draft-ietf-quic-recovery-00.txt   draft-ietf-quic-recovery-01.txt 
QUIC J. Iyengar, Ed. QUIC J. Iyengar, Ed.
Internet-Draft I. Swett, Ed. Internet-Draft I. Swett, Ed.
Intended status: Standards Track Google Intended status: Standards Track Google
Expires: June 1, 2017 November 28, 2016 Expires: July 18, 2017 January 14, 2017
QUIC Loss Detection and Congestion Control QUIC Loss Detection and Congestion Control
draft-ietf-quic-recovery-00 draft-ietf-quic-recovery-01
Abstract Abstract
QUIC is a new multiplexed and secure transport atop UDP. QUIC builds QUIC is a new multiplexed and secure transport atop UDP. QUIC builds
on decades of transport and security experience, and implements on decades of transport and security experience, and implements
mechanisms that make it attractive as a modern general-purpose mechanisms that make it attractive as a modern general-purpose
transport. QUIC implements the spirit of known TCP loss detection transport. QUIC implements the spirit of known TCP loss detection
mechanisms, described in RFCs, various Internet-drafts, and also mechanisms, described in RFCs, various Internet-drafts, and also
those prevalent in the Linux TCP implementation. This document those prevalent in the Linux TCP implementation. This document
describes QUIC loss detection and congestion control, and attributes describes QUIC loss detection and congestion control, and attributes
the TCP equivalent in RFCs, Internet-drafts, academic papers, and TCP the TCP equivalent in RFCs, Internet-drafts, academic papers, and TCP
implementations. implementations.
Note to Readers
Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/search/?email_list=quic .
Working Group information can be found at https://github.com/quicwg ;
source code and issues list for this draft can be found at
https://github.com/quicwg/base-drafts/labels/recovery .
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 1, 2017. This Internet-Draft will expire on July 18, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
2. Design of the QUIC Transmission Machinery . . . . . . . . . . 3 2. Design of the QUIC Transmission Machinery . . . . . . . . . . 3
2.1. Relevant Differences Between QUIC and TCP . . . . . . . . 4 2.1. Relevant Differences Between QUIC and TCP . . . . . . . . 4
2.1.1. Monotonically Increasing Packet Numbers . . . . . . . 4 2.1.1. Monotonically Increasing Packet Numbers . . . . . . . 4
2.1.2. No Reneging . . . . . . . . . . . . . . . . . . . . . 4 2.1.2. No Reneging . . . . . . . . . . . . . . . . . . . . . 5
2.1.3. More ACK Ranges . . . . . . . . . . . . . . . . . . . 4 2.1.3. More ACK Ranges . . . . . . . . . . . . . . . . . . . 5
2.1.4. Explicit Correction For Delayed Acks . . . . . . . . 5 2.1.4. Explicit Correction For Delayed Acks . . . . . . . . 5
3. Loss Detection . . . . . . . . . . . . . . . . . . . . . . . 5 3. Loss Detection . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Variables of interest . . . . . . . . . . . . . . . . . . 5 3.1. Constants of interest . . . . . . . . . . . . . . . . . . 5
3.2. Initialization . . . . . . . . . . . . . . . . . . . . . 6 3.2. Variables of interest . . . . . . . . . . . . . . . . . . 6
3.3. Setting the Loss Detection Alarm . . . . . . . . . . . . 6 3.3. Initialization . . . . . . . . . . . . . . . . . . . . . 6
3.4. On Sending a Packet . . . . . . . . . . . . . . . . . . . 7 3.4. Setting the Loss Detection Alarm . . . . . . . . . . . . 7
3.5. On Packet Acknowledgment . . . . . . . . . . . . . . . . 7 3.5. On Sending a Packet . . . . . . . . . . . . . . . . . . . 8
3.6. On Alarm Firing . . . . . . . . . . . . . . . . . . . . . 7 3.6. On Ack Receipt . . . . . . . . . . . . . . . . . . . . . 8
