Internet DRAFT - draft-ietf-tcpm-alternativebackoff-ecn
draft-ietf-tcpm-alternativebackoff-ecn
Network Working Group N. Khademi
Internet-Draft M. Welzl
Intended status: Experimental University of Oslo
Expires: March 18, 2019 G. Armitage
Netflix
G. Fairhurst
University of Aberdeen
September 14, 2018
TCP Alternative Backoff with ECN (ABE)
draft-ietf-tcpm-alternativebackoff-ecn-12
Abstract
Active Queue Management (AQM) mechanisms allow for burst tolerance
while enforcing short queues to minimise the time that packets spend
enqueued at a bottleneck. This can cause noticeable performance
degradation for TCP connections traversing such a bottleneck,
especially if there are only a few flows or their bandwidth-delay-
product is large. The reception of a Congestion Experienced (CE) ECN
mark indicates that an AQM mechanism is used at the bottleneck, and
therefore the bottleneck network queue is likely to be short.
Feedback of this signal allows the TCP sender-side ECN reaction in
congestion avoidance to reduce the Congestion Window (cwnd) by a
smaller amount than the congestion control algorithm's reaction to
inferred packet loss. This specification therefore defines an
experimental change to the TCP reaction specified in RFC3168, as
permitted by RFC 8311.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 18, 2019.
Khademi, et al. Expires March 18, 2019 [Page 1]
Internet-Draft ABE September 2018
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Specification . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Choice of ABE Multiplier . . . . . . . . . . . . . . . . 4
4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Why Use ECN to Vary the Degree of Backoff? . . . . . . . 6
4.2. An RTT-based response to indicated congestion . . . . . . 7
5. ABE Deployment Requirements . . . . . . . . . . . . . . . . . 7
6. ABE Experiment Goals . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Implementation Status . . . . . . . . . . . . . . . . . . . . 9
10. Security Considerations . . . . . . . . . . . . . . . . . . . 9
11. Revision Information . . . . . . . . . . . . . . . . . . . . 9
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
12.1. Normative References . . . . . . . . . . . . . . . . . . 11
12.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
Explicit Congestion Notification (ECN) [RFC3168] makes it possible
for an Active Queue Management (AQM) mechanism to signal the presence
of incipient congestion without necessarily incurring packet loss.
This lets the network deliver some packets to an application that
would have been dropped if the application or transport did not
support ECN. This packet loss reduction is the most obvious benefit
of ECN, but it is often relatively modest. Other benefits of
deploying ECN have been documented in RFC8087 [RFC8087].
Khademi, et al. Expires March 18, 2019 [Page 2]
Internet-Draft ABE September 2018
The rules for ECN were originally written to be very conservative,
and required the congestion control algorithms of ECN-Capable
transport protocols to treat indications of congestion signalled by
ECN exactly the same as they would treat an inferred packet loss
[RFC3168]. Research has demonstrated the benefits of reducing
network delays that are caused by interaction of loss-based TCP
congestion control and excessive buffering [BUFFERBLOAT]. This has
led to the creation of AQM mechanisms like Proportional Integral
Controller Enhanced (PIE) [RFC8033] and Controlling Queue Delay
(CoDel) [CODEL2012][RFC8289], which prevent bloated queues that are
common with unmanaged and excessively large buffers deployed across
the Internet [BUFFERBLOAT].
The AQM mechanisms mentioned above aim to keep a sustained queue
short while tolerating transient (short-term) packet bursts.
However, currently used loss-based congestion control mechanisms are
not always able to effectively utilise a bottleneck link where there
are short queues. For example, a TCP sender using the Reno
congestion control needs to be able to store at least an end-to-end
bandwidth-delay product (BDP) worth of data at the bottleneck buffer
if it is to maintain full path utilisation in the face of loss-
induced reduction of the congestion window (cwnd) [RFC5681]. This
amount of buffering effectively doubles the amount of data that can
be in flight and the maximum round-trip time (RTT) experienced by the
TCP sender.
