rfc8869xml2.original.xml   rfc8869.xml 
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<rfc category="info" docName="draft-ietf-rmcat-wireless-tests-11"
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docName="draft-ietf-rmcat-wireless-tests-11"
number="8869"
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<front> <front>
<!-- The abbreviated title is used in the page header - it is only necessary
if the
full title is longer than 39 characters -->
<title abbrev="RMCAT Wireless Test Cases">Evaluation Test Cases for <title abbrev="Wireless Test Cases for Interactive Real-Time Media">
Evaluation Test Cases for
Interactive Real-Time Media over Wireless Networks</title> Interactive Real-Time Media over Wireless Networks</title>
<seriesInfo name="RFC" value="8869"/>
<author fullname="Zaheduzzaman Sarker" initials="Z." surname="Sarker"> <author fullname="Zaheduzzaman Sarker" initials="Z." surname="Sarker">
<organization>Ericsson AB</organization> <organization>Ericsson AB</organization>
<address> <address>
<postal> <postal>
<street>Laboratoriegr&auml;nd 11</street> <street>Torshamnsgatan 23</street>
<city>Lule&aring;</city> <city>Stockholm</city>
<region></region> <code>164 83</code>
<code>97753</code> <country>Sweden</country>
<country>Sweden</country>
</postal> </postal>
<phone>+46 10 717 37 43</phone>
<phone>+46 107173743</phone>
<email>zaheduzzaman.sarker@ericsson.com</email> <email>zaheduzzaman.sarker@ericsson.com</email>
</address> </address>
</author> </author>
<!--
<author fullname="Ingemar Johansson" initials="I." surname="Johansson">
<organization>Ericsson AB</organization>
<address>
<postal>
<street>Laboratoriegr&auml;nd 11</street>
<city>Lule&aring;</city>
<region></region>
<code>97753</code>
<country>Sweden</country>
</postal>
<phone>+46 10 7143042</phone>
<email>ingemar.s.johansson@ericsson.com</email>
</address>
</author>
-->
<author fullname="Xiaoqing Zhu" initials="X" surname="Zhu"> <author fullname="Xiaoqing Zhu" initials="X" surname="Zhu">
<organization>Cisco Systems</organization> <organization>Cisco Systems</organization>
<address> <address>
<postal> <postal>
<street>12515 Research Blvd., Building 4</street> <extaddr>Building 4</extaddr>
<city>Austin</city> <street>12515 Research Blvd</street>
<region>TX</region> <city>Austin</city>
<code>78759</code> <region>TX</region>
<country>USA</country> <code>78759</code>
<country>United States of America</country>
</postal> </postal>
<email>xiaoqzhu@cisco.com</email> <email>xiaoqzhu@cisco.com</email>
</address> </address>
</author> </author>
<author fullname="Jiantao Fu" initials="J." surname="Fu"> <author fullname="Jiantao Fu" initials="J." surname="Fu">
<organization>Cisco Systems</organization> <organization>Cisco Systems</organization>
<address> <address>
<postal> <postal>
<street>771 Alder Drive</street> <street>771 Alder Drive</street>
<city>Milpitas</city> <city>Milpitas</city>
<region>CA</region> <region>CA</region>
<code>95035</code> <code>95035</code>
<country>USA</country> <country>United States of America</country>
</postal> </postal>
<email>jianfu@cisco.com</email> <email>jianfu@cisco.com</email>
</address> </address>
</author> </author>
<!-- <date year="2021" month="January"/>
<author fullname="Wei-Tian Tan" initials="W.-T." surname="Tan">
<organization>Cisco Systems</organization>
<address>
<postal>
<street>510 McCarthy Blvd</street>
<city>Milpitas</city>
<region>CA</region>
<code>95035</code>
<country>USA</country>
</postal>
<email>dtan2@cisco.com</email>
</address>
</author>
<author fullname="Michael A. Ramalho" initials="M. A." surname="Ramalho">
<organization abbrev="AcousticComms">AcousticComms Consulting</organizatio
n>
<address>
<postal>
<street>6310 Watercrest Way Unit 203</street>
<city>Lakewood Ranch</city>
<region>FL</region>
<code>34202-5211</code>
<country>USA</country>
</postal>
<phone>+1 732 832 9723</phone>
<email>mar42@cornell.edu</email>
</address>
</author>
-->
<date year="2020" />
<!-- Meta-data Declarations -->
<area>TSV</area> <area>TSV</area>
<keyword>Cellular Network</keyword> <keyword>Cellular Network</keyword>
<keyword>Wi-Fi Network</keyword> <keyword>Wi-Fi Network</keyword>
<keyword>Congestion Control</keyword> <keyword>Congestion Control</keyword>
<keyword>RTP</keyword> <keyword>RTP</keyword>
<abstract> <abstract>
<t>The Real-time Transport Protocol (RTP) is a common transport choice for
<t>The Real-time Transport Protocol (RTP) is a common transport choice for
interactive multimedia communication applications. The performance of thes e interactive multimedia communication applications. The performance of thes e
applications typically depends on a well-functioning congestion control al gorithm. applications typically depends on a well-functioning congestion control al gorithm.
To ensure a seamless and robust user experience, a well-designed RTP-based To ensure a seamless and robust user experience, a well-designed RTP-based
congestion control algorithm should work well across all access network ty pes. congestion control algorithm should work well across all access network ty pes.
This document describes test cases for evaluating performances of candidat e This document describes test cases for evaluating performances of candidat e
congestion control algorithms over cellular and Wi-Fi networks.</t> congestion control algorithms over cellular and Wi-Fi networks.</t>
</abstract> </abstract>
</front> </front>
<middle> <middle>
<section numbered="true" toc="default">
<section title="Introduction"> <name>Introduction</name>
<t>Wireless networks (both cellular and Wi-Fi <xref target="IEEE802.11" fo
<t>Wireless networks (both cellular and Wi-Fi <xref target="IEEE802.11"></xref rmat="default"/>)
>)
are an integral and increasingly more significant part of the Internet. Typica l are an integral and increasingly more significant part of the Internet. Typica l
application scenarios for interactive multimedia communication over wireless i nclude application scenarios for interactive multimedia communication over wireless i nclude
from video conferencing calls in a bus or train as well as live media streamin g at home. video conferencing calls in a bus or train as well as live media streaming at home.
It is well known that the characteristics and technical challenges for support ing It is well known that the characteristics and technical challenges for support ing
multimedia services over wireless are very different from those of providing t he multimedia services over wireless are very different from those of providing t he
same service over a wired network. Although the basic test cases as defined in same service over a wired network. Although the basic test cases as defined in
<xref target="I-D.ietf-rmcat-eval-test"></xref> have covered many common effec ts of <xref target="RFC8867" format="default"/> have covered many common effects of
network impairments for evaluating RTP-based congestion control schemes, they remain network impairments for evaluating RTP-based congestion control schemes, they remain
to be tested over characteristics and dynamics unique to a given wireless envi ronment. to be tested over characteristics and dynamics unique to a given wireless envi ronment.
For example, in cellular networks, the base station maintains individual queue s per For example, in cellular networks, the base station maintains individual queue s per
radio bearer per user hence it leads to a different nature of interactions bet ween radio bearer per user hence it leads to a different nature of interactions bet ween
traffic flows of different users. This contrasts with a typical wired network setting traffic flows of different users. This contrasts with a typical wired network setting
where traffic flows from all users share the same queue at the bottleneck. Fur thermore, where traffic flows from all users share the same queue at the bottleneck. Fur thermore,
user mobility patterns in a cellular network differ from those in a Wi-Fi netw ork. user mobility patterns in a cellular network differ from those in a Wi-Fi netw ork.
Therefore, it is important to evaluate the performance of proposed candidate R TP-based Therefore, it is important to evaluate the performance of proposed candidate R TP-based
congestion control solutions over cellular mobile networks and over Wi-Fi netw orks congestion control solutions over cellular mobile networks and over Wi-Fi netw orks
respectively.</t> respectively.</t>
<t><xref target="RFC8868" format="default"/> provides guidelines
<t>The draft <xref target="I-D.ietf-rmcat-eval-criteria"></xref> provides the
guideline
for evaluating candidate algorithms and recognizes the importance of testing o ver wireless for evaluating candidate algorithms and recognizes the importance of testing o ver wireless
access networks. However, it does not describe any specific test cases for per formance access networks. However, it does not describe any specific test cases for per formance
evaluation of candidate algorithms. This document describes test cases specifi cally evaluation of candidate algorithms. This document describes test cases specifi cally
targeting cellular and Wi-Fi networks.</t> targeting cellular and Wi-Fi networks.</t>
</section> </section>
<section numbered="true" toc="default">
<section title="Cellular Network Specific Test Cases"> <name>Cellular Network Specific Test Cases</name>
<t>A cellular environment is more complicated than its wireline counterpar
<t>A cellular environment is more complicated than its wireline counterpart t
since it seeks to provide services in the context of variable available since it seeks to provide services in the context of variable available
bandwidth, location dependencies and user mobilities at different speeds. bandwidth, location dependencies, and user mobilities at different speeds.
In a cellular network, the user may reach the cell edge which may lead to In a cellular network, the user may reach the cell edge, which may lead to
a significant amount of retransmissions to deliver the data from the base a significant number of retransmissions to deliver the data from the base
station to the destination and vice versa. These radio links will often act station to the destination and vice versa. These radio links will often act
as a bottleneck for the rest of the network and will eventually lead to as a bottleneck for the rest of the network and will eventually lead to
excessive delays or packet drops. An efficient retransmission or link adapta tion excessive delays or packet drops. An efficient retransmission or link adapta tion
mechanism can reduce the packet loss probability but there will remain some mechanism can reduce the packet loss probability, but some
packet losses and delay variations. Moreover, with increased cell load or packet losses and delay variations will remain. Moreover, with increased cel
l load or
handover to a congested cell, congestion in the transport network will becom e handover to a congested cell, congestion in the transport network will becom e
even worse. Besides, there exist certain characteristics that distinguish th e even worse. Besides, there exist certain characteristics that distinguish th e
cellular network from other wireless access networks such as Wi-Fi. In a cellular network from other wireless access networks such as Wi-Fi. In a
cellular network -- </t> cellular network: </t>
<ul spacing="normal">
<t><list style="symbols"> <li>
<t>The bottleneck is often a shared link with relatively few users. <t>The bottleneck is often a shared link with relatively few users.
<list style="symbols"> </t>
<t>The cost per bit over the shared link varies over time and is differe <ul spacing="normal">
nt <li>The cost per bit over the shared link varies over time and is di
for different users.</t> fferent
<t>Leftover/unused resources can be consumed by other greedy users.</t> for different users.</li>
</list> <li>Leftover/unused resources can be consumed by other greedy users.
</t> </li>
</ul>
<t>Queues are always per radio bearer hence each user can have many such q </li>
ueues.</t> <li>Queues are always per radio bearer, hence each user can have many su
ch queues.</li>
<t>Users can experience both Inter and Intra Radio Access Technology (RAT) <li>Users can experience both inter- and intra-Radio Access Technology (
handovers RAT) handovers
(see <xref target="HO-def-3GPP"></xref> for the definition of "handover" (see <xref target="HO-def-3GPP" format="default"/> for the definition of
).</t> "handover").</li>
<li>Handover between cells or change of serving cells (as described in
<t>Handover between cells or change of serving cells (as described in <xref target="HO-LTE-3GPP" format="default"/> and <xref target="HO-UMTS-
<xref target="HO-LTE-3GPP"></xref> and <xref target="HO-UMTS-3GPP"></xre 3GPP" format="default"/>)
f>) might cause user plane interruptions, which can lead to bursts of packet
might cause user plane interruptions which can lead to bursts of packet losses,
losses, delay, and/or jitter. The exact behavior depends on the type of radio be
delay and/or jitter. The exact behavior depends on the type of radio bea arer.
rer.
