draft-ietf-rmcat-eval-criteria-02.txt   draft-ietf-rmcat-eval-criteria-03.txt 
RMCAT WG V. Singh RMCAT WG V. Singh
Internet-Draft J. Ott Internet-Draft J. Ott
Intended status: Informational Aalto University Intended status: Informational Aalto University
Expires: January 26, 2015 July 25, 2014 Expires: September 11, 2015 March 10, 2015
Evaluating Congestion Control for Interactive Real-time Media Evaluating Congestion Control for Interactive Real-time Media
draft-ietf-rmcat-eval-criteria-02 draft-ietf-rmcat-eval-criteria-03
Abstract Abstract
The Real-time Transport Protocol (RTP) is used to transmit media in The Real-time Transport Protocol (RTP) is used to transmit media in
telephony and video conferencing applications. This document telephony and video conferencing applications. This document
describes the guidelines to evaluate new congestion control describes the guidelines to evaluate new congestion control
algorithms for interactive point-to-point real-time media. algorithms for interactive point-to-point real-time media.
Status of This Memo Status of This Memo
skipping to change at page 1, line 33 skipping to change at page 1, line 33
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-
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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 January 26, 2015. This Internet-Draft will expire on September 11, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. RTP Log Format . . . . . . . . . . . . . . . . . . . . . 4 3.1. RTP Log Format . . . . . . . . . . . . . . . . . . . . . 5
4. Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Avoiding Congestion Collapse . . . . . . . . . . . . . . 5 4.1. Avoiding Congestion Collapse . . . . . . . . . . . . . . 5
4.2. Stability . . . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Stability . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3. Media Traffic . . . . . . . . . . . . . . . . . . . . . . 5 4.3. Media Traffic . . . . . . . . . . . . . . . . . . . . . . 5
4.4. Start-up Behaviour . . . . . . . . . . . . . . . . . . . 6 4.4. Start-up Behaviour . . . . . . . . . . . . . . . . . . . 6
4.5. Diverse Environments . . . . . . . . . . . . . . . . . . 6 4.5. Diverse Environments . . . . . . . . . . . . . . . . . . 6
4.6. Varying Path Characteristics . . . . . . . . . . . . . . 6 4.6. Varying Path Characteristics . . . . . . . . . . . . . . 6
4.7. Reacting to Transient Events or Interruptions . . . . . . 6 4.7. Reacting to Transient Events or Interruptions . . . . . . 7
4.8. Fairness With Similar Cross-Traffic . . . . . . . . . . . 7 4.8. Fairness With Similar Cross-Traffic . . . . . . . . . . . 7
4.9. Impact on Cross-Traffic . . . . . . . . . . . . . . . . . 7 4.9. Impact on Cross-Traffic . . . . . . . . . . . . . . . . . 7
4.10. Extensions to RTP/RTCP . . . . . . . . . . . . . . . . . 7 4.10. Extensions to RTP/RTCP . . . . . . . . . . . . . . . . . 7
5. Minimum Requirements for Evaluation . . . . . . . . . . . . . 7 5. List of Network Parameters . . . . . . . . . . . . . . . . . 7
6. Status of Proposals . . . . . . . . . . . . . . . . . . . . . 7 5.1. One-way Propagation Delay . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5.2. End-to-end Loss . . . . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5.3. DropTail Router Queue Length . . . . . . . . . . . . . . 8
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 5.4. Loss generation model . . . . . . . . . . . . . . . . . . 8
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 5.5. Jitter models . . . . . . . . . . . . . . . . . . . . . . 9
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.5.1. Random Bounded PDV (RBPDV) . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 8 5.5.2. Approximately Random Subject to No-Reordering Bounded
11.2. Informative References . . . . . . . . . . . . . . . . . 9 PDV (NR-RPVD) . . . . . . . . . . . . . . . . 10
Appendix A. Application Trade-off . . . . . . . . . . . . . . . 10 6. Traffic Models . . . . . . . . . . . . . . . . . . . . . . . 11