Modern AQM mechanisms can use ECN to signal the early signs of
impending queue buildup long before a tail-drop queue would be forced
to resort to dropping packets. It is therefore appropriate for the
transport protocol congestion control algorithm to have a more
measured response when it receives an indication with an early-
warning of congestion after the remote endpoint receives an ECN CE-
marked packet. Recognizing these changes in modern AQM practices,
the strict requirement that ECN CE signals be treated identically to
inferred packet loss has been relaxed [RFC8311]. This document
therefore defines a new sender-side-only congestion control response,
called "ABE" (Alternative Backoff with ECN). ABE improves TCP's
average throughput when routers use AQM controlled buffers that allow
only for short queues.
2. Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 RFC 2119 [RFC2119] [RFC8174] when, and only when, they appear in
all capitals, as shown here.
Khademi, et al. Expires March 18, 2019 [Page 3]
Internet-Draft ABE September 2018
3. Specification
This specification changes the congestion control algorithm of an
ECN-Capable TCP transport protocol by changing the TCP sender
response to feedback from the TCP receiver that indicates reception
of a CE-marked packet, i.e., receipt of a packet with the ECN-Echo
flag (defined in [RFC3168]) set, following the process defined in
[RFC8311].
The TCP sender response is currently specified in section 6.1.2 of
the ECN specification [RFC3168], updated by [RFC8311]:
The indication of congestion should be treated just as a
congestion loss in non-ECN-Capable TCP. That is, the TCP source
halves the congestion window "cwnd" and reduces the slow start
threshold "ssthresh", unless otherwise specified by an
Experimental RFC in the IETF document stream.
Following publication of RFC 8311, this document specifies a sender-
side change to TCP:
Receipt of a packet with the ECN-Echo flag SHOULD trigger the TCP
source to set the slow start threshold (ssthresh) to 0.8 times the
FlightSize, with a lower bound of 2 * SMSS applied to the result.
As in [RFC5681], the TCP sender also reduces the cwnd value to no
more than the new ssthresh value. RFC 3168 section 6.1.2 provides
guidance on setting a cwnd less than 2 * SMSS.
3.1. Choice of ABE Multiplier
ABE decouples the reaction of a TCP sender to inferred packet loss
and indication of ECN-signalled congestion in the congestion
avoidance phase. To achieve this, ABE uses a different scaling
factor in Equation 4 in Section 3.1 of [RFC5681]. The description
respectively uses beta_{loss} and beta_{ecn} to refer to the
multiplicative decrease factors applied in response to inferred
packet loss, and in response to a receiver indicating ECN-signalled
congestion. For non-ECN-enabled TCP connections, only beta_{loss}
applies.
In other words, in response to inferred packet loss:
ssthresh = max (FlightSize * beta_{loss}, 2 * SMSS)
and in response to an indication of an ECN-signalled congestion:
ssthresh = max (FlightSize * beta_{ecn}, 2 * SMSS)
Khademi, et al. Expires March 18, 2019 [Page 4]
Internet-Draft ABE September 2018
and
cwnd = ssthresh
(If ssthresh == 2 * SMSS, RFC 3168 section 6.1.2 provides guidance
on setting a cwnd lower than 2 * SMSS.)
where FlightSize is the amount of outstanding data in the network,
upper-bounded by the smaller of the sender's cwnd and the receiver's
advertised window (rwnd) [RFC5681]. The higher the values of
beta_{loss} and beta_{ecn}, the less aggressive the response of any
individual backoff event.
The appropriate choice for beta_{loss} and beta_{ecn} values is a
balancing act between path utilisation and draining the bottleneck
queue. More aggressive backoff (smaller beta_*) risks underutilising
the path, while less aggressive backoff (larger beta_*) can result in
slower draining of the bottleneck queue.
The Internet has already been running with at least two different
beta_{loss} values for several years: the standard value is 0.5
[RFC5681], and the Linux implementation of CUBIC [RFC8312] has used a
multiplier of 0.7 since kernel version 2.6.25 released in 2008. ABE
does not change the value of beta_{loss} used by current TCP
implementations.