Typically, the default best-effort bearers do not generate packet loss, instead, Typically, the default best-effort bearers do not generate packet loss, instead,
packets are queued up and transmitted once the handover is completed.</t packets are queued up and transmitted once the handover is completed.</l
> i>
<li>The network part decides how much the user can transmit.</li>
<t>The network part decides how much the user can transmit.</t> <li>
<t>The cellular network has variable link capacity per user.
<t>The cellular network has variable link capacity per user. </t>
<list style="symbols"> <ul spacing="normal">
<t>It can vary as fast as a period of milliseconds.</t> <li>It can vary as fast as a period of milliseconds.</li>
<li>It depends on many factors (such as distance, speed, interferenc
<t>It depends on many factors (such as distance, speed, interference, di e, different flows).</li>
fferent flows).</t> <li>It uses complex and smart link adaptation, which makes the link
behavior ever
<t>It uses complex and smart link adaptation which makes the link behavi more dynamic.</li>
or ever <li>The scheduling priority depends on the estimated throughput.</li
more dynamic.</t> >
</ul>
<t>The scheduling priority depends on the estimated throughput.</t> </li>
</list> <li>Both Quality of Service (QoS) and non-QoS radio bearers can be used.
</t> </li>
</ul>
<t>Both Quality of Service (QoS) and non-QoS radio bearers can be used.</t <t>Hence, a real-time communication application operating over a cellular
> network needs
</list></t> to cope with a shared bottleneck link and variable link capacity, events lik
e handover,
<t>Hence, a real-time communication application operating over a cellular non-congestion-related loss, and abrupt changes in bandwidth (both short ter
network needs m and long term)
to cope with a shared bottleneck link and variable link capacity, events lik due to handover, network load, and bad radio coverage. Even though 3GPP has
e handover, non-congestion related loss, abrupt changes in bandwidth (both short defined QoS
term and long term) bearers <xref target="QoS-3GPP" format="default"/> to ensure high-quality us
due to handover, network load and bad radio coverage. Even though 3GPP has d er experience, it is
efined QoS
bearers <xref target="QoS-3GPP"></xref> to ensure high-quality user experien
ce, it is
still preferable for real-time applications to behave in an adaptive manner. still preferable for real-time applications to behave in an adaptive manner.
</t> </t>
<t>Different mobile operators deploy their own cellular networks with thei
<t>Different mobile operators deploy their own cellular networks with their ow r own set of
n set of
network functionalities and policies. Usually, a mobile operator network inc ludes a network functionalities and policies. Usually, a mobile operator network inc ludes a
range of radio access technologies such as 3G and 4G/LTE. Looking at the spe cifications range of radio access technologies such as 3G and 4G/LTE. Looking at the spe cifications
of such radio technologies it is evident that only the more recent radio tec hnologies of such radio technologies, it is evident that only the more recent radio te chnologies
can support the high bandwidth requirements from real-time interactive video applications. can support the high bandwidth requirements from real-time interactive video applications.
The future real-time interactive application will impose even greater demand Future real-time interactive applications will impose even greater demand on
on cellular cellular
network performance which makes 4G (and beyond) radio technologies more suit network performance, which makes 4G (and beyond) radio technologies more sui
able for table for
such genre of application. such genre of application.
</t> </t>
<t>The key factors in defining test cases for cellular networks are: </t>
<t>The key factors in defining test cases for cellular networks are: </t> <ul spacing="normal">
<li>Shared and varying link capacity</li>
<t><list style="symbols"> <li>Mobility</li>
<t>Shared and varying link capacity</t> <li>Handover</li>
<t>Mobility</t> </ul>
<t>Handover</t> <t>However, these factors are typically highly correlated in a cellular ne
</list></t> twork.
<t>However, these factors are typically highly correlated in a cellular networ
k.
Therefore, instead of devising separate test cases for individual important ev ents, Therefore, instead of devising separate test cases for individual important ev ents,
we have divided the test case into two categories. It should be noted that the goal we have divided the test cases into two categories. It should be noted that th e goal
of the following test cases is to evaluate the performance of candidate algori thms of the following test cases is to evaluate the performance of candidate algori thms
over the radio interface of the cellular network. Hence it is assumed that the radio over the radio interface of the cellular network. Hence, it is assumed that th e radio
interface is the bottleneck link between the communicating peers and that the core interface is the bottleneck link between the communicating peers and that the core
network does not introduce any extra congestion along the path. Consequently, network does not introduce any extra congestion along the path. Consequently,
this draft this document
has kept as out of scope the combination of multiple access technologies invol has left out of scope the combination of multiple access technologies involvin
ving g
both cellular and Wi-Fi users. In this latter case the shared bottleneck is li both cellular and Wi-Fi users. In this latter case, the shared bottleneck is l
kely ikely
at the wired backhaul link. These test cases further assume a typical real-tim e at the wired backhaul link. These test cases further assume a typical real-tim e
telephony scenario where one real-time session consists of one voice stream an d one telephony scenario where one real-time session consists of one voice stream an d one
video stream. </t> video stream. </t>
<t> Even though it is possible to carry out tests over operational cellula
<t> Even though it is possible to carry out tests over operational cellul r
ar
networks (e.g., LTE/5G), and actually such tests are already available to day, networks (e.g., LTE/5G), and actually such tests are already available to day,
these tests cannot in general be carried out in a deterministic fashion to these tests cannot in general be carried out in a deterministic fashion to
ensure repeatability. The main reason is that these networks are controlled by ensure repeatability. The main reason is that these networks are controlled by
cellular operators and there exist various amounts of competing traffic in the cellular operators, and there exists various amounts of competing traffic in t he
same cell(s). In practice, it is only in underground mines that one can carry same cell(s). In practice, it is only in underground mines that one can carry
out near deterministic testing. Even there, it is not guaranteed either as wor kers out near deterministic testing. Even there, it is not guaranteed either as wor kers
in the mines may carry with them their personal mobile phones. Furthermore, th e in the mines may carry with them their personal mobile phones. Furthermore, th e
underground mining setting may not reflect typical usage patterns in an urban underground mining setting may not reflect typical usage patterns in an urban
setting. We, therefore, recommend that a cellular network simulator is used setting. We, therefore, recommend that a cellular network simulator be used
for the test cases defined in this document, for example -- the LTE simulator for the test cases defined in this document, for example -- the LTE simulator
in <xref target="NS-3"></xref>. </t> in <xref target="NS-3" format="default"/>. </t>
<section anchor="VNL" numbered="true" toc="default">
<section anchor="VNL" title="Varying Network Load"> <name>Varying Network Load</name>
<t>The goal of this test is to evaluate the performance of the candidate
<t>The goal of this test is to evaluate the performance of the candidate conge congestion
stion
control algorithm under varying network load. The network load variation is created control algorithm under varying network load. The network load variation is created
by adding and removing network users a.k.a. User Equipments (UEs) during the simulation. by adding and removing network users, a.k.a. User Equipment (UE), during the simulation.
In this test case, each user/UE in the media session is an endpoint followin g RTP-based In this test case, each user/UE in the media session is an endpoint followin g RTP-based
congestion control. User arrivals follow a Poisson distribution proportional to the congestion control. User arrivals follow a Poisson distribution proportional to the
length of the call, to keep the number of users per cell fairly constant dur ing the length of the call, to keep the number of users per cell fairly constant dur ing the
evaluation period. At the beginning of the simulation, there should be enoug h time to evaluation period. At the beginning of the simulation, there should be enoug h time to
warm-up the network. This is to avoid running the evaluation in an empty net warm up the network. This is to avoid running the evaluation in an empty net
work where work where
network nodes are having empty buffers, low interference at the beginning of network nodes have empty buffers and low interference at the beginning of th
the simulation. e simulation.
This network initialization period should be excluded from the evaluation pe This network initialization period should be excluded from the evaluation pe
riod. Typically, the evaluation period starts 30 seconds after test initializati riod.
on. </t> Typically, the evaluation period starts 30 seconds after test initialization
. </t>
<t>This test case also includes user mobility and some competing traffic. <t>This test case also includes user mobility and some competing traffic
The latter . The latter
includes both the same types of flows (with same adaptation algorithms) and different includes both the same types of flows (with same adaptation algorithms) and different
types of flows (with different services and congestion control schemes). </t > types of flows (with different services and congestion control schemes). </t >
<!-- <section anchor="NC-VNL" numbered="true" toc="default">
The investigated <name>Network Connection</name>
congestion control algorithms should show maximum possible network utilizati <t>Each mobile user is connected to a fixed user. The connection betwe
on and en the mobile user
stability in terms of rate variations, lowest possible end to end frame late and fixed user consists of a cellular radio access, an Evolved Packet Core (
ncy, EPC), and
network latency and Packet Loss Rate (PLR) at different cell load level.</t>
-->
<section anchor="NC-VNL" title="Network Connection">
<t>Each mobile user is connected to a fixed user. The connection between the m
obile user
and fixed user consists of a cellular radio access, an Evolved Packet Core (
EPC) and
an Internet connection. The mobile user is connected to the EPC using cellul ar radio an Internet connection. The mobile user is connected to the EPC using cellul ar radio
access technology which is further connected to the Internet. At the other e access technology, which is further connected to the Internet. At the other
nd, the end, the
fixed user is connected to the Internet via wired connection with sufficient fixed user is connected to the Internet via a wired connection with sufficie
ly high ntly high
bandwidth, for instance, 10 Gbps, so that the system bottleneck is on the ce llular bandwidth, for instance, 10 Gbps, so that the system bottleneck is on the ce llular
radio access interface. The wired connection to in this setup does not intro duce any radio access interface. The wired connection in this setup does not introduc e any
network impairments to the test; it only adds 10 ms of one-way propagation d elay. network impairments to the test; it only adds 10 ms of one-way propagation d elay.
</t> </t>
<t>The path from the fixed user to the mobile users is defined as "dow
<t>The path from the fixed user to the mobile users is defined as "Downlink" a nlink", and the
nd the path from the mobile users to the fixed user is defined as "uplink". We assu
path from the mobile users to the fixed user is defined as "Uplink". We assu me that
me that
only uplink or downlink is congested for mobile users. Hence, we recommend t hat the only uplink or downlink is congested for mobile users. Hence, we recommend t hat the
uplink and downlink simulations are run separately. uplink and downlink simulations are run separately.
</t> </t>
<figure anchor="fig-siml-topology">
<t> <name>Simulation Topology</name>
<artwork align="center" name="Simulation Topology" type="" alt=""><!