3.7. Detecting Lost Packets . . . . . . . . . . . . . . . . . 8 3.7. On Packet Acknowledgment . . . . . . . . . . . . . . . . 9
4. Congestion Control . . . . . . . . . . . . . . . . . . . . . 8 3.8. On Alarm Firing . . . . . . . . . . . . . . . . . . . . . 10
5. TCP mechanisms in QUIC . . . . . . . . . . . . . . . . . . . 8 3.9. Detecting Lost Packets . . . . . . . . . . . . . . . . . 10
5.1. RFC 6298 (RTO computation) . . . . . . . . . . . . . . . 8 4. Congestion Control . . . . . . . . . . . . . . . . . . . . . 10
5.2. FACK Loss Recovery (paper) . . . . . . . . . . . . . . . 9 5. TCP mechanisms in QUIC . . . . . . . . . . . . . . . . . . . 10
5.3. RFC 3782, RFC 6582 (NewReno Fast Recovery) . . . . . . . 9 5.1. RFC 6298 (RTO computation) . . . . . . . . . . . . . . . 11
5.4. TLP (draft) . . . . . . . . . . . . . . . . . . . . . . . 9 5.2. FACK Loss Recovery (paper) . . . . . . . . . . . . . . . 11
5.5. RFC 5827 (Early Retransmit) with Delay Timer . . . . . . 9 5.3. RFC 3782, RFC 6582 (NewReno Fast Recovery) . . . . . . . 11
5.6. RFC 5827 (F-RTO) . . . . . . . . . . . . . . . . . . . . 9 5.4. TLP (draft) . . . . . . . . . . . . . . . . . . . . . . . 11
5.7. RFC 6937 (Proportional Rate Reduction) . . . . . . . . . 10 5.5. RFC 5827 (Early Retransmit) with Delay Timer . . . . . . 11
5.8. TCP Cubic (draft) with optional RFC 5681 (Reno) . . . . . 10 5.6. RFC 5827 (F-RTO) . . . . . . . . . . . . . . . . . . . . 12
5.9. Hybrid Slow Start (paper) . . . . . . . . . . . . . . . . 10 5.7. RFC 6937 (Proportional Rate Reduction) . . . . . . . . . 12
5.10. RACK (draft) . . . . . . . . . . . . . . . . . . . . . . 10 5.8. TCP Cubic (draft) with optional RFC 5681 (Reno) . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5.9. Hybrid Slow Start (paper) . . . . . . . . . . . . . . . . 12
7. Normative References . . . . . . . . . . . . . . . . . . . . 10 5.10. RACK (draft) . . . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 11 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 7. Normative References . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 13
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 13
B.1. Since draft-ietf-quic-recovery-00: . . . . . . . . . . . 13
B.2. Since draft-iyengar-quic-loss-recovery-01: . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
QUIC is a new multiplexed and secure transport atop UDP. QUIC builds QUIC is a new multiplexed and secure transport atop UDP. QUIC builds
on decades of transport and security experience, and implements on decades of transport and security experience, and implements
mechanisms that make it attractive as a modern general-purpose mechanisms that make it attractive as a modern general-purpose
transport. The QUIC protocol is described in [QUIC-TRANSPORT]. transport. The QUIC protocol is described in [QUIC-TRANSPORT].
QUIC implements the spirit of known TCP loss recovery mechanisms, QUIC implements the spirit of known TCP loss recovery mechanisms,
described in RFCs, various Internet-drafts, and also those prevalent described in RFCs, various Internet-drafts, and also those prevalent
skipping to change at page 5, line 22 skipping to change at page 5, line 34
delay from when a packet was received by the OS kernel, which is delay from when a packet was received by the OS kernel, which is
useful in receivers which may incur delays such as context-switch useful in receivers which may incur delays such as context-switch
latency before a userspace QUIC receiver processes a received packet. latency before a userspace QUIC receiver processes a received packet.