The recommendation in this document specifies a value of
beta_{ecn}=0.8. This recommended beta_{ecn} value is only applicable
for the standard TCP congestion control [RFC5681]. The selection of
beta_{ecn} enables tuning the response of a TCP connection to shallow
AQM marking thresholds. beta_{loss} characterizes the response of a
congestion control algorithm to packet loss, i.e., exhaustion of
buffers (of unknown depth). Different values for beta_{loss} have
been suggested for TCP congestion control algorithms. Consequently,
beta_{ecn} is likely to be an algorithm-specific parameter rather
than a constant multiple of the algorithm's existing beta_{loss}.
A range of tests (section IV, [ABE2017]) with NewReno and CUBIC over
CoDel and PIE in lightly-multiplexed scenarios have explored this
choice of parameter. The results of these tests indicate that CUBIC
connections benefit from beta_{ecn} of 0.85 (cf. beta_{loss} = 0.7),
and NewReno connections see improvements with beta_{ecn} in the range
0.7 to 0.85 (cf. beta_{loss} = 0.5).
Khademi, et al. Expires March 18, 2019 [Page 5]
Internet-Draft ABE September 2018
4. Discussion
Much of the technical background to ABE can be found in a research
paper [ABE2017]. This paper used a mix of experiments, theory and
simulations with NewReno [RFC5681] and CUBIC [RFC8312] to evaluate
the technique. The technique was shown to present "...significant
performance gains in lightly-multiplexed [few concurrent flows]
scenarios, without losing the delay-reduction benefits of deploying
CoDel or PIE". The performance improvement is achieved when reacting
to ECN-Echo in congestion avoidance (when ssthresh > cwnd) by
multiplying cwnd and ssthresh with a value in the range [0.7,0.85].
Applying ABE when cwnd <= ssthresh is not currently recommended, but
may benefit from additional attention, experimentation and
specification.
4.1. Why Use ECN to Vary the Degree of Backoff?
AQM mechanisms such as CoDel [RFC8289] and PIE [RFC8033] set a delay
target in routers and use congestion notifications to constrain the
queuing delays experienced by packets, rather than in response to
impending or actual bottleneck buffer exhaustion. With current
default delay targets, CoDel and PIE both effectively emulate a
bottleneck with a short queue (section II, [ABE2017]) while also
allowing short traffic bursts into the queue. This provides
acceptable performance for TCP connections over a path with a low
BDP, or in highly multiplexed scenarios (many concurrent transport
flows). However, in a lightly-multiplexed case over a path with a
large BDP, conventional TCP backoff leads to gaps in packet
transmission and under-utilisation of the path.
Instead of discarding packets, an AQM mechanism is allowed to mark
ECN-Capable packets with an ECN CE-mark. The reception of a CE-mark
feedback not only indicates congestion on the network path, it also
indicates that an AQM mechanism exists at the bottleneck along the
path, and hence the CE-mark likely came from a bottleneck with a
controlled short queue. Reacting differently to an ECN-signalled
congestion than to an inferred packet loss can then yield the benefit
of a reduced back-off when queues are short. Using ECN can also be
advantageous for several other reasons [RFC8087].
The idea of reacting differently to inferred packet loss and
detection of an ECN-signalled congestion pre-dates this
specification. For example, previous research proposed using ECN CE-
marked feedback to modify TCP congestion control behaviour via a
larger multiplicative decrease factor in conjunction with a smaller
additive increase factor [ICC2002]. The goal of this former work was
to operate across AQM bottlenecks using Random Early Detection (RED)
Khademi, et al. Expires March 18, 2019 [Page 6]
Internet-Draft ABE September 2018
that were not necessarily configured to emulate a short queue (The
current usage of RED as an Internet AQM method is limited [RFC7567]).
4.2. An RTT-based response to indicated congestion
This specification applies to the use of ECN feedback as defined in
[RFC3168], which specifies a response to indicated congestion that is
no more frequent that once per path round trip time. Since ABE
responds to indicated congestion once per RTT, it therefore does not
respond to any further loss within the same RTT, because an ABE
sender has already reduced the congestion window. If congestion
persists after such reduction, ABE continues to reduce the congestion
window in each consecutive RTT. This consecutive reduction can
protect the network against long-standing unfairness in the case of
AQM algorithms that do not keep a small average queue length. The
mechanism does not rely on Accurate ECN
([I-D.ietf-tcpm-accurate-ecn]).