<figure align="center" anchor="fig-siml-topology" title="Simulation Topology [CDATA[
">
<artwork align="center" name="Simulation Topology"><![CDATA[
uplink uplink
++))) +--------------------------> ++))) +-------------------------->
++-+ ((o)) ++-+ ((o))
| | / \ +-------+ +------+ +---+ | | / \ +-------+ +------+ +---+
+--+ / \----+ +-----+ +----+ | +--+ / \----+ +-----+ +----+ |
/ \ +-------+ +------+ +---+ / \ +-------+ +------+ +---+
UE BS EPC Internet fixed UE BS EPC Internet fixed
<--------------------------+ <--------------------------+
downlink downlink
]]></artwork> ]]></artwork>
</figure></t> </figure>
</section>
</section> <section anchor="SS-VNL" numbered="true" toc="default">
<name>Simulation Setup</name>
<section anchor="SS-VNL" title="Simulation Setup"> <t>The values enclosed within "[ ]" for the following simulation attri
butes
<t>The values enclosed within "[ ]" for the following simulation attribut follow the same notion as in <xref target="RFC8867" format="default"/>.
es The desired simulation setup is as follows: </t>
follow the same notion as in <xref target="I-D.ietf-rmcat-eval-test"></xr <dl newline="false" spacing="normal">
ef>. <dt>Radio environment:</dt>
The desired simulation setup is as follows -- </t> <dd>
<t><br/></t>
<t><list style="numbers"> <dl newline="false" spacing="normal">
<t>Radio environment: <dt>Deployment and propagation model:</dt> <dd>3GPP case 1 (see <xref targ
<list style="letters"> et="HO-deploy-3GPP" format="default"/>)</dd>
<t>Deployment and propagation model: 3GPP case 1 <dt>Antenna:</dt> <dd> Multiple-Input and Multiple-Output (MIMO), 2D or 3D
(see <xref target="HO-deploy-3GPP"></xref>)</t> antenna pattern</dd>
<dt>Mobility:</dt> <dd> [3 km/h, 30 km/h]</dd>
<t>Antenna: Multiple-Input and Multiple-Output (MIMO), 2D or 3D antenna patt <dt>Transmission bandwidth:</dt> <dd> 10 MHz</dd>
ern.</t> <dt>Number of cells:</dt> <dd> multi-cell deployment (3 cells per Base Sta
tion (BS) * 7 BS) = 21 cells</dd>
<t>Mobility: [3km/h, 30km/h]</t> <dt>Cell radius:</dt> <dd> 166.666 meters</dd>
<dt>Scheduler:</dt> <dd> Proportional fair with no priority</dd>
<t>Transmission bandwidth: 10MHz</t> <dt>Bearer:</dt> <dd> Default bearer for all traffic</dd>
<dt>Active Queue Management (AQM) settings: </dt> <dd>AQM [on, off]</dd>
<t>Number of cells: multi-cell deployment </dl>
(3 Cells per Base Station (BS) * 7 BS) = 21 cells</t> </dd>
<dt>End-to-end Round Trip Time (RTT): </dt> <dd>[40 ms, 150 ms]</dd>
<t>Cell radius: 166.666 Meters</t> <dt>User arrival model: </dt> <dd>Poisson arrival model</dd>
<dt>User intensity:</dt>
<t>Scheduler: Proportional fair with no priority</t> <dd>
<t><br/></t>
<t>Bearer: Default bearer for all traffic.</t> <dl newline="false" spacing="normal">
<t>Active Queue Management (AQM) settings: AQM [on,off]</t>
</list></t>
<t>End-to-end Round Trip Time (RTT): [40ms, 150ms]</t>
<t>User arrival model: Poisson arrival model</t>
<t>User intensity:
<list style="symbols">
<!-- [TODO] please explain/define what user intensity is, with what unit -
->
<t>Downlink user intensity: {0.7, 1.4, 2.1, 2.8, 3.5, 4.2,
4.9, 5.6, 6.3, 7.0, 7.7, 8.4, 9,1, 9.8, 10.5}</t>
<t>Uplink user intensity : {0.7, 1.4, 2.1, 2.8, 3.5, 4.2,
4.9, 5.6, 6.3, 7.0}</t>
</list>
</t>
<t>Simulation duration: 91s</t>
<t>Evaluation period: 30s-60s</t>
<t>Media traffic:
<list counter="reqs" style="numbers">
<t>Media type: Video<list style="letters">
<t>Media direction: [Uplink, Downlink]</t>
<t>Number of Media source per user: One (1)</t>
<t>Media duration per user: 30s</t>
<t>Media source: same as defined in Section 4.3 of
<xref target="I-D.ietf-rmcat-eval-test"></xref></t>
</list>
</t>
<t>Media Type: Audio
<list style="letters">
<t>Media direction: Uplink and Downlink</t>
<t>Number of Media source per user: One (1)</t>
<t>Media duration per user: 30s</t>
<t>Media codec: Constant Bit Rate (CBR)</t>
<t>Media bitrate: 20 Kbps</t>
<t>Adaptation: off</t>
</list>
</t>
</list></t>
<t>Other traffic models:
<list style="symbols">
<t>Downlink simulation: Maximum of 4Mbps/cell (web browsing
or FTP traffic following default TCP congestion control
<xref target="RFC5681"/>)</t>
<t>Unlink simulation: Maximum of 2Mbps/cell (web browsing
or FTP traffic following default TCP congestion control
<xref target="RFC5681"/>)</t>
</list>
</t>
</list></t>
</section> <dt>Downlink user intensity:</dt> <dd> {0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9,
5.6, 6.3, 7.0, 7.7, 8.4, 9,1, 9.8, 10.5}</dd>
<dt>Uplink user intensity:</dt> <dd> {0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9, 5
.6, 6.3, 7.0}</dd>
</dl>
</dd>
<dt>Simulation duration:</dt> <dd> 91 s</dd>
<dt>Evaluation period:</dt> <dd> 30 s - 60 s</dd>
<dt>Media traffic:</dt>
<dd>
<t><br/></t>
<dl newline="false" spacing="normal">
<dt>Media type:</dt>
<dd>
<t>Video</t>
<dl newline="false" spacing="normal">
<dt>Media direction:</dt> <dd> [uplink, downlink]</dd>
<dt>Number of media sources per user:</dt> <dd> One (1)</dd>
<dt>Media duration per user:</dt> <dd> 30 s</dd>
<dt>Media source:</dt> <dd>same as defined in <xref target="RFC8867" s
ection="4.3" sectionFormat="of" format="default"/></dd>
</dl>
</dd>
<dt>Media type:</dt>
<dd>
<t>Audio</t>
<dl newline="false" spacing="normal">
<dt>Media direction:</dt> <dd> [uplink, downlink]</dd>
<dt>Number of media sources per user:</dt> <dd> One (1)</dd>
<dt>Media duration per user:</dt> <dd> 30 s</dd>
<dt>Media codec:</dt> <dd> Constant Bit Rate (CBR)</dd>
<dt>Media bitrate:</dt> <dd> 20 Kbps</dd>
<dt>Adaptation:</dt> <dd> off</dd>
</dl>
</dd>
</dl>
</dd>
<dt>Other traffic models: </dt>
<dd>
<t><br/></t>
<dl newline="false" spacing="normal">
<dt>Downlink simulation: </dt> <dd>Maximum of 4 Mbps/cell (web browsing or
FTP traffic following default TCP congestion control
<xref target="RFC5681" format="default"/>)</dd>
<dt>Uplink simulation: </dt> <dd>Maximum of 2 Mbps/cell (web browsing or F
TP traffic following default TCP congestion control
<xref target="RFC5681" format="default"/>)</dd>
</dl>
</dd>
</dl>
<section title="Expected behavior"> </section>
<t> <section numbered="true" toc="default">
<name>Expected Behavior</name>
<t>
The investigated congestion control algorithms should result in maximum The investigated congestion control algorithms should result in maximum
possible network utilization and stability in terms of rate variations, possible network utilization and stability in terms of rate variations,
lowest possible end to end frame latency, network latency and Packet Loss lowest possible end-to-end frame latency, network latency, and Packet Loss
Rate (PLR) at different cell load levels.</t> Rate (PLR) at different cell load levels.</t>
</section> </section>
</section>
</section> <section numbered="true" toc="default">
<name>Bad Radio Coverage</name>
<section title="Bad Radio Coverage"> <t>The goal of this test is to evaluate the performance of the candidate
<t>The goal of this test is to evaluate the performance of candidate
congestion control algorithm when users visit part of the network with congestion control algorithm when users visit part of the network with
bad radio coverage. The scenario is created by using a larger cell bad radio coverage. The scenario is created by using a larger cell
radius than that in the previous test case. In this test case, each radius than that in the previous test case. In this test case, each
user/UE in the media session is an endpoint following RTP-based user/UE in the media session is an endpoint following RTP-based
congestion control. User arrivals follow a Poisson distribution proportional congestion control. User arrivals follow a Poisson distribution proportional
to the length of the call, to keep the number of users per cell fairly to the length of the call, to keep the number of users per cell fairly
constant during the evaluation period. At the beginning of the simulation, constant during the evaluation period. At the beginning of the simulation,
there should be enough amount of time to warm-up the network. This is to there should be enough time to warm up the network. This is to
avoid running the evaluation in an empty network where network nodes are avoid running the evaluation in an empty network where network nodes
having empty buffers, low interference at the beginning of the simulation. have empty buffers and low interference at the beginning of the simulation.
This network initialization period should be excluded from the evaluation This network initialization period should be excluded from the evaluation
period. Typically, the evaluation period starts 30 seconds after test initia lization. </t> period. Typically, the evaluation period starts 30 seconds after test initia lization. </t>
<t>This test case also includes user mobility and some competing traffic
<t>This test case also includes user mobility and some competing traffic. .