3. Loss Detection 3. Loss Detection
We now describe QUIC's loss detection as functions that should be We now describe QUIC's loss detection as functions that should be
called on packet transmission, when a packet is acked, and timer called on packet transmission, when a packet is acked, and timer
expiration events. expiration events.
3.1. Variables of interest 3.1. Constants of interest
Constants used in loss recovery and congestion control are based on a
combination of RFCs, papers, and common practice. Some may need to
be changed or negotiated in order to better suit a variety of
environments.
o kMaxTLPs: 2 Maximum number of tail loss probes before an RTO
fires.
o kReorderingThreshold: 3 Maximum reordering in packet number space
before FACK style loss detection considers a packet lost.
o kTimeReorderingThreshold: 1/8 Maximum reordering in time sapce
before time based loss detection considers a packet lost. In
fraction of an RTT.
o kMinTLPTimeout: 10ms Minimum time in the future a tail loss probe
alarm may be set for.
o kMinRTOTimeout: 200ms Minimum time in the future an RTO alarm may
be set for.
o kDelayedAckTimeout: 25ms The length of the peer's delayed ack
timer.
3.2. Variables of interest
We first describe the variables required to implement the loss We first describe the variables required to implement the loss
detection mechanisms described in this section. detection mechanisms described in this section.
o loss_detection_alarm: Multi-modal alarm used for loss detection. o loss_detection_alarm: Multi-modal alarm used for loss detection.
o alarm_mode: QUIC maintains a single loss detection alarm, which o alarm_mode: QUIC maintains a single loss detection alarm, which
switches between various modes. This mode is used to determine switches between various modes. This mode is used to determine
the duration of the alarm. the duration of the alarm.
o handshake_count: The number of times the handshake packets have o handshake_count: The number of times the handshake packets have
been retransmitted without receiving an ack. been retransmitted without receiving an ack.
o tlp_count: The number of times a tail loss probe has been sent o tlp_count: The number of times a tail loss probe has been sent
without receiving an ack. without receiving an ack.
o rto_count: The number of times an rto has been sent without o rto_count: The number of times an rto has been sent without
receiving an ack. receiving an ack.
o smoothed_rtt: The smoothed RTT of the connection, computed as o smoothed_rtt: The smoothed RTT of the connection, computed as
described in [RFC6298]. TODO: Describe RTT computations. described in [RFC6298]
o rttvar: The RTT variance.
o reordering_threshold: The largest delta between the largest acked o reordering_threshold: The largest delta between the largest acked
retransmittable packet and a packet containing retransmittable retransmittable packet and a packet containing retransmittable
frames before it's declared lost. frames before it's declared lost.
o time_loss: When true, loss detection operates solely based on o use_time_loss: When true, loss detection operates solely based on
reordering threshold in time, rather than in packet number gaps. reordering threshold in time, rather than in packet number gaps.
3.2. Initialization o sent_packets: An association of packet numbers to information
about them.
3.3. Initialization
At the beginning of the connection, initialize the loss detection At the beginning of the connection, initialize the loss detection
variables as follows: variables as follows:
loss_detection_alarm.reset(); loss_detection_alarm.reset();
handshake_count = 0; handshake_count = 0;
tlp_count = 0; tlp_count = 0;
rto_count = 0; rto_count = 0;
reordering_threshold = kReorderingThreshold;
use_time_loss = false;
smoothed_rtt = 0; smoothed_rtt = 0;
reordering_threshold = 3; rttvar = 0;
time_loss = false;
3.3. Setting the Loss Detection Alarm 3.4. Setting the Loss Detection Alarm
QUIC loss detection uses a single alarm for all timer-based loss QUIC loss detection uses a single alarm for all timer-based loss
detection. The duration of the alarm is based on the alarm's mode, detection. The duration of the alarm is based on the alarm's mode,
which is set in the packet and timer events further below. The which is set in the packet and timer events further below. The
function SetLossDetectionAlarm defined below shows how the single function SetLossDetectionAlarm defined below shows how the single
timer is set based on the alarm mode. timer is set based on the alarm mode.