In contrast, transport protocol mechanisms can also be designed to
utilise more frequent and detailed ECN feedback (e.g., Accurate ECN
[I-D.ietf-tcpm-accurate-ecn]), which then permit a congestion control
response that adjusts the sending rate more frequently. Datacenter
TCP (DCTCP) [RFC8257] is an example of this approach.
5. ABE Deployment Requirements
This update is a sender-side only change. Like other changes to
congestion control algorithms, it does not require any change to the
TCP receiver or to network devices. It does not require any ABE-
specific changes in routers or the use of Accurate ECN feedback
[I-D.ietf-tcpm-accurate-ecn] by a receiver.
If the method is only deployed by some senders, and not by others,
the senders that use this method can gain some advantage, possibly at
the expense of other flows that do not use this updated method.
Because this advantage applies only to ECN-marked packets and not to
packet loss indications, an ECN-Capable bottleneck will still fall
back to dropping packets if an TCP sender using ABE is too
aggressive, and the result is no different than if the TCP sender was
using traditional loss-based congestion control.
When used with bottlenecks that do not support ECN-marking the
specification does not modify the transport protocol.
Khademi, et al. Expires March 18, 2019 [Page 7]
Internet-Draft ABE September 2018
6. ABE Experiment Goals
[RFC3168] states that the congestion control response following an
indication of ECN-signalled congestion is the same as the response to
a dropped packet. [RFC8311] updates this specification to allow
systems to provide a different behaviour when they experience ECN-
signalled congestion rather than packet loss. The present
specification defines such an experiment and has thus been assigned
an Experimental status before being proposed as a Standards-Track
update.
The purpose of the Internet experiment is to collect experience with
deployment of ABE, and confirm acceptable safety in deployed networks
that use this update to TCP congestion control. To evaluate ABE,
this experiment therefore requires support in AQM routers for ECN-
marking of packets carrying the ECN-Capable Transport, ECT(0),
codepoint [RFC3168].
The result of this Internet experiment ought to include an
investigation of the implications of experiencing an ECN-CE mark
followed by loss within the same RTT. At the end of the experiment,
this will be reported to the TCPM WG or the IESG.
7. Acknowledgements
Authors N. Khademi, M. Welzl and G. Fairhurst were part-funded by
the European Community under its Seventh Framework Programme through
the Reducing Internet Transport Latency (RITE) project (ICT-317700).
The views expressed are solely those of the authors.
Author G. Armitage performed most of his work on this document while
employed by Swinburne University of Technology, Melbourne, Australia.
The authors would like to thank Stuart Cheshire for many suggestions
when revising the draft, and the following people for their
contributions to [ABE2017]: Chamil Kulatunga, David Ros, Stein
Gjessing, Sebastian Zander. Thanks also to (in alphabetical order)
Roland Bless, Bob Briscoe, David Black, Markku Kojo, John Leslie,
Lawrence Stewart, Dave Taht and the TCPM Working Group for providing
valuable feedback on this document.
The authors would finally like to thank everyone who provided
feedback on the congestion control behaviour specified in this update
received from the IRTF Internet Congestion Control Research Group
(ICCRG).
Khademi, et al. Expires March 18, 2019 [Page 8]
Internet-Draft ABE September 2018
8. IANA Considerations
XX RFC ED - PLEASE REMOVE THIS SECTION XXX
This document includes no request to IANA.
9. Implementation Status
ABE is implemented as a patch for Linux and FreeBSD. This is meant
for research and available for download from
http://heim.ifi.uio.no/michawe/research/abe/. This code was used to
produce the test results that are reported in [ABE2017]. The FreeBSD
code has been committed to the mainline kernel on March 19, 2018
[ABE-FreeBSD].
10. Security Considerations
The described method is a sender-side only transport change, and does
not change the protocol messages exchanged. The security
considerations for ECN [RFC3168] therefore still apply.