The latter includes the same kind of flows (with same adaptation algorithms) .</t> The latter includes the same kind of flows (with same adaptation algorithms) .</t>
<!-- <section numbered="true" toc="default">
The investigated congestion control algorithms should result in maximum <name>Network Connection</name>
possible network utilization and stability in terms of rate variations, <t>Same as defined in <xref target="NC-VNL" format="default"/>.</t>
lowest possible end to end frame latency, network latency and Packet Loss </section>
Rate (PLR) at different cell load levels.</t> <section numbered="true" toc="default">
--> <name>Simulation Setup</name>
<t>The desired simulation setup is the same as the Varying Network Loa
<section title="Network connection"> d
test case defined in <xref target="VNL" format="default"/> except for the
<t>Same as defined in <xref target="NC-VNL"></xref></t> following
changes:</t>
</section>
<section title="Simulation Setup">
<t>The desired simulation setup is the same as the Varying Network Load
test case defined in <xref target="VNL"></xref> except the following
changes:
<list style="numbers">
<t>Radio environment: Same as defined in <xref target="SS-VNL"></xref>
except the following:
<list style="letters">
<t>Deployment and propagation model: 3GPP case 3
(see <xref target="HO-deploy-3GPP"></xref>)</t>
<t>Cell radius: 577.3333 Meters</t>
<t>Mobility: 3km/h</t>
</list></t>
<t>User intensity = {0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9, 5.6, 6.3, 7.0}</t>
<t>Media traffic model: Same as defined in <xref target="SS-VNL"></xref></
t>
<t>Other traffic models:
<list style="symbols">
<t>Downlink simulation: Maximum of 2Mbps/cell (web browsing
or FTP traffic following default TCP congestion control
<xref target="RFC5681"/>)</t>
<t>Unlink simulation: Maximum of 1Mbps/cell (web browsing
or FTP traffic following default TCP congestion control
<xref target="RFC5681"/>)</t>
</list></t>
</list></t>
</section>
<section title="Expected behavior"> <dl spacing="normal">
<dt>Radio environment:</dt>
<dd>
<t>Same as defined in <xref target="SS-VNL" format="default"/>
except for the following:</t>
<dl spacing="normal">
<dt>Deployment and propagation model:</dt>
<dd>3GPP case 3 (see <xref target="HO-deploy-3GPP" format=
"default"/>)</dd>
<dt>Cell radius:</dt>
<dd>577.3333 meters</dd>
<dt>Mobility:</dt>
<dd>3 km/h</dd>
</dl>
</dd>
<dt>User intensity:</dt>
<dd>{0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9, 5.6, 6.3, 7.0}</dd>
<dt>Media traffic model:</dt>
<dd>Same as defined in <xref target="SS-VNL" format="default"/></dd
>
<dt>Other traffic models:</dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Downlink simulation:</dt>
<dd>Maximum of 2 Mbps/cell (web browsing or FTP traffic fol
lowing default TCP congestion control <xref target="RFC5681" format="default"/>)
</dd>
<dt>Uplink simulation:</dt>
<dd>Maximum of 1 Mbps/cell (web browsing or FTP traffic fol
lowing default TCP congestion control <xref target="RFC5681" format="default"/>)
</dd>
</dl>
</dd>
</dl>
<t>The investigated congestion control algorithms should result in maximum </section>
<section numbered="true" toc="default">
<name>Expected Behavior</name>
<t>The investigated congestion control algorithms should result in max
imum
possible network utilization and stability in terms of rate variations, possible network utilization and stability in terms of rate variations,
lowest possible end to end frame latency, network latency and Packet Loss lowest possible end-to-end frame latency, network latency, and Packet Loss
Rate (PLR) at different cell load levels.</t> Rate (PLR) at different cell load levels.</t>
</section>
</section> </section>
<section numbered="true" toc="default">
</section> <name>Desired Evaluation Metrics for Cellular Test Cases</name>
<t>The evaluation criteria document <xref target="RFC8868" format="defau
<section title="Desired Evaluation Metrics for cellular test cases"> lt"/>
<t>The evaluation criteria document <xref target="I-D.ietf-rmcat-eval-criteria
"></xref>
defines the metrics to be used to evaluate candidate algorithms. Considering defines the metrics to be used to evaluate candidate algorithms. Considering
the nature and distinction of cellular networks we recommend that at least the the nature and distinction of cellular networks, we recommend that at least th e
following metrics be used to evaluate the performance of the candidate al gorithms: </t> following metrics be used to evaluate the performance of the candidate al gorithms: </t>
<ul spacing="normal">
<t> <li>Average cell throughput (for all cells), shows cell utilization.</
<list style="symbols"> li>
<t>Average cell throughput (for all cells), shows cell utilizations.</t> <li>Application sending and receiving bitrate, goodput.</li>
<li>Packet Loss Rate (PLR).</li>
<t>Application sending and receiving bitrate, goodput.</t> <li>End-to-end media frame delay. For video, this means the delay from
capture to display.</li>
<t>Packet Loss Rate (PLR).</t> <li>Transport delay.</li>
<li>Algorithm stability in terms of rate variation.</li>
<t>End-to-end Media frame delay. For video, this means the delay from captur </ul>
e to display.</t> </section>
</section>
<t>Transport delay.</t> <section numbered="true" toc="default">
<name>Wi-Fi Networks Specific Test Cases</name>
<t>Algorithm stability in terms of rate variation.</t> <t>Given the prevalence of Internet access links over Wi-Fi, it is importa
</list></t> nt to
</section>
</section>
<section title="Wi-Fi Networks Specific Test Cases">
<t>Given the prevalence of Internet access links over Wi-Fi, it is important to
evaluate candidate RTP-based congestion control solutions over test cases that evaluate candidate RTP-based congestion control solutions over test cases that
include Wi-Fi access links. Such evaluations should highlight the inherently include Wi-Fi access links. Such evaluations should highlight the inherently
different characteristics of Wi-Fi networks in contrast to their wired counter parts:</t> different characteristics of Wi-Fi networks in contrast to their wired counter parts:</t>
<ul spacing="normal">
<t><list style="symbols"> <li>The wireless radio channel is subject to interference from nearby tr
<t>The wireless radio channel is subject to interference from nearby transmitt ansmitters,
ers,
multipath fading, and shadowing. These effects lead to fluctuations in the l ink multipath fading, and shadowing. These effects lead to fluctuations in the l ink
throughput and sometimes an error-prone communication environment.</t> throughput and sometimes an error-prone communication environment.</li>
<li>Available network bandwidth is not only shared over the air between
<t>Available network bandwidth is not only shared over the air between concurr concurrent
ent
users but also between uplink and downlink traffic due to the half-duplex na ture users but also between uplink and downlink traffic due to the half-duplex na ture
of the wireless transmission medium.</t> of the wireless transmission medium.</li>
<li>Packet transmissions over Wi-Fi are susceptible to contentions and c
<t>Packet transmissions over Wi-Fi are susceptible to contentions and collisio ollisions
ns
over the air. Consequently, traffic load beyond a certain utilization level over over the air. Consequently, traffic load beyond a certain utilization level over
a Wi-Fi network can introduce frequent collisions over the air and significa nt a Wi-Fi network can introduce frequent collisions over the air and significa nt
network overhead, as well as packet drops due to buffer overflow at the tran smitters. network overhead, as well as packet drops due to buffer overflow at the tran smitters.
This, in turn, leads to excessive delay, retransmissions, packet losses and lower This, in turn, leads to excessive delay, retransmissions, packet losses, and lower
effective bandwidth for applications. Note further that the collision-induce d delay effective bandwidth for applications. Note further that the collision-induce d delay
and loss patterns are qualitatively different from those caused by congestio n over and loss patterns are qualitatively different from those caused by congestio n over
a wired connection. </t> a wired connection. </li>
<li>The IEEE 802.11 standard (i.e., Wi-Fi) supports multi-rate transmiss
<t>The IEEE 802.11 standard (i.e., Wi-Fi) supports multi-rate transmission cap ion capabilities
abilities
by dynamically choosing the most appropriate modulation and coding scheme (M CS) for by dynamically choosing the most appropriate modulation and coding scheme (M CS) for
the given received signal strength. A different choice in the MCS Index lead s to the given received signal strength. A different choice in the MCS Index lead s to
different physical-layer (PHY-layer) link rates and consequently different different physical-layer (PHY-layer) link rates and consequently different
application-layer throughput.</t> application-layer throughput.</li>
<li>The presence of legacy devices (e.g., ones operating only in IEEE 80
<t>The presence of legacy devices (e.g., ones operating only in IEEE 802.11b) 2.11b) at a much
at a much
lower PHY-layer link rate can significantly slow down the rest of a modern W i-Fi lower PHY-layer link rate can significantly slow down the rest of a modern W i-Fi
network. As discussed in <xref target="Heusse2003"></xref>, the main reason for network. As discussed in <xref target="Heusse2003" format="default"/>, the m ain reason for
such anomaly is that it takes much longer to transmit the same packet over a slower such anomaly is that it takes much longer to transmit the same packet over a slower
link than over a faster link, thereby consuming a substantial portion of air link than over a faster link, thereby consuming a substantial portion of air
time.</t> time.</li>
<li>Handover from one Wi-Fi Access Point (AP) to another may lead to exc
<t>Handover from one Wi-Fi Access Point (AP) to another may lead to excessive essive packet
packet delays and losses during the process.</li>
delays and losses during the process.</t> <li>IEEE 802.11e has introduced the Enhanced Distributed Channel Access
(EDCA)
<t>IEEE 802.11e has introduced the Enhanced Distributed Channel Access (EDCA)
mechanism to allow different traffic categories to contend for channel acces s mechanism to allow different traffic categories to contend for channel acces s
using different random back-off parameters. This mechanism is a mandatory re quirement using different random back-off parameters. This mechanism is a mandatory re quirement
for the Wi-Fi Multimedia (WMM) certification in Wi-Fi Alliance. It allows fo r for the Wi-Fi Multimedia (WMM) certification in Wi-Fi Alliance. It allows fo r
prioritization of real-time application traffic such as voice and video over prioritization of real-time application traffic such as voice and video over
non-urgent data transmissions (e.g., file transfer).</t> non-urgent data transmissions (e.g., file transfer).</li>
</list></t> </ul>
<t>In summary, the presence of Wi-Fi access links in different network top
<t>In summary, the presence of Wi-Fi access links in different network topolog ologies
ies can exert different impacts on the network performance in terms of applicati
can exert different impact on the network performance in terms of applicatio on-layer
n-layer
effective throughput, packet loss rate, and packet delivery delay. These, in turn, effective throughput, packet loss rate, and packet delivery delay. These, in turn,
will influence the behavior of end-to-end real-time multimedia congestion co ntrol.</t> will influence the behavior of end-to-end real-time multimedia congestion co ntrol.</t>
<t>Unless otherwise mentioned, the test cases in this section choose the P
<t>Unless otherwise mentioned, the test cases in this section choose the PHY- HY- and
and MAC-layer parameters based on the IEEE 802.11n standard. Statistics collecte
MAC-layer parameters based on the IEEE 802.11n Standard. Statistics collecte d from
d from
enterprise Wi-Fi networks show that the two dominant physical modes are 802. 11n enterprise Wi-Fi networks show that the two dominant physical modes are 802. 11n
and 802.11ac, accounting for 41% and 58% of connected devices. As Wi-Fi stan dards and 802.11ac, accounting for 41% and 58% of connected devices, respectively. As Wi-Fi standards
evolve over time -- for instance, with the introduction of the emerging Wi-F i 6 evolve over time -- for instance, with the introduction of the emerging Wi-F i 6
(based on IEEE 802.11ax) products -- the PHY- and MAC-layer test case specif ications (based on IEEE 802.11ax) products -- the PHY- and MAC-layer test case specif ications
need to be updated accordingly to reflect such changes.</t> need to be updated accordingly to reflect such changes.</t>
<t>Typically, a Wi-Fi access network connects to a wired infrastructure. E
<t>Typically, a Wi-Fi access network connects to a wired infrastructure. Eithe ither
r
the wired or the Wi-Fi segment of the network can be the bottleneck. The fol lowing the wired or the Wi-Fi segment of the network can be the bottleneck. The fol lowing
sections describe basic test cases for both scenarios separately. The same s et of sections describe basic test cases for both scenarios separately. The same s et of
performance metrics as in <xref target="I-D.ietf-rmcat-eval-test"></xref>) s hould performance metrics as in <xref target="RFC8867" format="default"/>) should
be collected for each test case. </t> be collected for each test case. </t>
<t>We recommend carrying out the test cases as defined in this document us
<t>We recommend to carry out the test cases as defined in this document using ing a simulator,
a simulator, such as <xref target="NS-2" format="default"/> or <xref target="NS-3" format
such as <xref target="NS-2"></xref> or <xref target="NS-3"></xref>. When fea ="default"/>. When feasible, it
sible, it
is encouraged to perform testbed-based evaluations using Wi-Fi access points and is encouraged to perform testbed-based evaluations using Wi-Fi access points and
endpoints running up-to-date IEEE 802.11 protocols, such as 802.11ac and the emerging endpoints running up-to-date IEEE 802.11 protocols, such as 802.11ac and the emerging
Wi-Fi 6, so as to verify the viability of the candidate schemes.</t> Wi-Fi 6, so as to verify the viability of the candidate schemes.</t>
<section anchor="sec-wired-bottleneck" numbered="true" toc="default">
<section anchor="sec-wired-bottleneck" <name>Bottleneck in Wired Network</name>
title="Bottleneck in Wired Network"> <t>The test scenarios below are intended to mimic the setup of video con
ferencing
<t>The test scenarios below are intended to mimic the setup of video conferenc
ing
over Wi-Fi connections from the home. Typically, the Wi-Fi home network is n ot over Wi-Fi connections from the home. Typically, the Wi-Fi home network is n ot
congested and the bottleneck is present over the wired home access link. Alt hough congested, and the bottleneck is present over the wired home access link. Al though
it is expected that test evaluation results from this section are similar to those it is expected that test evaluation results from this section are similar to those
as in <xref target="I-D.ietf-rmcat-eval-test"></xref>, it is still worthwhil e to in <xref target="RFC8867" format="default"/>, it is still worthwhile to
run through these tests as sanity checks.</t> run through these tests as sanity checks.</t>
<section anchor="sec-wifi-wired-bottleneck-topo" numbered="true" toc="de
<section anchor="sec-wifi-wired-bottleneck-topo" fault">
title="Network topology"> <name>Network Topology</name>
<t><xref target="fig-wifi-test-topology" format="default"/> shows the
<t><xref target="fig-wifi-test-topology"></xref> shows the network topology network topology
of Wi-Fi test cases. The test contains multiple mobile nodes (MNs) connected of Wi-Fi test cases. The test contains multiple mobile nodes (MNs) connected
to a common Wi-Fi access point (AP) and their corresponding wired clients on to a common Wi-Fi AP and their corresponding wired clients on
fixed nodes (FNs). Each connection carries either a RTP-based media flow or fixed nodes (FNs). Each connection carries either an RTP-based media flow or
a TCP traffic flow. Directions of the flows can be uplink (i.e., from mobile a TCP traffic flow. Directions of the flows can be uplink (i.e., from mobile
nodes to fixed nodes), downlink (i.e., from fixed nodes to mobile nodes), or nodes to fixed nodes), downlink (i.e., from fixed nodes to mobile nodes), or
bi-directional. The total number of uplink/downlink/bi-directional flows for bidirectional. The total number of uplink/downlink/bidirectional flows for
RTP-based media traffic and TCP traffic are denoted as N and M, respectively.< /t> RTP-based media traffic and TCP traffic are denoted as N and M, respectively.< /t>
<figure anchor="fig-wifi-test-topology">
<t><figure align="center" <name>Network Topology for Wi-Fi Test Cases</name>
anchor="fig-wifi-test-topology" <artwork align="center" name="Network Topology for Wi-Fi Test Cases"
title="Network topology for Wi-Fi test cases"> type="" alt=""><![CDATA[
<artwork align="center"
name="Network topology for Wi-Fi test cases"><![CDATA[
Uplink Uplink
+----------------->+ +----------------->+
+------+ +------+ +------+ +------+
| MN_1 |)))) /=====| FN_1 | | MN_1 |)))) /=====| FN_1 |
+------+ )) // +------+ +------+ )) // +------+
. )) // . . )) // .