A.1. Measuring Quality . . . . . . . . . . . . . . . . . . . . 10 6.1. TCP taffic model . . . . . . . . . . . . . . . . . . . . 11
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 10 6.2. RTP Video model . . . . . . . . . . . . . . . . . . . . . 12
B.1. Changes in draft-ietf-rmcat-eval-criteria-02 . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
B.2. Changes in draft-ietf-rmcat-eval-criteria-01 . . . . . . 10 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
B.3. Changes in draft-ietf-rmcat-eval-criteria-00 . . . . . . 10 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12
B.4. Changes in draft-singh-rmcat-cc-eval-04 . . . . . . . . . 10 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
B.5. Changes in draft-singh-rmcat-cc-eval-03 . . . . . . . . . 11 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
B.6. Changes in draft-singh-rmcat-cc-eval-02 . . . . . . . . . 11 11.1. Normative References . . . . . . . . . . . . . . . . . . 12
B.7. Changes in draft-singh-rmcat-cc-eval-01 . . . . . . . . . 11 11.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Appendix A. Application Trade-off . . . . . . . . . . . . . . . 14
A.1. Measuring Quality . . . . . . . . . . . . . . . . . . . . 14
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 14
B.1. Changes in draft-ietf-rmcat-eval-criteria-02 . . . . . . 14
B.2. Changes in draft-ietf-rmcat-eval-criteria-02 . . . . . . 14
B.3. Changes in draft-ietf-rmcat-eval-criteria-01 . . . . . . 14
B.4. Changes in draft-ietf-rmcat-eval-criteria-00 . . . . . . 15
B.5. Changes in draft-singh-rmcat-cc-eval-04 . . . . . . . . . 15
B.6. Changes in draft-singh-rmcat-cc-eval-03 . . . . . . . . . 15
B.7. Changes in draft-singh-rmcat-cc-eval-02 . . . . . . . . . 15
B.8. Changes in draft-singh-rmcat-cc-eval-01 . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
This memo describes the guidelines to help with evaluating new This memo describes the guidelines to help with evaluating new
congestion control algorithms for interactive point-to-point real congestion control algorithms for interactive point-to-point real
time media. The requirements for the congestion control algorithm time media. The requirements for the congestion control algorithm
are outlined in [I-D.ietf-rmcat-cc-requirements]). This document are outlined in [I-D.ietf-rmcat-cc-requirements]). This document
builds upon previous work at the IETF: Specifying New Congestion builds upon previous work at the IETF: Specifying New Congestion
Control Algorithms [RFC5033] and Metrics for the Evaluation of Control Algorithms [RFC5033] and Metrics for the Evaluation of
Congestion Control Algorithms [RFC5166]. Congestion Control Algorithms [RFC5166].
The guidelines proposed in the document are intended to help prevent The guidelines proposed in the document are intended to help prevent
a congestion collapse, promote fair capacity usage and optimize the a congestion collapse, promote fair capacity usage and optimize the
media flow's throughput. Furthermore, the proposed algorithms are media flow's throughput. Furthermore, the proposed algorithms are
expected to operate within the envelope of the circuit breakers expected to operate within the envelope of the circuit breakers
defined in [I-D.ietf-avtcore-rtp-circuit-breakers]. defined in [I-D.ietf-avtcore-rtp-circuit-breakers].
This document only provides broad-level criteria for evaluating a new This document only provides broad-level criteria for evaluating a new
congestion control algorithm and the working group should expect a congestion control algorithm. The minimal requirement for RMCAT
thorough scientific study to make its decision. The results of the proposals is to produce or present results for the test scenarios
evaluation are not expected to be included within the internet-draft described in [I-D.ietf-rmcat-eval-test] (Basic Test Cases). The
but should be cited in the document. results of the evaluation are not expected to be included within the
internet-draft but should be cited in the document.