Pseudocode for SetLossDetectionAlarm follows: Pseudocode for SetLossDetectionAlarm follows:
SetLossDetectionAlarm(): SetLossDetectionAlarm():
skipping to change at page 6, line 32 skipping to change at page 7, line 28
which is set in the packet and timer events further below. The which is set in the packet and timer events further below. The
function SetLossDetectionAlarm defined below shows how the single function SetLossDetectionAlarm defined below shows how the single
timer is set based on the alarm mode. timer is set based on the alarm mode.
Pseudocode for SetLossDetectionAlarm follows: Pseudocode for SetLossDetectionAlarm follows:
SetLossDetectionAlarm(): SetLossDetectionAlarm():
if (retransmittable packets are not outstanding): if (retransmittable packets are not outstanding):
loss_detection_alarm.cancel(); loss_detection_alarm.cancel();
return; return;
if (handshake packets are outstanding): if (handshake packets are outstanding):
alarm_duration = max(1.5 * smoothed_rtt, 10ms) << handshake_count; // Handshake retransmission alarm.
alarm_duration = max(1.5 * smoothed_rtt, kMinTLPTimeout) << handshake_count;
handshake_count++; handshake_count++;
else if (largest sent packet is acked): else if (largest sent packet is acked):
// Set alarm based on short timer for early retransmit. // Early retransmit alarm.
alarm_duration = 0.25 x smoothed_rtt; alarm_duration = 0.25 x smoothed_rtt;
else if (tlp_count < 2): else if (tlp_count < kMaxTLPs):
// Tail Loss Probe alarm.
if (retransmittable_packets_outstanding = 1): if (retransmittable_packets_outstanding = 1):
alarm_duration = max(1.5 x smoothed_rtt + delayed_ack_timer, alarm_duration = max(1.5 x smoothed_rtt + kDelayedAckTimeout,
2 x smoothed_rtt); 2 x smoothed_rtt);
else: else:
alarm_duration = max (10ms, 2 x smoothed_rtt); alarm_duration = max (kMinTLPTimeout, 2 x smoothed_rtt);
tlp_count++; tlp_count++;
else: else:
// RTO alarm.
if (rto_count = 0): if (rto_count = 0):
alarm_duration = max(200ms, smoothed_rtt + 4 x rttvar); alarm_duration = max(kMinRTOTimeout, smoothed_rtt + 4 x rttvar);
else: else:
alarm_duration = loss_detection_alarm.get_delay() << 1; alarm_duration = loss_detection_alarm.get_delay() << 1;
rto_count++; rto_count++;
loss_detection_alarm.set(now + alarm_duration); loss_detection_alarm.set(now + alarm_duration);
3.4. On Sending a Packet 3.5. On Sending a Packet
After any packet is sent, be it a new transmission or a rebundled After any packet is sent, be it a new transmission or a rebundled
transmission, the following OnPacketSent function is called. The transmission, the following OnPacketSent function is called. The
parameters to OnPacketSent are as follows: parameters to OnPacketSent are as follows:
o packet_number: The packet number of the sent packet. o packet_number: The packet number of the sent packet.
o is_retransmittble: A boolean that indicates whether the packet o is_retransmittble: A boolean that indicates whether the packet
contains at least one frame requiring reliable deliver. The contains at least one frame requiring reliable deliver. The
retransmittability of various QUIC frames is described in retransmittability of various QUIC frames is described in
[QUIC-TRANSPORT]. If false, it is still acceptable for an ack to [QUIC-TRANSPORT]. If false, it is still acceptable for an ack to
be received for this packet. However, a caller MUST NOT set be received for this packet. However, a caller MUST NOT set
is_retransmittable to true if an ack is not expected. is_retransmittable to true if an ack is not expected.