. )) // . . )) // .
. )) // . . )) // .
+------+ +----+ +-----+ +------+ +------+ +----+ +-----+ +------+
| MN_N | ))))))) | | | |========| FN_N | | MN_N | ))))))) | | | |========| FN_N |
skipping to change at line 688 skipping to change at line 529
| MN_tcp_1 | )))) | | | |======| FN_tcp_1 | | MN_tcp_1 | )))) | | | |======| FN_tcp_1 |
+----------+ +----+ +-----+ +----------+ +----------+ +----+ +-----+ +----------+
. )) \\ . . )) \\ .
. )) \\ . . )) \\ .
. )) \\ . . )) \\ .
+----------+ )) \\ +----------+ +----------+ )) \\ +----------+
| MN_tcp_M |))) \=====| FN_tcp_M | | MN_tcp_M |))) \=====| FN_tcp_M |
+----------+ +----------+ +----------+ +----------+
+<-----------------+ +<-----------------+
Downlink Downlink
]]></artwork> ]]></artwork>
</figure></t> </figure>
</section> </section>
<section numbered="true" toc="default">
<section title="Test/simulation setup"> <name>Test/Simulation Setup</name>
<t><list style="symbols">
<t>Test duration: 120s</t>
<t>Wi-Fi network characteristics:
<list style="symbols">
<t>Radio propagation model: Log-distance path loss propagation
model (see <xref target="NS3WiFi"></xref>)</t>
<t>PHY- and MAC-layer configuration: IEEE 802.11n</t>
<t>MCS Index at 11: 16-QAM 1/2, Raw Data Rate at 52Mbps</t>
</list></t>
<t>Wired path characteristics:
<list style="symbols">
<t>Path capacity: 1Mbps</t>
<t>One-Way propagation delay: 50ms.</t>
<t>Maximum end-to-end jitter: 30ms</t>
<t>Bottleneck queue type: Drop tail.</t>
<t>Bottleneck queue size: 300ms.</t>
<t>Path loss ratio: 0%.</t>
</list></t>
<t>Application characteristics:
<list style="symbols">
<t>Media Traffic:
<list style="symbols">
<t>Media type: Video</t>
<t>Media direction: See <xref target="subsec-4-1-3"></xref></t>
<t>Number of media sources (N): See <xref target="subsec-4-1-3"></xref
></t>
<t>Media timeline:
<list style="symbols">
<t>Start time: 0s.</t>
<t>End time: 119s.</t>
</list></t>
</list></t>
<t>Competing traffic:
<list style="symbols">
<t>Type of sources: long-lived TCP or CBR over UDP</t>
<t>Traffic direction: See <xref target="subsec-4-1-3"></xref></t>
<t>Number of sources (M): See <xref target="subsec-4-1-3"></xref></t
>
<t>Congestion control: Default TCP congestion control <xref target="
RFC5681"></xref>
or constant-bit-rate (CBR) traffic over UDP.</t>
<t>Traffic timeline: See <xref target="subsec-4-1-3"></xref></t>
</list></t>
</list></t>
</list></t>
</section>
<section anchor = "subsec-4-1-3" title="Typical test scenarios">
<t>
<list style="symbols">
<t>Single uplink RTP-based media flow: N=1 with uplink direction and M=0.<
/t>
<t>One pair of bi-directional RTP-based media flows: N=2 (i.e., one uplink <dl spacing="normal">
flow and one downlink flow); M=0.</t> <dt>Test duration:</dt><dd>120 s</dd>
<dt>Wi-Fi network characteristics: </dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Radio propagation model:</dt><dd>Log-distance path los
s propagation model (see <xref target="NS3WiFi" format="default"/>)</dd>
<dt>PHY- and MAC-layer configuration:</dt><dd>IEEE 802.11n
</dd>
<dt>MCS Index at 11:</dt><dd>Raw data rate at 52 Mbps,
16-QAM (Quadrature amplitude modulation) and 1/2 co
ding rate</dd>
</dl>
</dd>
<dt>Wired path characteristics: </dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Path capacity:</dt><dd>1 Mbps</dd>
<dt>One-way propagation delay:</dt><dd>50 ms</dd>
<dt>Maximum end-to-end jitter:</dt><dd>30 ms</dd>
<dt>Bottleneck queue type:</dt><dd>Drop tail</dd>
<dt>Bottleneck queue size:</dt><dd>300 ms</dd>
<dt>Path loss ratio:</dt><dd>0%</dd>
</dl>
</dd>
<dt>Application characteristics: </dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Media traffic: </dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Media type:</dt><dd>Video</dd>
<dt>Media direction:</dt><dd>See <xref target="subs
ec-4-1-3" format="default"/></dd>
<dt>Number of media sources (N):</dt><dd>See <xref
target="subsec-4-1-3" format="default"/></dd>
<dt>Media timeline:</dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Start time:</dt><dd>0 s</dd>
<dt>End time:</dt><dd>119 s</dd>
</dl>
</dd>
</dl>
</dd>
<dt>Competing traffic:</dt>
<dd>
<t><br/></t>
<dl spacing="normal">
<dt>Type of sources:</dt><dd>Long-lived TCP or CBR o
ver UDP</dd>
<dt>Traffic direction:</dt><dd>See <xref target="sub
sec-4-1-3" format="default"/></dd>
<dt>Number of sources (M):</dt><dd>See <xref target=
"subsec-4-1-3" format="default"/></dd>
<dt>Congestion control:</dt><dd>Default TCP congesti
on control <xref target="RFC5681" format="default"/> or CBR traffic over UDP</dd
>
<dt>Traffic timeline:</dt><dd>See <xref target="subs
ec-4-1-3" format="default"/></dd>
</dl>
</dd>
</dl>
</dd>
</dl>
<t>One pair of bi-directional RTP-based media flows: N=2; one uplink on-of </section>
f <section anchor="subsec-4-1-3" numbered="true" toc="default">
<name>Typical Test Scenarios</name>
<dl spacing="normal">
<dt>Single uplink RTP-based media flow:</dt><dd>N=1 with uplink di
rection and M=0.</dd>
<dt>One pair of bidirectional RTP-based media flows: </dt><dd>N=2
(i.e., one uplink
flow and one downlink flow); M=0.</dd>
<dt>One pair of bidirectional RTP-based media flows:</dt><dd>N=2; one uplink
on-off
CBR flow over UDP: M=1 (uplink). The CBR flow has ON time at t=0s-60s an d CBR flow over UDP: M=1 (uplink). The CBR flow has ON time at t=0s-60s an d
OFF time at t=60s-119s.</t> OFF time at t=60s-119s.</dd>
<dt>One pair of bidirectional RTP-based media flows:</dt><dd>N=2; one uplink
<t>One pair of bi-directional RTP-based media flows: N=2; one uplink off-o off-on
n
CBR flow over UDP: M=1 (uplink). The CBR flow has OFF time at t=0s-60s a nd CBR flow over UDP: M=1 (uplink). The CBR flow has OFF time at t=0s-60s a nd
ON time at t=60s-119s.</t> ON time at t=60s-119s.</dd>
<dt>One RTP-based media flow competing against one long-lived TCP fl
<t>One RTP-based media flow competing against one long-live TCP flow in ow in
the uplink direction: N=1 (uplink) and M = 1(uplink). The TCP flow has the uplink direction:</dt><dd>N=1 (uplink) and M=1 (uplink). The
start time at t=0s and end time at t=119s.</t> TCP flow has
</list></t> start time at t=0s and end time at t=119s.</dd>
</dl>
</section> </section>
<section numbered="true" toc="default">
<section title="Expected behavior"> <name>Expected Behavior</name>
<dl spacing="normal">
<t><list style="symbols"> <dt>Single uplink RTP-based media flow:</dt>
<t>Single uplink RTP-based media flow: the candidate algorithm is expected <dd>The candidate algorithm is expected
to detect the path capacity constraint, to converge to the bottleneck li nk to detect the path capacity constraint, to converge to the bottleneck li nk
capacity, and to adapt the flow to avoid unwanted oscillations when the capacity, and to adapt the flow to avoid unwanted oscillations when the
sending bit rate is approaching the bottleneck link capacity. No excessi ve sending bit rate is approaching the bottleneck link capacity. No excessi ve
oscillations in the media rate should be present.</t> oscillations in the media rate should be present.</dd>
<dt>Bidirectional RTP-based media flows:</dt>
<t>Bi-directional RTP-based media flows: the candidate algorithm is expect <dd>The candidate algorithm is expected
ed
to converge to the bottleneck capacity of the wired path in both directi ons to converge to the bottleneck capacity of the wired path in both directi ons
despite the presence of measurement noise over the Wi-Fi connection. In the despite the presence of measurement noise over the Wi-Fi connection. In the
presence of background TCP or CBR over UDP traffic, the rate of RTP-base d media presence of background TCP or CBR over UDP traffic, the rate of RTP-base d media
flows should adapt promptly to the arrival and departure of background flows should adapt promptly to the arrival and departure of background