2. Terminology 2. Terminology
The terminology defined in RTP [RFC3550], RTP Profile for Audio and The terminology defined in RTP [RFC3550], RTP Profile for Audio and
Video Conferences with Minimal Control [RFC3551], RTCP Extended Video Conferences with Minimal Control [RFC3551], RTCP Extended
Report (XR) [RFC3611], Extended RTP Profile for RTCP-based Feedback Report (XR) [RFC3611], Extended RTP Profile for RTCP-based Feedback
(RTP/AVPF) [RFC4585] and Support for Reduced-Size RTCP [RFC5506] (RTP/AVPF) [RFC4585] and Support for Reduced-Size RTCP [RFC5506]
apply. apply.
3. Metrics 3. Metrics
[RFC5166] describes the basic metrics for congestion control.
Metrics that are of interest for interactive multimedia are:
o Throughput.
o Minimizing oscillations in the transmission rate (stability) when
the end-to-end capacity varies slowly.
o Delay.
o Reactivity to transient events.
o Packet losses and discards.
o Section 2.1 of [RFC5166] discusses the tradeoff between
throughput, delay and loss.
Each experiment is expected to log every incoming and outgoing packet Each experiment is expected to log every incoming and outgoing packet
(the RTP logging format is described in Section 3.1). The logging (the RTP logging format is described in Section 3.1). The logging
can be done inside the application or at the endpoints using pcap can be done inside the application or at the endpoints using PCAP
(packet capture, e.g., tcpdump, wireshark). The following are (packet capture, e.g., tcpdump, wireshark). The following are
calculated based on the information in the packet logs: calculated based on the information in the packet logs:
1. Sending rate, Receiver rate, Goodput 1. Sending rate, Receiver rate, Goodput (measured at 200ms
intervals)
2. Packet delay 2. Packets sent, Packets received
3. Packet loss
4. If using, retransmission or FEC: residual loss 3. Bytes sent, bytes received
5. Packets discarded from the playout or de-jitter buffer 4. Packet delay
5. Packets lost, Packets discarded (from the playout or de-jitter
buffer)
6. Fairness or Unfairness: Experiments testing the performance of an 6. If using, retransmission or FEC: post-repair loss
RMCAT proposal against any cross-traffic must define its expected
criteria for fairness. The "unfairness" test guideline (measured
at 1s intervals) is:
1. Does not trigger the circuit breaker.
2. No RMCAT stream achieves more than 3 times the average
throughput of the RMCAT stream with the lowest average
throughput, for a case when the competing streams have similar
RTTs.
3. RTT should not grow by a factor of 3 for the existing flows
when a new flow is added.
For example, see the test scenarios described in
[I-D.sarker-rmcat-eval-test].
7. Convergence time: The time taken to reach a stable rate at 7. Fairness or Unfairness: Experiments testing the performance of
startup, after the available link capacity changes, or when new an RMCAT proposal against any cross-traffic must define its
flows get added to the bottleneck link. expected criteria for fairness. The "unfairness" test guideline
(measured at 1s intervals) is:
1. Does not trigger the circuit breaker.
2. No RMCAT stream achieves more than 3 times the average
throughput of the RMCAT stream with the lowest average
throughput, for a case when the competing streams have similar
RTTs.
3. RTT should not grow by a factor of 3 for the existing flows
when a new flow is added.
For example, see the test scenarios described in
[I-D.ietf-rmcat-eval-test].
8. Bandwidth Utilization, defined as ratio of the instantaneous 8. Convergence time: The time taken to reach a stable rate at
sending rate to the instantaneous bottleneck capacity. This startup, after the available link capacity changes, or when new
metric is useful when an RMCAT flow is by itself or competing flows get added to the bottleneck link.
with similar cross-traffic.
9. Instability or oscillation in the sending rate: The frequency or
number of instances when the sending rate oscillates between an
high watermark level and a low watermark level, or vice-versa in
a defined time window. For example, the watermarks can be set
at 4x interval: 500 Kbps, 2 Mbps, and a time window of 500ms.
