 @@ void RaaqmTransportProtocol::sendInterest(Interest::Ptr &&interest) {
 }
 
 void RaaqmTransportProtocol::onContentReassembled(std::error_code ec) {
-  rate_estimator_->onDownloadFinished();
   TransportProtocol::onContentReassembled(ec);
   schedule_interests_ = false;
 }
 
-void RaaqmTransportProtocol::updateRtt(uint64_t segment) {
-  if (TRANSPORT_EXPECT_FALSE(!cur_path_)) {
-    throw std::runtime_error("RAAQM ERROR: no current path found, exit");
-  } else {
-    auto now = utils::SteadyClock::now();
-    utils::Microseconds rtt = std::chrono::duration_cast<utils::Microseconds>(
-        now - interest_timepoints_[segment & mask]);
-
-    // Update stats
-    updateStats((uint32_t)segment, rtt.count(), now);
-
-    if (rate_estimator_) {
-      rate_estimator_->onRttUpdate((double)rtt.count());
-    }
-
-    cur_path_->insertNewRtt(rtt.count(), now);
-    cur_path_->smoothTimer();
-
-    if (cur_path_->newPropagationDelayAvailable()) {
-      checkDropProbability();
-    }
-  }
-}
-
-void RaaqmTransportProtocol::RAAQM() {
-  if (!cur_path_) {
-    throw errors::RuntimeException("ERROR: no current path found, exit");
-    exit(EXIT_FAILURE);
-  } else {
-    // Change drop probability according to RTT statistics
-    cur_path_->updateDropProb();
-
-    double coin = ((double)rand() / (RAND_MAX));
-    if (coin <= cur_path_->getDropProb()) {
-      decreaseWindow();
-    }
-  }
-}
-
-void RaaqmTransportProtocol::updateStats(uint32_t suffix, uint64_t rtt,
-                                         utils::TimePoint &now) {
-  // Update RTT statistics
-  stats_->updateAverageRtt(rtt);
-  stats_->updateAverageWindowSize(current_window_size_);
-
-  // Call statistics callback
-  if (*stats_summary_) {
-    auto dt = std::chrono::duration_cast<utils::Milliseconds>(now - t0_);
-
-    uint32_t timer_interval_milliseconds = 0;
-    socket_->getSocketOption(GeneralTransportOptions::STATS_INTERVAL,
-                             timer_interval_milliseconds);
-    if (dt.count() > timer_interval_milliseconds) {
-      (*stats_summary_)(*socket_->getInterface(), *stats_);
-      t0_ = now;
-    }
-  }
-}
-
-void RaaqmTransportProtocol::updatePathTable(
-    const ContentObject &content_object) {
-  uint32_t path_id = content_object.getPathLabel();
-
-  if (path_table_.find(path_id) == path_table_.end()) {
-    if (TRANSPORT_EXPECT_TRUE(cur_path_ != nullptr)) {
-      // Create a new path with some default param
-
-      if (TRANSPORT_EXPECT_FALSE(path_table_.empty())) {
-        throw errors::RuntimeException(
-            "[RAAQM] No path initialized for path table, error could be in "
-            "default path initialization.");
-      }
-
-      // Initiate the new path default param
-      auto new_path = std::make_unique<RaaqmDataPath>(
-          *(path_table_.at(default_values::path_id)));
-
-      // Insert the new path into hash table
-      path_table_[path_id] = std::move(new_path);
-    } else {
-      throw errors::RuntimeException(
-          "UNEXPECTED ERROR: when running,current path not found.");
-    }
-  }
-
-  cur_path_ = path_table_[path_id].get();
-
-  size_t header_size = content_object.headerSize();
-  size_t data_size = content_object.payloadSize();
-
-  // Update measurements for path
-  cur_path_->updateReceivedStats(header_size + data_size, data_size);
-}
-
-void RaaqmTransportProtocol::checkDropProbability() {
-  if (!raaqm_autotune_) {
-    return;
-  }
-
-  unsigned int max_pd = 0;
-  PathTable::iterator it;
-  for (auto it = path_table_.begin(); it != path_table_.end(); ++it) {
-    if (it->second->getPropagationDelay() > max_pd &&
-        it->second->getPropagationDelay() != UINT_MAX &&
-        !it->second->isStale()) {
-      max_pd = it->second->getPropagationDelay();
-    }
-  }
-
-  double drop_prob = 0;
-  double beta = 0;
-  if (max_pd < wifi_delay_) {  // only ethernet paths
-    drop_prob = default_drop_;
-    beta = default_beta_;
-  } else if (max_pd < lte_delay_) {  // at least one wifi path
-    drop_prob = drop_wifi_;
-    beta = beta_wifi_;
-  } else {  // at least one lte path
-    drop_prob = drop_lte_;
-    beta = beta_lte_;
-  }
-
-  double old_drop_prob = 0;
-  double old_beta = 0;
-  socket_->getSocketOption(RaaqmTransportOptions::BETA_VALUE, old_beta);
-  socket_->getSocketOption(RaaqmTransportOptions::DROP_FACTOR, old_drop_prob);
-
-  if (drop_prob == old_drop_prob && beta == old_beta) {
-    return;
-  }
-
-  socket_->setSocketOption(RaaqmTransportOptions::BETA_VALUE, beta);
-  socket_->setSocketOption(RaaqmTransportOptions::DROP_FACTOR, drop_prob);
-
-  for (it = path_table_.begin(); it != path_table_.end(); it++) {
-    it->second->setDropProb(drop_prob);
-  }
-}
-
-void RaaqmTransportProtocol::checkForStalePaths() {
-  if (!raaqm_autotune_) {
-    return;
-  }
-
-  bool stale = false;
-  PathTable::iterator it;
-  for (it = path_table_.begin(); it != path_table_.end(); ++it) {
-    if (it->second->isStale()) {
-      stale = true;
-      break;
-    }
-  }
-  if (stale) {
-    checkDropProbability();
-  }
-}
-
 }  // end namespace protocol
 
