1 files changed, 85 insertions, 0 deletions
diff --git a/libtransport/src/hicn/transport/protocols/rtc_data_path.cc b/libtransport/src/hicn/transport/protocols/rtc_data_path.cc
new file mode 100755
index 000000000..6c9605fb2
--- /dev/null
+++ b/libtransport/src/hicn/transport/protocols/rtc_data_path.cc
@@ -0,0 +1,85 @@
+/*
+ * 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.
+ */
+
+#include <hicn/transport/protocols/rtc_data_path.h>
+
+namespace transport {
+
+namespace protocol {
+
+RTCDataPath::RTCDataPath()
+    : min_rtt(UINT_MAX),
+      prev_min_rtt(UINT_MAX),
+      min_owd(INT_MAX),  // this is computed like in LEDBAT, so it is not the
+                         // real OWD, but the measured one, that depends on the
+                         // clock of sender and receiver. the only meaningful
+                         // value is is the queueing delay. for this reason we
+                         // keep both RTT (for the windowd calculation) and OWD
+                         // (for congestion/quality control)
+      prev_min_owd(INT_MAX),
+      avg_owd(0.0),
+      queuing_delay(0.0),
+      RTThistory_(HISTORY_LEN),
+      OWDhistory_(HISTORY_LEN){};
+
+void RTCDataPath::insertRttSample(uint64_t rtt) {
+  // for the rtt we only keep track of the min one
+  if (rtt < min_rtt) min_rtt = rtt;
+}
+
+void RTCDataPath::insertOwdSample(int64_t owd) {
+  // for owd we use both min and avg
+  if (owd < min_owd) min_owd = owd;
+
+  avg_owd = (avg_owd * (1 - ALPHA_RTC)) + (owd * ALPHA_RTC);
+}
+
+void RTCDataPath::roundEnd() {
+  // compute queuing delay
+  queuing_delay = avg_owd - getMinOwd();
+
+  // reset min_rtt and add it to the history
+  if (min_rtt != UINT_MAX) {
+    prev_min_rtt = min_rtt;
+  } else {
+    // this may happen if we do not receive any packet
+    // from this path in the last round. in this case
+    // we use the measure from the previuos round
+    min_rtt = prev_min_rtt;
+  }
+
+  RTThistory_.pushBack(min_rtt);
+  min_rtt = UINT_MAX;
+
+  // do the same for min owd
+  if (min_owd != INT_MAX) {
+    prev_min_owd = min_owd;
+  } else {
+    min_owd = prev_min_owd;
+  }
+
+  OWDhistory_.pushBack(min_owd);
+  min_owd = INT_MAX;
+}
+
+double RTCDataPath::getQueuingDealy() { return queuing_delay; }
+
+uint64_t RTCDataPath::getMinRtt() { return RTThistory_.begin(); }
+
+int64_t RTCDataPath::getMinOwd() { return OWDhistory_.begin(); }
+
+}  // end namespace protocol
+
+}  // end namespace transport