10. Bandwidth Utilization, defined as ratio of the instantaneous
sending rate to the instantaneous bottleneck capacity. This
metric is useful only when an RMCAT flow is by itself or
competing with similar cross-traffic.
From the logs the statistical measures (min, max, mean, standard From the logs the statistical measures (min, max, mean, standard
deviation and variance) for the whole duration or any specific part deviation and variance) for the whole duration or any specific part
of the session can be calculated. Also the metrics (sending rate, of the session can be calculated. Also the metrics (sending rate,
receiver rate, goodput, latency) can be visualized in graphs as receiver rate, goodput, latency) can be visualized in graphs as
variation over time, the measurements in the plot are at 1 second variation over time, the measurements in the plot are at 1 second
intervals. Additionally, from the logs it is possible to plot the intervals. Additionally, from the logs it is possible to plot the
histogram or CDF of packet delay. histogram or CDF of packet delay.
[Open issue (1): Using Jain-fairness index (JFI) for measuring self- [Open issue (1): Using Jain-fairness index (JFI) for measuring self-
skipping to change at page 7, line 33 skipping to change at page 7, line 39
The proposal should also measure the impact on varied number of The proposal should also measure the impact on varied number of
cross-traffic sources, i.e., few and many competing flows, or mixing cross-traffic sources, i.e., few and many competing flows, or mixing
various amounts of TCP and similar cross-traffic. various amounts of TCP and similar cross-traffic.
4.10. Extensions to RTP/RTCP 4.10. Extensions to RTP/RTCP
The congestion control algorithm should indicate if any protocol The congestion control algorithm should indicate if any protocol
extensions are required to implement it and should carefully describe extensions are required to implement it and should carefully describe
the impact of the extension. the impact of the extension.
5. Minimum Requirements for Evaluation 5. List of Network Parameters
The minimal requirements for RMCAT proposals is to produce or present The implementors initially are encouraged to choose evaluation
results for the test scenarios described in Section 5 of settings from the following values:
[I-D.sarker-rmcat-eval-test] (Basic Test Cases).
6. Status of Proposals 5.1. One-way Propagation Delay
Congestion control algorithms are expected to be published as Experiments are expected to verify that the congestion control is
"Experimental" documents until they are shown to be safe to deploy. able to work in challenging situations, for example over trans-
An algorithm published as a draft should be experimented in continental and/or satellite links. Typical values are:
simulation, or a controlled environment (testbed) to show its
applicability. Every congestion control algorithm should include a
note describing the environments in which the algorithm is tested and
safe to deploy. It is possible that an algorithm is not recommended
for certain environments or perform sub-optimally for the user.
[Editor's Note: Should there be a distinction between "Informational" 1. Very low latency: 0-1ms
and "Experimental" drafts for congestion control algorithms in RMCAT.
[RFC5033] describes Informational proposals as algorithms that are 2. Low latency: 50ms
not safe for deployment but are proposals to experiment with in 3. High latency: 150ms
simulation/testbeds. While Experimental algorithms are ones that are
deemed safe in some environments but require a more thorough 4. Extreme latency: 300ms
evaluation (from the community).]
5.2. End-to-end Loss
To model lossy links, the experiments can choose one of the following
loss rates, the fractional loss is the ratio of packets lost and
packets sent.
1. no loss: 0%
2. 1%
3. 5%
4. 10%
5. 20%
5.3. DropTail Router Queue Length
The router queue length is measured as the time taken to drain the
FIFO queue. It has been noted in various discussions that the queue
length in the current deployed Internet varies significantly. While
the core backbone network has very short queue length, the home
gateways usually have larger queue length. Those various queue
lengths can be categorized in the following way:
1. QoS-aware (or short): 70ms
2. Nominal: 300-500ms
3. Buffer-bloated: 1000-2000ms
Here the size of the queue is measured in bytes or packets and to
convert the queue length measured in seconds to queue length in
bytes:
QueueSize (in bytes) = QueueSize (in sec) x Throughput (in bps)/8
5.4. Loss generation model
[Editor's note : Describes the model for generating packet losses,
for example, losses can be generated using traces, or using the
Gilbert-Elliot model, or randomly (uncorrelated loss).]