 }  // namespace transport
diff --git a/libtransport/src/protocols/raaqm.h b/libtransport/src/protocols/raaqm.h
index fce4194d4..2999b50cf 100644
--- a/libtransport/src/protocols/raaqm.h
+++ b/libtransport/src/protocols/raaqm.h
@@ -20,6 +20,7 @@
 #include <protocols/congestion_window_protocol.h>
 #include <protocols/protocol.h>
 #include <protocols/raaqm_data_path.h>
+#include <protocols/raaqm_transport_algorithm.h>
 #include <protocols/rate_estimation.h>
 
 #include <queue>
@@ -29,8 +30,7 @@ namespace transport {
 
 namespace protocol {
 
-class RaaqmTransportProtocol : public TransportProtocol,
-                               public CWindowProtocol {
+class RaaqmTransportProtocol : public TransportProtocol {
  public:
   RaaqmTransportProtocol(implementation::ConsumerSocket *icnet_socket);
 
@@ -51,16 +51,6 @@ class RaaqmTransportProtocol : public TransportProtocol,
   using PathTable =
       std::unordered_map<uint32_t, std::unique_ptr<RaaqmDataPath>>;
 
-  void increaseWindow() override;
-  void decreaseWindow() override;
-
-  virtual void afterContentReception(const Interest &interest,
-                                     const ContentObject &content_object);
-  virtual void afterDataUnsatisfied(uint64_t segment);
-
-  virtual void updateStats(uint32_t suffix, uint64_t rtt,
-                           utils::TimePoint &now);
-
  private:
   void init();
 
@@ -86,48 +76,21 @@ class RaaqmTransportProtocol : public TransportProtocol,
 
   void updateRtt(uint64_t segment);
 
-  void RAAQM();
-
-  void updatePathTable(const ContentObject &content_object);
-
-  void checkDropProbability();
-
-  void checkForStalePaths();
-
-  void printRtt();
-
  protected:
-  // Congestion window management
-  double current_window_size_;
-  // Protocol management
-  uint64_t interests_in_flight_;
-  std::array<std::uint32_t, buffer_size> interest_retransmissions_;
-  std::array<utils::TimePoint, buffer_size> interest_timepoints_;
   std::queue<Interest::Ptr> interest_to_retransmit_;
+  std::array<std::uint32_t, buffer_size> interest_retransmissions_;
+  uint32_t interests_in_flight_;
+  double current_window_size_;
 
  private:
-  /**
-   * Current download path
-   */
-  RaaqmDataPath *cur_path_;
-
-  /**
-   * Hash table for path: each entry is a pair path ID(key) - path object
-   */
-  PathTable path_table_;
-
+  std::unique_ptr<TransportAlgorithm> raaqm_algorithm_;
+  std::unique_ptr<IcnRateEstimator> rate_estimator_;
   // TimePoints for statistic
   utils::TimePoint t0_;
 