Pseudocode for OnPacketSent follows: Pseudocode for OnPacketSent follows:
OnPacketSent(packet_number, is_retransmittable): OnPacketSent(packet_number, is_retransmittable):
if is_retransmittable: # TODO: Clarify the data in sent_packets.
SetLossDetectionAlarm() sent_packets[packet_number] = {now}
if is_retransmittable:
SetLossDetectionAlarm()
3.5. On Packet Acknowledgment 3.6. On Ack Receipt
When an ack is received, it may acknowledge 0 or more packets.
Pseudocode for OnAckReceived and UpdateRtt follow:
OnAckReceived(ack):
// If the largest acked is newly acked, update the RTT.
if (sent_packets[ack.largest_acked]):
rtt_sample = now - sent_packets[ack.largest_acked]
if (rtt_sample > ack.ack_delay):
rtt_sample -= ack.delay;
UpdateRtt(rtt_sample)
// Find all newly acked packets.
for acked_packet in DetermineNewlyAckedPackets():
OnPacketAcked(acked_packet)
DetectLostPackets(ack.largest_acked_packet);
SetLossDetectionAlarm();
UpdateRtt(rtt_sample):
if (smoothed_rtt == 0):
smoothed_rtt = rtt_sample
rttvar = rtt_sample / 2
else:
rttvar = 3/4 * rttvar + 1/4 * (smoothed_rtt - rtt_sample)
smoothed_rtt = 7/8 * smoothed_rtt + 1/8 * rtt_sample
3.7. On Packet Acknowledgment
When a packet is acked for the first time, the following When a packet is acked for the first time, the following
OnPacketAcked function is called. Note that a single ACK frame may OnPacketAcked function is called. Note that a single ACK frame may
newly acknowledge several packets. OnPacketAcked must be called once newly acknowledge several packets. OnPacketAcked must be called once
for each of these newly acked packets. for each of these newly acked packets.
OnPacketAcked takes one parameter, acked_packet, which is the packet OnPacketAcked takes one parameter, acked_packet, which is the packet
number of the newly acked packet, and returns a list of packet number of the newly acked packet, and returns a list of packet
numbers that are detected as lost. numbers that are detected as lost.
Pseudocode for OnPacketAcked follows: Pseudocode for OnPacketAcked follows:
OnPacketAcked(acked_packet): OnPacketAcked(acked_packet):
handshake_count = 0; handshake_count = 0;
tlp_count = 0; tlp_count = 0;
rto_count = 0; rto_count = 0;
UpdateRtt(); // TODO: document RTT estimator. # TODO: Don't remove packets immediately, since they can be used for
DetectLostPackets(acked_packet); # detecting spurous retransmits.
SetLossDetectionAlarm(); sent_packets.remove(acked_packet);
3.6. On Alarm Firing 3.8. On Alarm Firing
QUIC uses one loss recovery alarm, which when set, can be in one of QUIC uses one loss recovery alarm, which when set, can be in one of
several modes. When the alarm fires, the mode determines the action several modes. When the alarm fires, the mode determines the action
to be performed. OnAlarm returns a list of packet numbers that are to be performed. OnAlarm returns a list of packet numbers that are
detected as lost. detected as lost.
Pseudocode for OnAlarm follows: Pseudocode for OnAlarm follows:
OnAlarm(acked_packet): OnAlarm(acked_packet):
lost_packets = DetectLostPackets(acked_packet); lost_packets = DetectLostPackets(acked_packet);
MaybeRetransmitLostPackets(); MaybeRetransmitLostPackets();
SetLossDetectionAlarm(); SetLossDetectionAlarm();
3.7. Detecting Lost Packets 3.9. Detecting Lost Packets
Packets in QUIC are only considered lost once a larger packet number Packets in QUIC are only considered lost once a larger packet number
is acknowledged. DetectLostPackets is called every time there is a is acknowledged. DetectLostPackets is called every time there is a
new largest packet or if the loss detection alarm fires the previous new largest packet or if the loss detection alarm fires the previous
largest acked packet is supplied. largest acked packet is supplied.
