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/*
* 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
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