-  bool set_interest_filter_;
-
-  // for rate-estimation at packet level
-  IcnRateEstimator *rate_estimator_;
-
-  // params for autotuning
+  // Temporary placeholder for RAAQM algorithm
+  // parameters
   bool raaqm_autotune_;
-  double default_beta_;
-  double default_drop_;
   double beta_wifi_;
   double drop_wifi_;
   double beta_lte_;
diff --git a/libtransport/src/protocols/raaqm_data_path.cc b/libtransport/src/protocols/raaqm_data_path.cc
index 8bbbadcf2..499b579f3 100644
--- a/libtransport/src/protocols/raaqm_data_path.cc
+++ b/libtransport/src/protocols/raaqm_data_path.cc
@@ -14,7 +14,6 @@
  */
 
 #include <hicn/transport/utils/chrono_typedefs.h>
-
 #include <protocols/raaqm_data_path.h>
 
 namespace transport {
@@ -66,15 +65,6 @@ RaaqmDataPath &RaaqmDataPath::insertNewRtt(uint64_t new_rtt,
   return *this;
 }
 
-RaaqmDataPath &RaaqmDataPath::updateReceivedStats(std::size_t packet_size,
-                                                  std::size_t data_size) {
-  packets_received_++;
-  m_packets_bytes_received_ += packet_size;
-  raw_data_bytes_received_ += data_size;
-
-  return *this;
-}
-
 double RaaqmDataPath::getDropFactor() { return drop_factor_; }
 
 double RaaqmDataPath::getDropProb() { return drop_prob_; }
diff --git a/libtransport/src/protocols/raaqm_data_path.h b/libtransport/src/protocols/raaqm_data_path.h
index 3f037bc76..d1234e743 100644
--- a/libtransport/src/protocols/raaqm_data_path.h
+++ b/libtransport/src/protocols/raaqm_data_path.h
@@ -16,7 +16,6 @@
 #pragma once
 
 #include <hicn/transport/utils/chrono_typedefs.h>
-
 #include <utils/min_filter.h>
 
 #include <chrono>
@@ -48,15 +47,6 @@ class RaaqmDataPath {
   RaaqmDataPath &insertNewRtt(uint64_t new_rtt, const utils::TimePoint &now);
 
