1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef NET_QUIC_CONGESTION_CONTROL_TIME_LOSS_ALGORITHM_H_
6 #define NET_QUIC_CONGESTION_CONTROL_TIME_LOSS_ALGORITHM_H_
11 #include "base/basictypes.h"
12 #include "net/quic/congestion_control/loss_detection_interface.h"
13 #include "net/quic/quic_protocol.h"
14 #include "net/quic/quic_time.h"
15 #include "net/quic/quic_unacked_packet_map.h"
19 // A loss detection algorithm which avoids spurious losses and retransmissions
20 // by waiting 1.25 RTTs after a packet was sent instead of nack count.
21 class NET_EXPORT_PRIVATE TimeLossAlgorithm : public LossDetectionInterface {
24 ~TimeLossAlgorithm() override {}
26 LossDetectionType GetLossDetectionType() const override;
28 // Declares pending packets less than the largest observed lost when it has
29 // been 1.25 RTT since they were sent. Packets larger than the largest
30 // observed are retransmitted via TLP.
31 SequenceNumberSet DetectLostPackets(
32 const QuicUnackedPacketMap& unacked_packets,
34 QuicPacketSequenceNumber largest_observed,
35 const RttStats& rtt_stats) override;
37 // Returns the time the next packet will be lost, or zero if there
38 // are no nacked pending packets outstanding.
39 // TODO(ianswett): Ideally the RTT variance and the RTT would be used to
40 // determine the time a packet is considered lost.
41 // TODO(ianswett): Consider using Max(1.25 * srtt, 1.125 * last_rtt).
42 QuicTime GetLossTimeout() const override;
45 QuicTime loss_detection_timeout_;
47 DISALLOW_COPY_AND_ASSIGN(TimeLossAlgorithm);
52 #endif // NET_QUIC_CONGESTION_CONTROL_TIME_LOSS_ALGORITHM_H_