traffic flows.</t> traffic flows.</dd>
<dt>One RTP-based media flow competing with long-lived TCP flow in the uplin
<t>One RTP-based media flow competing with long-live TCP flow in the uplin k
k direction:</dt><dd>The candidate algorithm is expected to avoid
direction: the candidate algorithm is expected to avoid congestion colla congestion collapse
pse and to stabilize at a fair share of the bottleneck link capacity.</dd>
and to stabilize at a fair share of the bottleneck link capacity.</t> </dl>
</list></t> </section>
</section>
</section> <section numbered="true" toc="default">
<name>Bottleneck in Wi-Fi Network</name>
</section> <t>The test cases in this section assume that the wired segment along th
e
<section title="Bottleneck in Wi-Fi Network"> media path is well-provisioned, whereas the bottleneck exists over the
<t>The test cases in this section assume that the wired segment along the
media path is well-provisioned whereas the bottleneck exists over the
Wi-Fi access network. This is to mimic the application scenarios typically Wi-Fi access network. This is to mimic the application scenarios typically
encountered by users in an enterprise environment or at a coffee house.</t> encountered by users in an enterprise environment or at a coffee house.</t>
<section numbered="true" toc="default">
<name>Network Topology</name>
<t>Same as defined in <xref target="sec-wifi-wired-bottleneck-topo" fo
rmat="default"/>.</t>
</section>
<section numbered="true" toc="default">
<name>Test/Simulation Setup</name>
<dl spacing="normal">
<dt>Test duration:</dt><dd>120 s</dd>
<dt>Wi-Fi network characteristics:</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Radio propagation model:</dt><dd>Log-distance path l
oss propagation model (see <xref target="NS3WiFi" format="default"/>)</dd>
<dt>PHY- and MAC-layer configuration:</dt><dd>IEEE 802.1
1n</dd>
<dt>MCS Index at 11:</dt><dd>Raw data rate at 52 Mbps,
16-QAM (Quadrature amplitude modulation) and 1/2
coding rate</dd>
</dl>
</dd>
<dt>Wired path characteristics:</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Path capacity:</dt><dd>100 Mbps</dd>
<dt>One-Way propagation delay:</dt><dd>50 ms</dd>
<dt>Maximum end-to-end jitter:</dt><dd>30 ms</dd>
<dt>Bottleneck queue type:</dt><dd>Drop tail</dd>
<dt>Bottleneck queue size:</dt><dd>300 ms</dd>
<dt>Path loss ratio:</dt><dd>0%</dd>
</dl>
</dd>
<dt>Application characteristics</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Media traffic:</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Media type:</dt><dd>Video</dd>
<dt>Media direction:</dt><dd>See <xref target="s
ubsec-4-2-3" format="default"/></dd>
<dt>Number of media sources (N):</dt><dd>See <xr
ef target="subsec-4-2-3" format="default"/></dd>
<dt>Media timeline:</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Start time:</dt><dd> 0 s</dd>
<dt>End time:</dt><dd> 119 s</dd>
</dl>
</dd>
</dl>
</dd>
<dt>Competing traffic:</dt>
<dd><t><br/></t>
<dl spacing="normal">
<dt>Type of sources:</dt><dd> long-lived TCP or
CBR over UDP</dd>
<dt>Number of sources (M):</dt><dd> See <xref ta
rget="subsec-4-2-3" format="default"/></dd>
<dt>Traffic direction:</dt><dd> See <xref target
="subsec-4-2-3" format="default"/></dd>
<dt>Congestion control:</dt><dd> Default TCP con
gestion control <xref target="RFC5681" format="default"/> or CBR traffic over UD
P</dd>
<dt>Traffic timeline:</dt><dd> See <xref target=
"subsec-4-2-3" format="default"/></dd>
</dl>
</dd>
</dl>
</dd>
</dl>
<section title="Network topology"> </section>
<section anchor="subsec-4-2-3" numbered="true" toc="default">
<t>Same as defined in <xref target="sec-wifi-wired-bottleneck-topo"></xref>< <name>Typical Test Scenarios</name>
/t> <t>This section describes a few test scenarios that are deemed as impo
rtant for
</section>
<section title="Test/simulation setup">
<t><list style="symbols">
<t>Test duration: 120s</t>
<t>Wi-Fi network characteristics:
<list style="symbols">
<t>Radio propagation model: Log-distance path loss propagation
model (see <xref target="NS3WiFi"></xref>)</t>
<t>PHY- and MAC-layer configuration: IEEE 802.11n</t>
<t>MCS Index at 11: 16-QAM 1/2, Raw Data Rate at 52Mbps</t>
</list></t>
<t>Wired path characteristics:
<list style="symbols">
<t>Path capacity: 100Mbps.</t>
<t>One-Way propagation delay: 50ms.</t>
<t>Maximum end-to-end jitter: 30ms.</t>
<t>Bottleneck queue type: Drop tail.</t>
<t>Bottleneck queue size: 300ms.</t>
<t>Path loss ratio: 0%.</t>
</list></t>
<t>Application characteristics:
<list style="symbols">
<t>Media Traffic:
<list style="symbols">
<t>Media type: Video</t>
<t>Media direction: See <xref target="subsec-4-2-3"></xref>.</t>
<t>Number of media sources (N): See <xref target="subsec-4-2-3"></xref
>.</t>
<t>Media timeline:
<list style="symbols">
<t>Start time: 0s.</t>
<t>End time: 119s.</t>
</list></t>
</list></t>
<t>Competing traffic:
<list style="symbols">
<t>Type of sources: long-lived TCP or CBR over UDP.</t>
<t>Number of sources (M): See <xref target="subsec-4-2-3"></xref>.</
t>
<t>Traffic direction: See <xref target="subsec-4-2-3"></xref>.</t>
<t>Congestion control: Default TCP congestion control <xref target="
RFC5681"/>
or constant-bit-rate (CBR) traffic over UDP.</t>
<t>Traffic timeline: See <xref target="subsec-4-2-3"></xref>.</t>
</list></t>
</list></t>
</list></t>
</section>
<section anchor = "subsec-4-2-3" title="Typical test scenarios">
<t>This section describes a few test scenarios that are deemed as importa
nt for
understanding the behavior of a candidate RTP-based congestion control schem e understanding the behavior of a candidate RTP-based congestion control schem e
over a Wi-Fi network. </t> over a Wi-Fi network. </t>
<dl spacing="normal">
<t><list style="letters"> <dt>Multiple RTP-based media flows sharing the wireless downlink:<
<t>Multiple RTP-based media flows sharing the wireless downlink: N=16 (all d /dt><dd> N=16 (all downlink);
ownlink); M=0. This test case is for studying the impact of contention on the multip
M = 0. This test case is for studying the impact of contention on the mult le
iple
concurrent media flows. For an 802.11n network, given the MCS Index of 11 and the concurrent media flows. For an 802.11n network, given the MCS Index of 11 and the
corresponding link rate of 52Mbps, the total application-layer throughput corresponding link rate of 52 Mbps, the total application-layer throughput
(assuming (assuming
reasonable distance, low interference and infrequent contentions caused by reasonable distance, low interference, and infrequent contentions caused b
competing y competing
streams) is around 20Mbps. A total of N=16 RTP-based media flows (with a m streams) is around 20 Mbps. A total of N=16 RTP-based media flows (with a
aximum maximum
rate of 1.5Mbps each) are expected to saturate the wireless interface in t rate of 1.5 Mbps each) are expected to saturate the wireless interface in
his experiment. this experiment.
Evaluation of a given candidate scheme should focus on whether the downlin k media Evaluation of a given candidate scheme should focus on whether the downlin k media
flows can stabilize at a fair share of the total application-layer through flows can stabilize at a fair share of the total application-layer through
put.</t> put.</dd>
<dt>Multiple RTP-based media flows sharing the wireless uplink: </dt><dd>N=16
<t>Multiple RTP-based media flows sharing the wireless uplink: N = 16 (all u (all uplink);
plink); M=0. When multiple clients attempt to transmit media packets uplink over t
M = 0. When multiple clients attempt to transmit media packets uplink over he
the
Wi-Fi network, they introduce more frequent contentions and potential coll isions. Wi-Fi network, they introduce more frequent contentions and potential coll isions.