   /**
-   * @brief Update the path statistics
-   * @param packet_size the size of the packet received, including the ICN
-   * header
-   * @param data_size the size of the data received, without the ICN header
-   */
-  RaaqmDataPath &updateReceivedStats(std::size_t packet_size,
-                                     std::size_t data_size);
-
-  /**
    * @brief Get the value of the drop factor parameter
    */
   double getDropFactor();
diff --git a/libtransport/src/protocols/raaqm_transport_algorithm.cc b/libtransport/src/protocols/raaqm_transport_algorithm.cc
new file mode 100644
index 000000000..09e3a47ab
--- /dev/null
+++ b/libtransport/src/protocols/raaqm_transport_algorithm.cc
@@ -0,0 +1,255 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <protocols/raaqm_transport_algorithm.h>
+
+namespace transport {
+namespace protocol {
+
+RaaqmTransportAlgorithm::RaaqmTransportAlgorithm(
+    interface::TransportStatistics *stats, IcnRateEstimator *rate_estimator,
+    double drop_factor, double minimum_drop_probability, double gamma,
+    double beta, uint32_t sample_number, uint32_t interest_lifetime,
+    double beta_wifi, double drop_wifi, double beta_lte, double drop_lte,
+    unsigned int wifi_delay, unsigned int lte_delay, double max_window,
+    double min_window)
+    : current_window_size_(1),
+      cur_path_(nullptr),
+      rate_estimator_(rate_estimator),
+      stats_(stats),
+      drop_factor_(drop_factor),
+      minimum_drop_probability_(minimum_drop_probability),
+      gamma_(gamma),
+      beta_(beta),
+      sample_number_(sample_number),
+      interest_lifetime_(interest_lifetime),
+      beta_wifi_(beta_wifi),
+      drop_wifi_(drop_wifi),
+      beta_lte_(beta_lte),
+      drop_lte_(drop_lte),
+      wifi_delay_(wifi_delay),
+      lte_delay_(lte_delay),
+      max_window_(max_window),
+      min_window_(min_window) {}
+
+RaaqmTransportAlgorithm::~RaaqmTransportAlgorithm() {}
+
+void RaaqmTransportAlgorithm::reset() {
+  if (rate_estimator_) {
+    rate_estimator_->onStart();
+  }
+
+  if (!cur_path_) {
+    // Current path
+    auto cur_path = std::make_unique<RaaqmDataPath>(
+        drop_factor_, minimum_drop_probability_, interest_lifetime_ * 1000,
+        sample_number_);
+    cur_path_ = cur_path.get();
+    path_table_[interface::default_values::path_id] = std::move(cur_path);
+  }
+}
+
+void RaaqmTransportAlgorithm::increaseWindow() {
+  if (current_window_size_ < max_window_) {
+    current_window_size_ += gamma_ / current_window_size_;
+  }
+
+  if (rate_estimator_) {
+    rate_estimator_->onWindowIncrease(current_window_size_);
+  }
+}
+
+void RaaqmTransportAlgorithm::decreaseWindow() {
+  if (current_window_size_ > min_window_) {
+    current_window_size_ = current_window_size_ * beta_;
+    if (current_window_size_ < min_window_) {
+      current_window_size_ = min_window_;
+    }
+  }
+
+  if (rate_estimator_) {
+    rate_estimator_->onWindowDecrease(current_window_size_);
+  }
+}
+
+void RaaqmTransportAlgorithm::updateRtt(uint32_t suffix) {
+  if (TRANSPORT_EXPECT_FALSE(!cur_path_)) {
+    throw std::runtime_error("RAAQM ERROR: no current path found, exit");
+  } else {
+    auto now = utils::SteadyClock::now();
+    utils::Microseconds rtt = std::chrono::duration_cast<utils::Microseconds>(
+        now - interest_timepoints_[suffix & mask]);
+
+    updateStats(suffix, rtt.count(), now);
+
+    if (rate_estimator_) {
+      rate_estimator_->onRttUpdate((double)rtt.count());
+    }
+
+    cur_path_->insertNewRtt(rtt.count(), now);
+    cur_path_->smoothTimer();
+
+    if (cur_path_->newPropagationDelayAvailable()) {
+      checkDropProbability();
+    }
+  }
+}
+
+void RaaqmTransportAlgorithm::RAAQM() {
+  if (!cur_path_) {
+    throw errors::RuntimeException("ERROR: no current path found, exit");
+    exit(EXIT_FAILURE);
+  } else {
+    // Change drop probability according to RTT statistics
+    cur_path_->updateDropProb();
+
+    double coin = ((double)rand() / (RAND_MAX));