5.5. Jitter models
This section defines jitter model for the purposes of this document.
When jitter is to be applied to both the RMCAT flow and any competing
flow (such as a TCP competing flow), the competing flow will use the
jitter definition below that does not allow for re-ordering of
packets on the competing flow (see NR-RBPDV definition below).
Jitter is an overloaded term in communications. Its meaning is
typically associated with the variation of a metric (e.g., delay)
with respect to some reference metric (e.g., average delay or minimum
delay). For example, RFC 3550 jitter is a smoothed estimate of
jitter which is particularly meaningful if the underlying packet
delay variation was caused by a Gaussian random process.
Because jitter is an overloaded term, we instead use the term Packet
Delay Variation (PDV) to describe the variation of delay of
individual packets in the same sense as the IETF IPPM WG has defined
PDV in their documents (e.g., RFC 3393) and as the ITU-T SG16 has
defined IP Packet Delay Variation (IPDV) in their documents (e.g.,
Y.1540).
Most PDV distributions in packet network systems are one-sided
distributions (the measurement of which with a finite number of
measurement samples result in one-sided histograms). In the usual
packet network transport case there is typically one packet that
transited the network with the minimum delay, then a majority of
packets also transit the system within some variation from this
minimum delay, and then a minority of the packets transits the
network with delays higher than the median or average transit time
(these are outliers). Although infrequent, outliers can cause
significant deleterious operation in adaptive systems and should be
considered in RMCAT adaptation designs.
In this section we define two different bounded PDV characteristics,
1) Random Bounded PDV and 2) Approximately Random Subject to No-
Reordering Bounded PDV.
5.5.1. Random Bounded PDV (RBPDV)
The RBPDV probability distribution function (pdf) is specified to be
of some mathematically describable function which includes some
practical minimum and maximum discrete values suitable for testing.
For example, the minimum value, x_min, might be specified as the
minimum transit time packet and the maximum value, x_max, might be
idefined to be two standard deviations higher than the mean.
Since we are typically interested in the distribution relative to the
mean delay packet, we define the zero mean PVD sample, z(n), to be
z(n) = x(n) - x_mean, where x(n) is a sample of the RBPDV random
variable x and x_mean is the mean of x.
We assume here that s(n) is the original source time of packet n and
the post-jitter induced emmission time, j(n), for packet n is j(n) =
{[z(n) + x_mean] + s(n)}. It follows that the separation in the post-
jitter time of packets n and n+1 is {[s(n+1)-s(n)] - [z(n)-z(n+1)]}.
Since the first term is always a positive quantity, we note that
packet reordering at the receiver is possible whenever the second
term is greater than the first. Said another way, whenever the
difference in possible zero mean PDV sample delays (i.e., [x_max-
x_min]) exceeds the inter-departure time of any two sent packets, we
have the possibility of packet re-ordering.
There are important use cases in real networks where packets can
become re-ordered such as in load balancing topologies and during
route changes. However, for the vast majority of cases there is no
packet re-ordering because most of the time packets follow the same
path. Due to this, if a packet becomes overly delayed, the packets
after it on that flow are also delayed. This is especially true for
mobile wireless links where there are per-flow queues prior to base
station scheduling. Owing to this important use case, we define
another PDV profile similar to the above, but one that does not allow
for re-ordering within a flow.
5.5.2. Approximately Random Subject to No-Reordering Bounded PDV (NR-
RPVD)
No Reordering RPDV, NR-RPVD, is defined similarly to the above with
one important exception. Let serial(n) be defined as the
serialization delay of packet n at the lowest bottleneck link rate
(or other appropriate rate) in a given test. Then we produce all the
post-jitter values for j(n) for n = 1, 2, ... N, where N is the
length of the source sequence s to be offset-ed. The exception can
be stated as follows: We revisit all j(n) beginning from index n=2,
and if j(n) is determined to be less than [j(n-1)+serial(n-1)], we
redefine j(n) to be equal to [j(n-1)+serial(n-1)] and continue for
all remaining n (i.e., n = 3, 4, .. N). This models the case where
the packet n is sent immediately after packet (n-1) at the bottleneck
link rate. Although this is generally the theoretical minimum in
that it assumes that no other packets from other flows are in-between
packet n and n+1 at the bottleneck link, it is a reasonable
assumption for per flow queuing.