Per-flow throughput is expected to be lower than that in the previous down link-only Per-flow throughput is expected to be lower than that in the previous down link-only
scenario. Evaluation of a given candidate scheme should focus on whether t he uplink scenario. Evaluation of a given candidate scheme should focus on whether t he uplink
flows can stabilize at a fair share of the total application-layer through flows can stabilize at a fair share of the total application-layer through
put.</t> put.</dd>
<dt>Multiple bidirectional RTP-based media flows:</dt><dd> N=16 (8 uplink and
<t>Multiple bi-directional RTP-based media flows: N = 16 (8 uplink and 8 dow 8 downlink);
nlink); M=0. The goal of this test is to evaluate the performance of the candidat
M = 0. The goal of this test is to evaluate the performance of the candid e scheme
ate scheme in terms of bandwidth fairness between uplink and downlink flows.</dd>
in terms of bandwidth fairness between uplink and downlink flows.</t> <dt>Multiple bidirectional RTP-based media flows with on-off CBR traffic over
UDP:</dt><dd>
<t>Multiple bi-directional RTP-based media flows with on-off CBR traffic ove N=16 (8 uplink and 8 downlink); M=5 (uplink). The goal of this test is to
r UDP: evaluate
N = 16 (8 uplink and 8 downlink); M = 5 (uplink). The goal of this test is
to evaluate
the adaptation behavior of the candidate scheme when its available bandwid th changes the adaptation behavior of the candidate scheme when its available bandwid th changes
due to the departure of background traffic. The background traffic consist s of several due to the departure of background traffic. The background traffic consist s of several
(e.g., M=5) CBR flows transported over UDP. These background flows are ON at time (e.g., M=5) CBR flows transported over UDP. These background flows are ON at time
t=0-60s and OFF at time t=61-120s.</t> t=0-60s and OFF at time t=61-120s.</dd>
<dt>Multiple bidirectional RTP-based media flows with off-on CBR traffic over
<t>Multiple bi-directional RTP-based media flows with off-on CBR traffic ove UDP:</dt><dd>
r UDP: N=16 (8 uplink and 8 downlink); M=5 (uplink). The goal of this test is to
N = 16 (8 uplink and 8 downlink); M = 5 (uplink). The goal of this test is evaluate
to evaluate
the adaptation behavior of the candidate scheme when its available bandwid th changes the adaptation behavior of the candidate scheme when its available bandwid th changes
due to the arrival of background traffic. The background traffic consists of several due to the arrival of background traffic. The background traffic consists of several
(e.g., M=5) parallel CBR flows transported over UDP. These background flow s are OFF at (e.g., M=5) parallel CBR flows transported over UDP. These background flow s are OFF at
time t=0-60s and ON at times t=61-120s.</t> time t=0-60s and ON at times t=61-120s.</dd>
<dt>Multiple bidirectional RTP-based media flows in the presence of background
<t>Multiple bi-directional RTP-based media flows in the presence of backgrou TCP traffic:</dt><dd>
nd TCP traffic: N=16 (8 uplink and 8 downlink); M=5 (uplink). The goal of this test is to
N=16 (8 uplink and 8 downlink); M = 5 (uplink). The goal of this test is t evaluate how
o evaluate how
RTP-based media flows compete against TCP over a congested Wi-Fi network f or a given RTP-based media flows compete against TCP over a congested Wi-Fi network f or a given
candidate scheme. TCP flows have start time at t=40s and end time at t=80 candidate scheme. TCP flows have start time at t=40s and end time at t=80
s. </t> s. </dd>
<dt>Varying number of RTP-based media flows: </dt><dd>A series of tests can be
<t>Varying number of RTP-based media flows: A series of tests can be carried carried out for the
out for the above test cases with different values of N, e.g., N=[4, 8, 12, 16, 20]. T
above test cases with different values of N, e.g., N = [4, 8, 12, 16, 20]. he goal of
The goal of
this test is to evaluate how a candidate scheme responds to varying traffi c load/demand this test is to evaluate how a candidate scheme responds to varying traffi c load/demand
over a congested Wi-Fi network. The start times of the media flows are ran domly distributes over a congested Wi-Fi network. The start times of the media flows are ran domly distributed
within a window of t=0-10s; their end times are randomly distributed withi n a window of within a window of t=0-10s; their end times are randomly distributed withi n a window of
t=110-120s. </t> t=110-120s. </dd>
</dl>
</list></t> </section>
</section> <section numbered="true" toc="default">
<name>Expected Behavior</name>
<section title="Expected behavior"> <dl spacing="normal">
<dt>Multiple downlink RTP-based media flows:</dt><dd>Each media fl
<t><list style="symbols"> ow is expected to get
<t>Multiple downlink RTP-based media flows: each media flow is expected to g
et
its fair share of the total bottleneck link bandwidth. Overall bandwidth usage its fair share of the total bottleneck link bandwidth. Overall bandwidth usage
should not be significantly lower than that experienced by the same number of should not be significantly lower than that experienced by the same number of
concurrent downlink TCP flows. In other words, the behavior of multiple co ncurrent concurrent downlink TCP flows. In other words, the behavior of multiple co ncurrent
TCP flows will be used as a performance benchmark for this test scenario. The TCP flows will be used as a performance benchmark for this test scenario. The
end-to-end delay and packet loss ratio experienced by each flow should be within end-to-end delay and packet loss ratio experienced by each flow should be within
an acceptable range for real-time multimedia applications.</t> an acceptable range for real-time multimedia applications.</dd>
<dt>Multiple uplink RTP-based media flows:</dt><dd>Overall bandwidth usage by
<t>Multiple uplink RTP-based media flows: overall bandwidth usage by all med all media flows
ia flows
should not be significantly lower than that experienced by the same number of concurrent should not be significantly lower than that experienced by the same number of concurrent
uplink TCP flows. In other words, the behavior of multiple concurrent TCP flows uplink TCP flows. In other words, the behavior of multiple concurrent TCP flows
will be used as a performance benchmark for this test scenario.</t> will be used as a performance benchmark for this test scenario.</dd>
<dt>Multiple bidirectional RTP-based media flows with dynamic backgr
<t>Multiple bi-directional RTP-based media flows with dynamic background tra ound traffic
ffic carrying CBR flows over UDP:</dt><dd>The media flows are expecte
carrying CBR flows over UDP: the media flows are expected to adapt in a ti d to adapt in a timely
mely
fashion to the changes in available bandwidth introduced by the arrival/de parture fashion to the changes in available bandwidth introduced by the arrival/de parture
of background traffic.</t> of background traffic.</dd>
<dt>Multiple bidirectional RTP-based media flows with dynamic backgr
<t>Multiple bi-directional RTP-based media flows with dynamic background tra ound traffic
ffic over TCP:</dt><dd>During the presence of TCP background flows, t
over TCP: during the presence of TCP background flows, the overall bandwid he overall bandwidth usage
th usage
by all media flows should not be significantly lower than those achieved b y the by all media flows should not be significantly lower than those achieved b y the
same number of bi-directional TCP flows. In other words, the behavior of m ultiple same number of bidirectional TCP flows. In other words, the behavior of mu ltiple
concurrent TCP flows will be used as a performance benchmark for this tes t scenario. concurrent TCP flows will be used as a performance benchmark for this tes t scenario.
All downlink media flows are expected to obtain similar bandwidth as each other. All downlink media flows are expected to obtain similar bandwidth as each other.
The throughput of each media flow is expected to decrease upon the arrival of TCP The throughput of each media flow is expected to decrease upon the arrival of TCP
background traffic and, conversely, increase upon their departure. Both re actions background traffic and, conversely, increase upon their departure. Both re actions
should occur in a timely fashion, for example, within 10s of seconds.</t> should occur in a timely fashion, for example, within 10s of seconds.</dd>
<dt>Varying number of bidirectional RTP-based media flows:</dt><dd>The test re
<t>Varying number of bi-directional RTP-based media flows: the test results sults for
for
varying values of N -- while keeping all other parameters constant -- is e xpected varying values of N -- while keeping all other parameters constant -- is e xpected
to show steady and stable per-flow throughput for each value of N. The ave rage to show steady and stable per-flow throughput for each value of N. The ave rage
throughput of all media flows is expected to stay constant around the maxi mum rate throughput of all media flows is expected to stay constant around the maxi mum rate
when N is small, then gradually decrease with increasing value of N till i t reaches when N is small, then gradually decrease with increasing value of N till i t reaches
the minimum allowed rate, beyond which the offered load to the Wi-Fi netwo rk exceeds the minimum allowed rate, beyond which the offered load to the Wi-Fi netwo rk exceeds
its capacity (i.e., with a very large value of N).</t> its capacity (i.e., with a very large value of N).</dd>
</dl>
</list></t> </section>
</section> </section>
<section numbered="true" toc="default">
</section> <name>Other Potential Test Cases</name>
<section anchor="sec-edca-wmm-usage" numbered="true" toc="default">
<section title="Other Potential Test Cases"> <name>EDCA/WMM usage</name>
<t>The EDCA/WMM mechanism defines prioritized QoS for four traffic cla
<section anchor="sec-edca-wmm-usage" title="EDCA/WMM usage"> sses
<t>The EDCA/WMM mechanism defines prioritized QoS for four traffic classes
(or Access Categories). RTP-based real-time media flows should achieve bette r (or Access Categories). RTP-based real-time media flows should achieve bette r
performance in terms of lower delay and fewer packet losses with EDCA/WMM performance in terms of lower delay and fewer packet losses with EDCA/WMM
enabled when competing against non-interactive background traffic such as fi le enabled when competing against non-interactive background traffic such as fi le
transfers. When most of the traffic over Wi-Fi is dominated by media, howeve r, transfers. When most of the traffic over Wi-Fi is dominated by media, howeve r,
turning on WMM may degrade performance since all media flows now attempt turning on WMM may degrade performance since all media flows now attempt
to access the wireless transmission medium more aggressively, thereby causin g to access the wireless transmission medium more aggressively, thereby causin g
more frequent collisions and collision-induced losses. This is a topic worth y more frequent collisions and collision-induced losses. This is a topic worth y
of further investigation.</t> of further investigation.</t>
</section>
</section> <section anchor="sec-legacy-effects" numbered="true" toc="default">
<name>Effect of Heterogeneous Link Rates</name>
<section anchor="sec-legacy-effects" title="Effect of heterogeneous link rates <t>As discussed in <xref target="Heusse2003" format="default"/>, the p
"> resence of clients
<t>As discussed in <xref target="Heusse2003"></xref>, the presence of clients
operating over slow PHY-layer link rates (e.g., a legacy 802.11b device) conne cted operating over slow PHY-layer link rates (e.g., a legacy 802.11b device) conne cted
to a modern network may adversely impact the overall performance of the networ k. to a modern network may adversely impact the overall performance of the networ k.
Additional test cases can be devised to evaluate the effect of clients with he terogeneous Additional test cases can be devised to evaluate the effect of clients with he terogeneous
link rates on the performance of the candidate congestion control algorithm. S uch link rates on the performance of the candidate congestion control algorithm. S uch
test cases, for instance, can specify that the PHY-layer link rates for all cl ients test cases, for instance, can specify that the PHY-layer link rates for all cl ients
span over a wide range (e.g., 2Mbps to 54Mbps) for investigating its effect on the span over a wide range (e.g., 2 Mbps to 54 Mbps) for investigating its effect on the
congestion control behavior of the real-time interactive applications.</t> congestion control behavior of the real-time interactive applications.</t>
</section>
</section> </section>
</section>
</section> <section anchor="IANA" numbered="true" toc="default">
<name>IANA Considerations</name>
</section> <t>This document has no IANA actions.</t>
</section>
<section anchor="IANA" title="IANA Considerations"> <section anchor="Security" numbered="true" toc="default">
<name>Security Considerations</name>
<t>This memo includes no request to IANA.</t> <t>The security considerations in <xref target="RFC8868" format="default"/
>
</section>
<section anchor="Security" title="Security Considerations">
<t>The security considerations in <xref target="I-D.ietf-rmcat-eval-criteria">
</xref>
and the relevant congestion control algorithms apply. The principles for co ngestion and the relevant congestion control algorithms apply. The principles for co ngestion
control are described in <xref target="RFC2914"></xref>, and in particular, any new control are described in <xref target="RFC2914" format="default"/>, and in p articular, any new
method must implement safeguards to avoid congestion collapse of the Interne t.</t> method must implement safeguards to avoid congestion collapse of the Interne t.</t>
<t>Given the difficulty of deterministic wireless testing, it is recommend
<t>Given the difficulty of deterministic wireless testing, it is recommended a ed and
nd
expected that the tests described in this document would be done via simulat ions. expected that the tests described in this document would be done via simulat ions.
However, in the case where these test cases are carried out in a testbed set ting, However, in the case where these test cases are carried out in a testbed set ting,
the evaluation should take place in a controlled lab environment. In the tes tbed, the evaluation should take place in a controlled lab environment. In the tes tbed,
the applications, simulators and network nodes ought to be well-behaved and should the applications, simulators, and network nodes ought to be well-behaved and should
not impact the desired results. It is important to take appropriate caution to not impact the desired results. It is important to take appropriate caution to
avoid leaking non-responsive traffic with unproven congestion avoidance beha vior onto avoid leaking nonresponsive traffic with unproven congestion avoidance behav ior onto
the open Internet.</t> the open Internet.</t>
</section>
</middle>
<back>
</section> <references>
<name>References</name>
<section title="Contributors"> <references>
<name>Normative References</name>
<t>The following individuals contributed to the design, implementation, and ve <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer
rification ence.RFC.5681.xml"/>
of the proposed test cases during earlier stages of this work. They have hel
ped to
validate and substantially improve this specification. </t>
<t>Ingemar Johansson, &lt;ingemar.s.johansson@ericsson.com&gt; <reference anchor="RFC8868" target="https://www.rfc-editor.org/info/rfc8868">
of Ericsson AB contributing to the description and validation of cellular te <front>
st cases <title>Evaluating Congestion Control for Interactive Real-Time Media</title>
during the earlier stage of this draft.</t>
<t>Wei-Tian Tan, &lt;dtan2@cisco.com&gt;, of Cisco Systems designed and set <author initials='V' surname='Singh' fullname='Varun Singh'>
up <organization />
a Wi-Fi testbed for evaluating parallel video conferencing streams, based </author>
upon which proposed Wi-Fi test cases are described. He also recommended ad
ditional
test cases to consider, such as the impact of EDCA/WMM usage. </t>
<t>Michael A. Ramalho, &lt;mar42@cornell.edu&gt; of AcousticComms Consulting <author initials='J' surname='Ott' fullname='Jörg Ott'>
(previously at Cisco Systems) applied learnings from Cisco's internal expe <organization />
rimentation </author>
to the early versions of the draft. He also worked on validating the propo
sed
test cases in a VM-based lab setting.</t>
</section> <author initials='S' surname='Holmer' fullname='Stefan Holmer'>
<organization />
</author>
<section anchor="Acknowledgments" title="Acknowledgments"> <date month='January' year='2021' />
<t>The authors would like to thank Tomas Frankkila, Magnus Westerlund, </front>
Kristofer Sandlund, Sergio Mena de la Cruz, and Mirja Kuehlewind for their
valuable inputs and review comments regarding this draft.</t>
</section> <seriesInfo name="RFC" value="8868"/>
<seriesInfo name="DOI" value="10.17487/RFC8868"/>
</reference>
</middle> <reference anchor="RFC8867" target="https://www.rfc-editor.org/info/rfc8867">
<front>
<title>Test Cases for Evaluating Congestion Control for Interactive Real-Time Me
dia</title>
<!-- *****BACK MATTER ***** --> <author initials='Z' surname='Sarker' fullname='Zaheduzzaman Sarker'>
<back> <organization />
<!-- References split into informative and normative --> </author>
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s: <organization />
1. define an ENTITY at the top, and use "ampersand character"RFC2629; here </author>
(as shown)
2. simply use a PI "less than character"?rfc include="reference.RFC.2119.xm
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(for I-Ds: include="reference.I-D.narten-iana-considerations-rfc2434bis.