+    if (coin <= cur_path_->getDropProb()) {
+      decreaseWindow();
+    }
+  }
+}
+
+void RaaqmTransportAlgorithm::updatePathTable(uint32_t path_label) {
+  uint32_t path_id = path_label;
+
+  if (path_table_.find(path_id) == path_table_.end()) {
+    if (TRANSPORT_EXPECT_TRUE(cur_path_ != nullptr)) {
+      // Create a new path with some default param
+
+      if (TRANSPORT_EXPECT_FALSE(path_table_.empty())) {
+        throw errors::RuntimeException(
+            "[RAAQM] No path initialized for path table, error could be in "
+            "default path initialization.");
+      }
+
+      // Initiate the new path default param
+      auto new_path = std::make_unique<RaaqmDataPath>(
+          *(path_table_.at(interface::default_values::path_id)));
+
+      // Insert the new path into hash table
+      path_table_[path_id] = std::move(new_path);
+    } else {
+      throw errors::RuntimeException(
+          "UNEXPECTED ERROR: when running,current path not found.");
+    }
+  }
+
+  cur_path_ = path_table_[path_id].get();
+}
+
+void RaaqmTransportAlgorithm::checkDropProbability() {
+  if (!raaqm_autotune_) {
+    return;
+  }
+
+  unsigned int max_pd = 0;
+  PathTable::iterator it;
+  for (auto it = path_table_.begin(); it != path_table_.end(); ++it) {
+    if (it->second->getPropagationDelay() > max_pd &&
+        it->second->getPropagationDelay() != UINT_MAX &&
+        !it->second->isStale()) {
+      max_pd = it->second->getPropagationDelay();
+    }
+  }
+
+  double drop_prob = 0;
+  double beta = 0;
+  if (max_pd < wifi_delay_) {  // only ethernet paths
+    drop_prob = drop_factor_;
+    beta = beta_;
+  } else if (max_pd < lte_delay_) {  // at least one wifi path
+    drop_prob = drop_wifi_;
+    beta = beta_wifi_;
+  } else {  // at least one lte path
+    drop_prob = drop_lte_;
+    beta = beta_lte_;
+  }
+
+  double old_drop_prob = 0;
+  double old_beta = 0;
+  //   socket_->getSocketOption(RaaqmTransportOptions::BETA_VALUE, old_beta);
+  //   socket_->getSocketOption(RaaqmTransportOptions::DROP_FACTOR,
+  //   old_drop_prob);
+
+  if (drop_prob == old_drop_prob && beta == old_beta) {
+    return;
+  }
+
+  //   socket_->setSocketOption(RaaqmTransportOptions::BETA_VALUE, beta);
+  //   socket_->setSocketOption(RaaqmTransportOptions::DROP_FACTOR, drop_prob);
+
+  for (it = path_table_.begin(); it != path_table_.end(); it++) {
+    it->second->setDropProb(drop_prob);
+  }
+}
+
+void RaaqmTransportAlgorithm::checkForStalePaths() {
+  if (!raaqm_autotune_) {
+    return;
+  }
+
+  bool stale = false;
+  PathTable::iterator it;
+  for (it = path_table_.begin(); it != path_table_.end(); ++it) {
+    if (it->second->isStale()) {
+      stale = true;
+      break;
+    }
+  }
+  if (stale) {
+    checkDropProbability();
+  }
+}
+
+void RaaqmTransportAlgorithm::updateStats(uint32_t suffix, uint64_t rtt,
+                                          utils::TimePoint &now) {
+  // Update RTT statistics
+  if (stats_) {
+    stats_->updateAverageRtt(rtt);
+    stats_->updateAverageWindowSize(current_window_size_);
+  }
+}
+
+uint32_t RaaqmTransportAlgorithm::onContentObject(uint32_t suffix,
+                                                  uint32_t path_label) {
+  updatePathTable(path_label);
+  increaseWindow();
+  updateRtt(suffix);
+
+  // Set drop probablility and window size accordingly
+  RAAQM();
+
+  return current_window_size_;
+}
+
+uint32_t RaaqmTransportAlgorithm::onInterestTimeout(uint32_t suffix) {
+  checkForStalePaths();
+  // Decrease the window because the timeout happened
+  decreaseWindow();
+
+  return current_window_size_;
+}
+
+void RaaqmTransportAlgorithm::onInterestSent(uint32_t suffix) {
+  interest_timepoints_[suffix & mask] = utils::SteadyClock::now();
+}
+
+void RaaqmTransportAlgorithm::sessionEnd() {
+  rate_estimator_->onDownloadFinished();
+}
+
+}  // namespace protocol
+}  // namespace transport
\ No newline at end of file
diff --git a/libtransport/src/protocols/raaqm_transport_algorithm.h b/libtransport/src/protocols/raaqm_transport_algorithm.h