We note that this assumption holds for some important exception
cases, such as packets immediately following outliers. There are a
multitude of software controlled elements common on end-to-end
Internet paths (such as firewalls, ALGs and other middleboxes) which
stop processing packets while servicing other functions (e.g.,
garbage collection). Often these devices do not drop packets, but
rather queue them for later processing and cause many of the
outliers. Thus NR-RPVD models this particular use case (assuming
serial(n+1) is defined appropriately for the device causing the
outlier) and thus is believed to be important for adaptation
development for RMCAT.
[Editor's Note: It may require to define test distributions as well.
Example test distribution may include-
1 - Two-sided: Uniform PDV Distribution. Two quantities to define:
x_min and x_max.
2 - Two-sided: Truncated Gaussian PDV Distribution. Four quantities
to define: the appropriate x_min and x_max for test (e.g., +/- two
sigma values), the standard deviation and the mean.
3 - One Sided: TBD]
6. Traffic Models
6.1. TCP taffic model
Long-lived TCP flows will download data throughout the session and
are expected to have infinite amount of data to send or receive.
Each short TCP flow is modeled as a sequence of file downloads
interleaved with idle periods. Not all short TCPs start at the same
time, i.e., some start in the ON state while others start in the OFF
state.
The short TCP flows can be modelled in two ways, 1) 100s of flows
fetching small (5-20 KB) amounts of data, or 2) 10s of flows fetching
slightly larger (100-1000KB) amounts of data.
The idle period is typically derived from an exponential distribution
with the mean value of 10 seconds.
[Open issue: short-lived/bursty TCP cross-traffic parameters are
still to be agreed upon].
6.2. RTP Video model
[I-D.zhu-rmcat-video-traffic-source] describes two types of video
traffic models for evaluating RMCAT candidate algorithms. The first
model statistically characterizes the behavior of a video encoder.
Whereas the second model uses video traces.
7. Security Considerations 7. Security Considerations
Security issues have not been discussed in this memo. Security issues have not been discussed in this memo.
8. IANA Considerations 8. IANA Considerations
There are no IANA impacts in this memo. There are no IANA impacts in this memo.
9. Contributors 9. Contributors
The content and concepts within this document are a product of the The content and concepts within this document are a product of the
discussion carried out in the Design Team. discussion carried out in the Design Team.
Michael Ramalho provided the text for a specific scenario, which is Michael Ramalho provided the text for the Jitter model.
now covered in [I-D.sarker-rmcat-eval-test].
10. Acknowledgements 10. Acknowledgements
Much of this document is derived from previous work on congestion Much of this document is derived from previous work on congestion
control at the IETF. control at the IETF.
The authors would like to thank Harald Alvestrand, Anna Brunstrom, The authors would like to thank Harald Alvestrand, Anna Brunstrom,
Luca De Cicco, Wesley Eddy, Lars Eggert, Kevin Gross, Vinayak Hegde, Luca De Cicco, Wesley Eddy, Lars Eggert, Kevin Gross, Vinayak Hegde,
Stefan Holmer, Randell Jesup, Karen Nielsen, Piers O'Hanlon, Colin Stefan Holmer, Randell Jesup, Mirja Kuehlewind, Karen Nielsen, Piers
Perkins, Michael Ramalho, Zaheduzzaman Sarker, Timothy B. Terriberry, O'Hanlon, Colin Perkins, Michael Ramalho, Zaheduzzaman Sarker,
Michael Welzl, and Mo Zanaty for providing valuable feedback on Timothy B. Terriberry, Michael Welzl, and Mo Zanaty for providing
earlier versions of this draft. Additionally, also thank the valuable feedback on earlier versions of this draft. Additionally,
participants of the design team for their comments and discussion also thank the participants of the design team for their comments and
related to the evaluation criteria. discussion related to the evaluation criteria.