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Both are cited textually in the same manner: by using xref elements. <author initials='X' surname='Zhu' fullname='Xiaoqing Zhu'>
If you use the PI option, xml2rfc will, by default, try to find included fi <organization />
les in the same </author>
directory as the including file. You can also define the XML_LIBRARY enviro
nment variable
with a value containing a set of directories to search. These can be eithe
r in the local
filing system or remote ones accessed by http (http://domain/dir/... ).-->
<references title="Normative References"> <author initials='M' surname='Ramalho' fullname='Michael A. Ramalho'>
<organization />
</author>
<!--?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC. <date month='January' year='2021' />
2119.xml"?--> </front>
<?rfc include='reference.RFC.5681.xml'?>
<?rfc include='reference.RFC.8174.xml'?>
<?rfc include='reference.I-D.ietf-rmcat-eval-criteria.xml'?> <seriesInfo name="RFC" value="8867"/>
<seriesInfo name="DOI" value="10.17487/RFC8867"/>
<?rfc include='reference.I-D.ietf-rmcat-eval-test.xml'?> </reference>
<reference anchor="HO-deploy-3GPP" <reference anchor="HO-deploy-3GPP" target="http://www.3gpp.org/ftp/specs
target="http://www.3gpp.org/ftp/specs/archive/25_series/25.814/ /archive/25_series/25.814/25814-710.zip">
25814-710.zip"> <front>
<front> <title>Physical layer aspects for evolved Universal Terrestrial
<title>Physical layer aspects for evolved Universal Terrestrial
Radio Access (UTRA)</title> Radio Access (UTRA)</title>
<author>
<organization>3GPP</organization>
</author>
<date month="October" year="2006"/>
</front>
<seriesInfo name="TS" value="25.814"/>
</reference>
<author fullname="3GPP R1" initials="3GPP" surname="TS 25.814"> <reference anchor="IEEE802.11" target="https://ieeexplore.ieee.org/docum
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</author> <front>
<title>Standard for Information technology--Telecommunications and
<date month="October" year="2006" />
</front>
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<reference anchor="IEEE802.11">
<front>
<title>Standard for Information technology--Telecommunications and
information exchange between systems Local and metropolitan area information exchange between systems Local and metropolitan area
networks--Specific requirements Part 11: Wireless LAN Medium Access networks--Specific requirements Part 11: Wireless LAN Medium Access
Control (MAC) and Physical Layer (PHY) Specifications</title> Control (MAC) and Physical Layer (PHY) Specifications</title>
<author>
<organization>IEEE</organization>
</author>
</front>
<seriesInfo name="IEEE" value="802.11-2012"/>
</reference>
<author fullname="IEEE"> <reference anchor="NS3WiFi" target="https://www.nsnam.org/doxygen/classn
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</author> <front>
<title>ns3::YansWifiChannel Class Reference</title>
<date year="2012" /> <author/>
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</references>
<reference anchor="NS3WiFi" <references>
target="https://www.nsnam.org/doxygen/classns3_1_1_yans_wifi_ch <name>Informative References</name>
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<front>
<title>Wi-Fi Channel Model in ns-3 Simulator</title>
<author></author>
<date />
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<reference anchor="HO-def-3GPP"
target="http://www.3gpp.org/ftp/specs/archive/21_series/21.905/
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<front>
<title>Vocabulary for 3GPP Specifications</title>
<author fullname="3GPP SA" initials="3GPP" surname="TR 21.905">
<organization>3GPP</organization>
</author>
<date month="December" year="2009" />
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</reference>
<reference anchor="HO-LTE-3GPP"
target="http://www.3gpp.org/ftp/specs/archive/36_series/36.331/
36331-990.zip">
<front>
<title>E-UTRA- Radio Resource Control (RRC); Protocol
specification</title>
<author fullname="3GPP R2" initials="3GPP" surname="TS 36.331">
<organization>3GPP</organization>
</author>
<date month="December" year="2011" />
</front>
</reference>
<reference anchor="HO-UMTS-3GPP"
target="http://www.3gpp.org/ftp/specs/archive/25_series/25.331/
25331-990.zip">
<front>
<title>Radio Resource Control (RRC); Protocol specification</title>
<author fullname="3GPP R2" initials="3GPP" surname="TS 25.331">
<organization>3GPP</organization>
</author>
<date month="December" year="2011" />
</front>
</reference>
<reference anchor="QoS-3GPP"
target="http://www.3gpp.org/ftp/specs/archive/23_series/23.203/
23203-990.zip">
<front>
<title>Policy and charging control architecture</title>
<author fullname="3GPP S2" initials="3GPP" surname="TS 23.203">
<organization></organization>
</author>
<date month="June" year="2011" />
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<reference anchor="NS-2" target="http://nsnam.sourceforge.net/wiki/index.p
hp/Main_Page">
<front>
<title>ns-2</title>
<author>
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<date month="December" year="2014"/>
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<reference anchor="NS-3" target="https://www.nsnam.org/"> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/referen
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<author> <reference anchor="HO-def-3GPP" target="http://www.3gpp.org/ftp/specs/ar
<organization></organization> chive/21_series/21.905/21905-940.zip">
</author> <front>
<date /> <title>Vocabulary for 3GPP Specifications</title>
</front> <author>
</reference> <organization>3GPP</organization>
</author>
<date month="December" year="2009"/>
</front>
<seriesInfo name="3GPP TS" value="21.905"/>
</reference>
<reference anchor="Heusse2003" target=""> <reference anchor="HO-LTE-3GPP" target="http://www.3gpp.org/ftp/specs/ar
<front> chive/36_series/36.331/36331-990.zip">
<title>Performance anomaly of 802.11b</title> <front>
<title>Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Re
source Control (RRC); Protocol specification</title>
<author>
<organization>3GPP</organization>
</author>
<date month="December" year="2011"/>
</front>
<seriesInfo name="3GPP TS" value="36.331"/>
</reference>
<author fullname="Martin Heusse" initials="M." surname="Heusse"> <reference anchor="HO-UMTS-3GPP" target="http://www.3gpp.org/ftp/specs/a
<organization></organization> rchive/25_series/25.331/25331-990.zip">
</author> <front>
<title>Radio Resource Control (RRC); Protocol specification</title>
<author>
<organization>3GPP</organization>
</author>
<date month="December" year="2011"/>
</front>
<seriesInfo name="3GPP TS" value="25.331"/>
</reference>
<author fullname="Franck Rousseau" initials="F." surname="Rousseau"> <reference anchor="QoS-3GPP" target="http://www.3gpp.org/ftp/specs/archi
<organization></organization> ve/23_series/23.203/23203-990.zip">
</author> <front>
<title>Policy and charging control architecture</title>
<author>
<organization>3GPP</organization>
</author>
<date month="June" year="2011"/>
</front>
<seriesInfo name="3GPP TS" value="23.203"/>
</reference>
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<organization></organization> <front>
</author> <title>ns-2</title>
<author>
<organization/>
</author>
<date month="December" year="2014"/>
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<author fullname="Andrzej Duda" initials="A." surname="Duda"> <reference anchor="NS-3" target="https://www.nsnam.org/">
<organization></organization> <front>
</author> <title>ns-3 Network Simulator</title>
<date month="March" year="2003"/> <author>
<organization/>
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</front>
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</front> <reference anchor="Heusse2003" target="https://ieeexplore.ieee.org/docum
<seriesInfo ent/1208921">
name="in Proc. 23th Annual Joint Conference of the IEEE Computer and Com <front>
munications Societies," <title>Performance anomaly of 802.11b</title>
value = "(INFOCOM'03)"/> <author fullname="Martin Heusse" initials="M." surname="Heusse">
<organization/>
</author>
<author fullname="Franck Rousseau" initials="F." surname="Rousseau">
<organization/>
</author>
<author fullname="Gilles Berger-Sabbatel" initials="G." surname="Ber
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<organization/>
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<author fullname="Andrzej Duda" initials="A." surname="Duda">
<organization/>
</author>
<date month="March" year="2003"/>
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<refcontent>Twenty-second Annual Joint Conference of the IEEE Comput
er and Communications Societies</refcontent>
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</reference> <section numbered="false" toc="default">
</references> <name>Contributors</name>
<t>The following individuals contributed to the design, implementation, an
d verification
of the proposed test cases during earlier stages of this work. They have hel
ped to
validate and substantially improve this specification. </t>
<t><contact fullname="Ingemar Johansson"/> &lt;ingemar.s.johansson@ericsso
n.com&gt;
of Ericsson AB contributed to the description and validation of cellular tes
t cases
during the earlier stage of this document.</t>
<t><contact fullname="Wei-Tian Tan"/> &lt;dtan2@cisco.com&gt; of Cisco Sys
tems designed and set up
a Wi-Fi testbed for evaluating parallel video conferencing streams, based
upon which proposed Wi-Fi test cases are described. He also recommended ad
ditional
test cases to consider, such as the impact of EDCA/WMM usage. </t>
<t><contact fullname="Michael A. Ramalho"/> &lt;mar42@cornell.edu&gt; of A
cousticComms Consulting
(previously at Cisco Systems) applied lessons from Cisco's internal experi
mentation
to the draft versions of the document. He also worked on validating the pr
oposed
test cases in a virtual-machine-based lab setting.</t>
</section>
<section anchor="Acknowledgments" numbered="false" toc="default">
<name>Acknowledgments</name>
<t>The authors would like to thank
<contact fullname="Tomas Frankkila"/>,
<contact fullname="Magnus Westerlund"/>,
<contact fullname="Kristofer Sandlund"/>,
<contact fullname="Sergio Mena de la Cruz"/>, and
<contact fullname="Mirja Kühlewind"/> for their
valuable inputs and review comments regarding this document.</t>
</section>
</back> </back>
</rfc> </rfc>
 End of changes. 143 change blocks. 
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