new file mode 100644
index 000000000..5b0b5c05c
--- /dev/null
+++ b/libtransport/src/protocols/raaqm_transport_algorithm.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2017-2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <hicn/transport/interfaces/socket_options_default_values.h>
+#include <hicn/transport/interfaces/statistics.h>
+#include <hicn/transport/utils/chrono_typedefs.h>
+#include <protocols/congestion_window_protocol.h>
+#include <protocols/raaqm_data_path.h>
+#include <protocols/rate_estimation.h>
+#include <protocols/transport_algorithm.h>
+
+#include <array>
+#include <queue>
+#include <unordered_map>
+#include <vector>
+
+namespace transport {
+
+namespace protocol {
+
+class RaaqmTransportAlgorithm : public TransportAlgorithm,
+                                public CWindowProtocol {
+ public:
+  // TODO: Add windows size and other beta/drop parameters
+  RaaqmTransportAlgorithm(interface::TransportStatistics *stats,
+                          IcnRateEstimator *rate_estimator, double drop_factor,
+                          double minimum_drop_probability, double gamma,
+                          double beta, uint32_t sample_number,
+                          uint32_t interest_lifetime, double beta_wifi,
+                          double drop_wifi, double beta_lte, double drop_lte,
+                          unsigned int wifi_delay, unsigned int lte_delay,
+                          double max_window, double min_window);
+
+  ~RaaqmTransportAlgorithm() override;
+
+  void reset() override;
+
+  uint32_t onContentObject(uint32_t suffix, uint32_t path_label) override;
+
+  uint32_t onInterestTimeout(uint32_t suffix) override;
+
+  void onInterestSent(uint32_t suffix) override;
+
+  void sessionEnd() override;
+
+ protected:
+  static constexpr uint32_t buffer_size =
+      1 << interface::default_values::log_2_default_buffer_size;
+  static constexpr uint16_t mask = buffer_size - 1;
+  using PathTable =
+      std::unordered_map<uint32_t, std::unique_ptr<RaaqmDataPath>>;
+
+  void increaseWindow() override;
+  void decreaseWindow() override;
+
+  virtual void updateStats(uint32_t suffix, uint64_t rtt,
+                           utils::TimePoint &now);
+
+ private:
+  void init();
+
+  void updateRtt(uint32_t suffix);
+
+  void RAAQM();
+
+  void updatePathTable(uint32_t path_label);
+
+  void checkDropProbability();
+
+  void checkForStalePaths();
+
+ protected:
+  // Congestion window management
+  double current_window_size_;
+  // Protocol management
+  uint64_t interests_in_flight_;
+  std::array<utils::TimePoint, buffer_size> interest_timepoints_;
+
+ private:
+  /**
+   * Current download path
+   */
+  RaaqmDataPath *cur_path_;
+
+  /**
+   * Hash table for path: each entry is a pair path ID(key) - path object
+   */
+  PathTable path_table_;
+
+  // for rate-estimation at packet level
+  IcnRateEstimator *rate_estimator_;
+  interface::TransportStatistics *stats_;
+
+  bool set_interest_filter_;
+
+  // Params
+  double drop_factor_;
+  double minimum_drop_probability_;
+  double gamma_;
+  double beta_;
+  uint32_t sample_number_;
+  uint32_t interest_lifetime_;
+
+  bool raaqm_autotune_;
+  double beta_wifi_;
+  double drop_wifi_;
+  double beta_lte_;
+  double drop_lte_;
+  unsigned int wifi_delay_;
+  unsigned int lte_delay_;
+  double max_window_;
+  double min_window_;
+};
+
+}  // end namespace protocol
+
+}  // end namespace transport
diff --git a/libtransport/src/protocols/transport_algorithm.cc b/libtransport/src/protocols/transport_algorithm.cc
new file mode 100644
index 000000000..2b8d60934
--- /dev/null
+++ b/libtransport/src/protocols/transport_algorithm.cc
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <hicn/transport/utils/log.h>
+#include <protocols/raaqm_transport_algorithm.h>
+#include <protocols/transport_algorithm.h>
+
+#include <stdexcept>
+
+namespace {
+allocator_t *algorithm_allocator = nullptr;
+deallocator_t *algorithm_deallocator = nullptr;
+