DetectLostPackets takes one parameter, acked_packet, which is the DetectLostPackets takes one parameter, acked_packet, which is the
packet number of the largest acked packet, and returns a list of packet number of the largest acked packet, and returns a list of
packet numbers detected as lost. packet numbers detected as lost.
Pseudocode for DetectLostPackets follows: Pseudocode for DetectLostPackets follows:
DetectLostPackets(acked_packet): DetectLostPackets(acked_packet):
lost_packets = {}; lost_packets = {};
foreach (unacked_packet less than acked_packet): foreach (unacked_packet less than acked_packet):
if (unacked_packet.time_sent < if (unacked_packet.time_sent <
acked_packet.time_sent - 1/8 * smoothed_rtt): acked_packet.time_sent - kTimeReorderThreshold * smoothed_rtt):
lost_packets.insert(unacked_packet.packet_number); lost_packets.insert(unacked_packet.packet_number);
else if (unacked_packet.packet_number < else if (unacked_packet.packet_number <
acked_packet.packet_number - reordering_threshold) acked_packet.packet_number - reordering_threshold)
lost_packets.insert(unacked_packet.packet_number); lost_packets.insert(unacked_packet.packet_number);
return lost_packets; return lost_packets;
4. Congestion Control 4. Congestion Control
(describe NewReno-style congestion control for QUIC.) (describe NewReno-style congestion control for QUIC.)
5. TCP mechanisms in QUIC 5. TCP mechanisms in QUIC
QUIC implements the spirit of a variety of RFCs, Internet drafts, and QUIC implements the spirit of a variety of RFCs, Internet drafts, and
other well-known TCP loss recovery mechanisms, though the other well-known TCP loss recovery mechanisms, though the
implementation details differ from the TCP implementations. implementation details differ from the TCP implementations.
skipping to change at page 10, line 40 skipping to change at page 12, line 47
of an rtt, as RACK does. of an rtt, as RACK does.
6. IANA Considerations 6. IANA Considerations
This document has no IANA actions. Yet. This document has no IANA actions. Yet.
7. Normative References 7. Normative References
[QUIC-TLS] [QUIC-TLS]
Thomson, M., Ed. and S. Turner, Ed, Ed., "Using Transport Thomson, M., Ed. and S. Turner, Ed, Ed., "Using Transport
Layer Security (TLS) to Secure QUIC", November 2016. Layer Security (TLS) to Secure QUIC".
[QUIC-TRANSPORT] [QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", November 2016. Multiplexed and Secure Transport".
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC6298] Paxson, V., Allman, M., Chu, J., and M. Sargent, [RFC6298] Paxson, V., Allman, M., Chu, J., and M. Sargent,
"Computing TCP's Retransmission Timer", RFC 6298, "Computing TCP's Retransmission Timer", RFC 6298,
DOI 10.17487/RFC6298, June 2011, DOI 10.17487/RFC6298, June 2011,
<http://www.rfc-editor.org/info/rfc6298>. <http://www.rfc-editor.org/info/rfc6298>.
Appendix A. Acknowledgments Appendix A. Acknowledgments
Appendix B. Change Log
*RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document.
B.1. Since draft-ietf-quic-recovery-00:
o Improved description of constants and ACK behavior
B.2. Since draft-iyengar-quic-loss-recovery-01:
o Adopted as base for draft-ietf-quic-recovery.
o Updated authors/editors list.
o Added table of contents.
Authors' Addresses Authors' Addresses
Jana Iyengar (editor) Jana Iyengar (editor)
Google Google
Email: jri@google.com Email: jri@google.com
Ian Swett (editor) Ian Swett (editor)
Google Google
 End of changes. 33 change blocks. 
68 lines changed or deleted 166 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/