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
skipping to change at page 9, line 19 skipping to change at page 13, line 19
[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control "Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July
2006. 2006.
[RFC5506] Johansson, I. and M. Westerlund, "Support for Reduced-Size [RFC5506] Johansson, I. and M. Westerlund, "Support for Reduced-Size
Real-Time Transport Control Protocol (RTCP): Opportunities Real-Time Transport Control Protocol (RTCP): Opportunities
and Consequences", RFC 5506, April 2009. and Consequences", RFC 5506, April 2009.
[I-D.ietf-rmcat-cc-requirements] [I-D.ietf-rmcat-cc-requirements]
Jesup, R., "Congestion Control Requirements For RMCAT", Jesup, R. and Z. Sarker, "Congestion Control Requirements
draft-ietf-rmcat-cc-requirements-02 (work in progress), for Interactive Real-Time Media", draft-ietf-rmcat-cc-
February 2014. requirements-09 (work in progress), December 2014.
[I-D.ietf-avtcore-rtp-circuit-breakers] [I-D.ietf-avtcore-rtp-circuit-breakers]
Perkins, C. and V. Singh, "Multimedia Congestion Control: Perkins, C. and V. Singh, "Multimedia Congestion Control:
Circuit Breakers for Unicast RTP Sessions", draft-ietf- Circuit Breakers for Unicast RTP Sessions", draft-ietf-
avtcore-rtp-circuit-breakers-05 (work in progress), avtcore-rtp-circuit-breakers-09 (work in progress), March
February 2014. 2015.
11.2. Informative References 11.2. Informative References
[RFC5033] Floyd, S. and M. Allman, "Specifying New Congestion [RFC5033] Floyd, S. and M. Allman, "Specifying New Congestion
Control Algorithms", BCP 133, RFC 5033, August 2007. Control Algorithms", BCP 133, RFC 5033, August 2007.
[RFC5166] Floyd, S., "Metrics for the Evaluation of Congestion [RFC5166] Floyd, S., "Metrics for the Evaluation of Congestion
Control Mechanisms", RFC 5166, March 2008. Control Mechanisms", RFC 5166, March 2008.
[RFC5681] Allman, M., Paxson, V., and E. Blanton, "TCP Congestion [RFC5681] Allman, M., Paxson, V., and E. Blanton, "TCP Congestion
Control", RFC 5681, September 2009. Control", RFC 5681, September 2009.
[I-D.sarker-rmcat-eval-test] [I-D.ietf-rmcat-eval-test]
Sarker, Z., Singh, V., Zhu, X., and M. Ramalho, "Test Sarker, Z., Singh, V., Zhu, X., and M. Ramalho, "Test
Cases for Evaluating RMCAT Proposals", draft-sarker-rmcat- Cases for Evaluating RMCAT Proposals", draft-ietf-rmcat-
eval-test-00 (work in progress), February 2014. eval-test-00 (work in progress), August 2014.
[I-D.zhu-rmcat-video-traffic-source]
Zhu, X., Cruz, S., and Z. Sarker, "Modeling Video Traffic
Sources for RMCAT Evaluations", draft-zhu-rmcat-video-
traffic-source-00 (work in progress), October 2014.
[SA4-EVAL] [SA4-EVAL]
R1-081955, 3GPP., "LTE Link Level Throughput Data for SA4 R1-081955, 3GPP., "LTE Link Level Throughput Data for SA4
Evaluation Framework", 3GPP R1-081955, 5 2008. Evaluation Framework", 3GPP R1-081955, 5 2008.