+void *custom_allocate(size_t size) {
+  void *ret;
+  if (algorithm_allocator) {
+    ret = algorithm_allocator(size);
+  } else {
+    ret = new uint8_t[size];
+  }
+
+  return ret;
+}
+
+void custom_deallocate(void *p) {
+  if (algorithm_deallocator) {
+    algorithm_deallocator(p);
+  } else {
+    delete[](char *)(p);
+  }
+}
+
+}  // namespace
+
+void transportAlgorithm_Init(allocator_t *allocator,
+                             deallocator_t *deallocator) {
+  algorithm_allocator = allocator;
+  algorithm_deallocator = deallocator;
+}
+
+void transportAlgorithm_Destroy(TransportAlgorithm *algorithm) {
+  custom_deallocate(algorithm);
+}
+
+TransportAlgorithm *transportAlgorithm_CreateRaaqm(
+    double drop_factor, double minimum_drop_probability, double gamma,
+    double beta, uint32_t sample_number, uint32_t interest_lifetime,
+    double beta_wifi, double drop_wifi, double beta_lte, double drop_lte,
+    unsigned int wifi_delay, unsigned int lte_delay, double max_window,
+    double min_window) {
+  TransportAlgorithm *ret = nullptr;
+  ret = new (
+      custom_allocate(sizeof(transport::protocol::RaaqmTransportAlgorithm)))
+      transport::protocol::RaaqmTransportAlgorithm(
+          nullptr, nullptr, drop_factor, minimum_drop_probability, gamma, beta,
+          sample_number, interest_lifetime, beta_wifi, drop_wifi, beta_lte,
+          drop_lte, wifi_delay, lte_delay, max_window, min_window);
+
+  return ret;
+}
+
+uint32_t transportAlgorithm_OnContentObject(TransportAlgorithm *algorithm,
+                                            uint32_t suffix,
+                                            uint32_t path_label) {
+  return algorithm->onContentObject(suffix, path_label);
+}
+
+uint32_t transportAlgorithm_OnInterestTimeout(TransportAlgorithm *algorithm,
+                                              uint32_t suffix) {
+  return algorithm->onInterestTimeout(suffix);
+}
\ No newline at end of file
diff --git a/libtransport/src/protocols/transport_algorithm.h b/libtransport/src/protocols/transport_algorithm.h
new file mode 100644
index 000000000..5dacdb3e0
--- /dev/null
+++ b/libtransport/src/protocols/transport_algorithm.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef transport_algorithm_h
+#define transport_algorithm_h
+
+#include <hicn/header.h>
+#include <hicn/transport/interfaces/socket_options_keys.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * TransportAlgorithm: class containing the protocol machinery
+ */
+#ifdef __cplusplus
+
+#include <hicn/transport/core/content_object.h>
+
+class TransportAlgorithm {
+ public:
+  virtual ~TransportAlgorithm() = default;
+  virtual void reset() = 0;
+  virtual uint32_t onContentObject(uint32_t suffix, uint32_t path_label) = 0;
+  virtual uint32_t onInterestTimeout(uint32_t suffix) = 0;
+  virtual void onInterestSent(uint32_t suffix) = 0;
+  virtual void sessionEnd() = 0;
+};
+
+using transport::interface::TransportProtocolAlgorithms;
+
+#else
+typedef void *TransportAlgorithm;
+#endif
+
+typedef void *(allocator_t)(size_t size);
+typedef void *(deallocator_t)(void *ptr);
+
+extern "C" void transportAlgorithm_Init(allocator_t *allocator,
+                                        deallocator_t *deallocator);
+
+extern "C" TransportAlgorithm *transportAlgorithm_CreateRaaqm(
+    double drop_factor, double minimum_drop_probability, double gamma,
+    double beta, uint32_t sample_number, uint32_t interest_lifetime,
+    double beta_wifi, double drop_wifi, double beta_lte, double drop_lte,
+    unsigned int wifi_delay, unsigned int lte_delay, double max_window,
+    double min_window);
+
+extern "C" void transportAlgorithm_Destroy(TransportAlgorithm *algorithm);
+
+extern "C" uint32_t transportAlgorithm_OnContentObject(
+    TransportAlgorithm *algorithm, uint32_t suffix, uint32_t path_label);
+
+extern "C" uint32_t transportAlgorithm_OnInterestTimeout(
+    TransportAlgorithm *algorithm, uint32_t suffix);
+
+#endif /* transport_algorithm_h */
\ No newline at end of file