This is a change to TCP congestion control with ECN that will
typically lead to a change in the capacity achieved when flows share
a network bottleneck. This could result in some flows receiving more
than their fair share of capacity. Similar unfairness in the way
that capacity is shared is also exhibited by other congestion control
mechanisms that have been in use in the Internet for many years
(e.g., CUBIC [RFC8312]). Unfairness may also be a result of other
factors, including the round trip time experienced by a flow. ABE
applies only when ECN-marked packets are received, not when packets
are lost, hence use of ABE cannot lead to congestion collapse.
11. Revision Information
XX RFC ED - PLEASE REMOVE THIS SECTION XXX
-12. Corrections from Adam Roach; Benjamin Kaduk; & Ben Campbell
-10. Incorported changes following the Gen-ART review by Russ
Housley. Correction to URL.
-09. Changed to "Following publication of RFC 8311, this document
specifies a sender-side change to TCP:"
-08. Addressed comments from AD review on the document structure,
and relationship to existing RFCs.
-07. Addressed comments following WGLC.
Khademi, et al. Expires March 18, 2019 [Page 9]
Internet-Draft ABE September 2018
o Updated Reference citations.
o Removed paragraph containing a wrong statement related to timeout
in section 4.1.
o Discuss what happens when cwnd <= ssthresh.
o Added text on Concern about lower bound of 2*SMSS.
-06. Addressed Michael Scharf's comments.
-05. Refined the description of the experiment based on feedback at
IETF-100. Incorporated comments from David Black.
-04. Incorporates review comments from Lawrence Stewart and the
remaining comments from Roland Bless. References are updated.
-03. Several review comments from Roland Bless are addressed.
Consistent terminology and equations. Clarification on the scope of
recommended beta_{ecn} value.
-02. Corrected the equations in Section 3.1. Updated the
affiliations. Lower bound for cwnd is defined. A recommendation for
window-based transport protocols is changed to cover all transport
protocols that implement a congestion control reduction to an ECN
congestion signal. Added text about ABE's FreeBSD mainline kernel
status including a reference to the FreeBSD code review page.
References are updated.
-01. Text improved, mainly incorporating comments from Stuart
Cheshire. The reference to a technical report has been updated to a
published version of the tests [ABE2017]. Used "AQM Mechanism"
throughout in place of other alternatives, and more consistent use of
technical language and clarification on the intended purpose of the
experiments required by EXP status. There was no change to the
technical content.
-00. draft-ietf-tcpm-alternativebackoff-ecn-00 replaces draft-
khademi-tcpm-alternativebackoff-ecn-01. Text describing the nature
of the experiment was added.
Individual draft -01. This I-D now refers to draft-black-tsvwg-ecn-
experimentation-02, which replaces draft-khademi-tsvwg-ecn-
response-00 to make a broader update to RFC 3168 for the sake of
allowing experiments. As a result, some of the motivating and
discussing text that was moved from draft-khademi-alternativebackoff-
ecn-03 to draft-khademi-tsvwg-ecn-response-00 has now been re-
inserted here.
Khademi, et al. Expires March 18, 2019 [Page 10]
Internet-Draft ABE September 2018
Individual draft -00. draft-khademi-tsvwg-ecn-response-00 and draft-
khademi-tcpm-alternativebackoff-ecn-00 replace draft-khademi-
alternativebackoff-ecn-03, following discussion in the TSVWG and TCPM
working groups.
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP",
RFC 3168, DOI 10.17487/RFC3168, September 2001,
<https://www.rfc-editor.org/info/rfc3168>.
[RFC5681] Allman, M., Paxson, V., and E. Blanton, "TCP Congestion
Control", RFC 5681, DOI 10.17487/RFC5681, September 2009,
<https://www.rfc-editor.org/info/rfc5681>.
[RFC7567] Baker, F., Ed. and G. Fairhurst, Ed., "IETF
Recommendations Regarding Active Queue Management",
BCP 197, RFC 7567, DOI 10.17487/RFC7567, July 2015,
<https://www.rfc-editor.org/info/rfc7567>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8257] Bensley, S., Thaler, D., Balasubramanian, P., Eggert, L.,
and G. Judd, "Data Center TCP (DCTCP): TCP Congestion
Control for Data Centers", RFC 8257, DOI 10.17487/RFC8257,
October 2017, <https://www.rfc-editor.org/info/rfc8257>.