[SA4-LR] S4-050560, 3GPP., "Error Patterns for MBMS Streaming over [SA4-LR] S4-050560, 3GPP., "Error Patterns for MBMS Streaming over
UTRAN and GERAN", 3GPP S4-050560, 5 2008. UTRAN and GERAN", 3GPP S4-050560, 5 2008.
[TCP-eval-suite] [TCP-eval-suite]
Lachlan, A., Marcondes, C., Floyd, S., Dunn, L., Guillier, Lachlan, A., Marcondes, C., Floyd, S., Dunn, L., Guillier,
skipping to change at page 10, line 32 skipping to change at page 14, line 35
interactive video by performing analysis using a real codec and video interactive video by performing analysis using a real codec and video
sequences. sequences.
Appendix B. Change Log Appendix B. Change Log
Note to the RFC-Editor: please remove this section prior to Note to the RFC-Editor: please remove this section prior to
publication as an RFC. publication as an RFC.
B.1. Changes in draft-ietf-rmcat-eval-criteria-02 B.1. Changes in draft-ietf-rmcat-eval-criteria-02
o Keep-alive version.
o Moved link parameters and traffic models from eval-test
B.2. Changes in draft-ietf-rmcat-eval-criteria-02
o Incorporated fairness test as a working test. o Incorporated fairness test as a working test.
o Updated text on mimimum evaluation requirements. o Updated text on mimimum evaluation requirements.
B.2. Changes in draft-ietf-rmcat-eval-criteria-01 B.3. Changes in draft-ietf-rmcat-eval-criteria-01
o Removed Appendix B. o Removed Appendix B.
o Removed Section on Evaluation Parameters. o Removed Section on Evaluation Parameters.
B.3. Changes in draft-ietf-rmcat-eval-criteria-00 B.4. Changes in draft-ietf-rmcat-eval-criteria-00
o Updated references. o Updated references.
o Resubmitted as WG draft. o Resubmitted as WG draft.
B.4. Changes in draft-singh-rmcat-cc-eval-04 B.5. Changes in draft-singh-rmcat-cc-eval-04
o Incorporate feedback from IETF 87, Berlin. o Incorporate feedback from IETF 87, Berlin.
o Clarified metrics: convergence time, bandwidth utilization. o Clarified metrics: convergence time, bandwidth utilization.
o Changed fairness criteria to fairness test. o Changed fairness criteria to fairness test.
o Added measuring pre- and post-repair loss. o Added measuring pre- and post-repair loss.
o Added open issue of measuring video quality to appendix. o Added open issue of measuring video quality to appendix.
o clarified use of DropTail and AQM. o clarified use of DropTail and AQM.
o Updated text in "Minimum Requirements for Evaluation" o Updated text in "Minimum Requirements for Evaluation"
B.5. Changes in draft-singh-rmcat-cc-eval-03 B.6. Changes in draft-singh-rmcat-cc-eval-03
o Incorporate the discussion within the design team. o Incorporate the discussion within the design team.
o Added a section on evaluation parameters, it describes the flow o Added a section on evaluation parameters, it describes the flow
and network characteristics. and network characteristics.
o Added Appendix with self-fairness experiment. o Added Appendix with self-fairness experiment.
o Changed bottleneck parameters from a proposal to an example set. o Changed bottleneck parameters from a proposal to an example set.
o o
B.6. Changes in draft-singh-rmcat-cc-eval-02 B.7. Changes in draft-singh-rmcat-cc-eval-02
o Added scenario descriptions. o Added scenario descriptions.
B.7. Changes in draft-singh-rmcat-cc-eval-01 B.8. Changes in draft-singh-rmcat-cc-eval-01
o Removed QoE metrics. o Removed QoE metrics.
o Changed stability to steady-state. o Changed stability to steady-state.
o Added measuring impact against few and many flows. o Added measuring impact against few and many flows.
o Added guideline for idle and data-limited periods. o Added guideline for idle and data-limited periods.
o Added reference to TCP evaluation suite in example evaluation o Added reference to TCP evaluation suite in example evaluation
 End of changes. 37 change blocks. 
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