[RFC8311] Black, D., "Relaxing Restrictions on Explicit Congestion
Notification (ECN) Experimentation", RFC 8311,
DOI 10.17487/RFC8311, January 2018,
<https://www.rfc-editor.org/info/rfc8311>.
12.2. Informative References
[ABE-FreeBSD]
"ABE patch review in FreeBSD",
<https://svnweb.freebsd.org/
base?view=revision&revision=331214>.
Khademi, et al. Expires March 18, 2019 [Page 11]
Internet-Draft ABE September 2018
[ABE2017] Khademi, N., Armitage, G., Welzl, M., Fairhurst, G.,
Zander, S., and D. Ros, "Alternative Backoff: Achieving
Low Latency and High Throughput with ECN and AQM", IFIP
NETWORKING 2017, Stockholm, Sweden, June 2017.
[BUFFERBLOAT]
Gettys, J. and K. Nichols, "Bufferbloat: Dark Buffers in
the Internet", ACM Queue 9, 11, DOI
10.1145/2063166.2071893;
https://queue.acm.org/detail.cfm?id=2071893", November
2011.
[CODEL2012]
Nichols, K. and V. Jacobson, "Controlling Queue Delay",
July 2012, <http://queue.acm.org/detail.cfm?id=2209336>.
[I-D.ietf-tcpm-accurate-ecn]
Briscoe, B., Kuehlewind, M., and R. Scheffenegger, "More
Accurate ECN Feedback in TCP", draft-ietf-tcpm-accurate-
ecn-06 (work in progress), March 2018.
[ICC2002] Kwon, M. and S. Fahmy, "TCP Increase/Decrease Behavior
with Explicit Congestion Notification (ECN)", IEEE
ICC 2002, New York, New York, USA, May 2002,
<http://dx.doi.org/10.1109/ICC.2002.997262>.
[RFC8033] Pan, R., Natarajan, P., Baker, F., and G. White,
"Proportional Integral Controller Enhanced (PIE): A
Lightweight Control Scheme to Address the Bufferbloat
Problem", RFC 8033, DOI 10.17487/RFC8033, February 2017,
<https://www.rfc-editor.org/info/rfc8033>.
[RFC8087] Fairhurst, G. and M. Welzl, "The Benefits of Using
Explicit Congestion Notification (ECN)", RFC 8087,
DOI 10.17487/RFC8087, March 2017,
<https://www.rfc-editor.org/info/rfc8087>.
[RFC8289] Nichols, K., Jacobson, V., McGregor, A., Ed., and J.
Iyengar, Ed., "Controlled Delay Active Queue Management",
RFC 8289, DOI 10.17487/RFC8289, January 2018,
<https://www.rfc-editor.org/info/rfc8289>.
[RFC8312] Rhee, I., Xu, L., Ha, S., Zimmermann, A., Eggert, L., and
R. Scheffenegger, "CUBIC for Fast Long-Distance Networks",
RFC 8312, DOI 10.17487/RFC8312, February 2018,
<https://www.rfc-editor.org/info/rfc8312>.
Khademi, et al. Expires March 18, 2019 [Page 12]
Internet-Draft ABE September 2018
Authors' Addresses
Naeem Khademi
University of Oslo
PO Box 1080 Blindern
Oslo N-0316
Norway
Email: naeemk@ifi.uio.no
Michael Welzl
University of Oslo
PO Box 1080 Blindern
Oslo N-0316
Norway
Email: michawe@ifi.uio.no
Grenville Armitage
Netflix Inc.
Email: garmitage@netflix.com
Godred Fairhurst
University of Aberdeen
School of Engineering, Fraser Noble Building
Aberdeen AB24 3UE
UK
Email: gorry@erg.abdn.ac.uk
Khademi, et al. Expires March 18, 2019 [Page 13]
