Re: [rmcat] Genart last call review of draft-ietf-rmcat-wireless-tests-08

Gyan Mishra <> Thu, 05 March 2020 22:26 UTC

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From: Gyan Mishra <>
Date: Thu, 5 Mar 2020 17:26:22 -0500
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To: "Xiaoqing Zhu (xiaoqzhu)" <>
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Subject: Re: [rmcat] Genart last call review of draft-ietf-rmcat-wireless-tests-08
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Xiaoqing & authors

I am all set with the authors comments and responses.

Warm regards


On Thu, Feb 27, 2020 at 12:36 PM Xiaoqing Zhu (xiaoqzhu) <>

> Hi Gyan,
> Thanks a lot for your very thorough review of this draft, and for your
> valuable comments. We have uploaded the revised version (-09) to address
> some of the concerns and suggestions you've raised.
> Please also see our replies below inline, tagged [authors].  Let us know
> if you have any further thoughts or comments __
> Best Regards,
> Xiaoqing, on behalf of all authors.
> On 1/21/20, 3:46 PM, "Gyan Mishra via Datatracker" <>
> wrote:
>     Reviewer: Gyan Mishra
>     Review result: Ready with Issues
>     I am the assigned Gen-ART reviewer for this draft. The General Area
>     Review Team (Gen-ART) reviews all IETF documents being processed
>     by the IESG for the IETF Chair.  Please treat these comments just
>     like any other last call comments.
>     For more information, please see the FAQ at
>     <>.
>     Reviewer: Gyan Mishra
>     Review result: Ready with Minor Issues
>     Document: draft-ietf-rmcat-wireless-tests-08
>     Reviewer: Gyan Mishra
>     Review Date: 2020-01-17
>     IETF LC End Date: 2020-01-21
>     IESG Telechat date: Not scheduled for a telechat
>     Summary: Ready, but with nits and minor issues that should be
> addressed.
>     Major issues: None
>     Minor issues:  This document describes test cases for evaluating
> performance of
>     RTP congestion control algorithms over LTE & WIFI networks.
>     Section 1 It is mentioned a number of instance where “wired” is
> mentioned where
>     I believe “wireless” or “WIFI” is what is meant to be stated.  Please
> check.
> [authors] Thanks for raising this concern. We’ve doubled checked on the
> usage of “wired” in all three instances in the introduction section, and
> believe it is intended as such.  Our intention was to contrast the
> characteristics of wireless networks from those of wired networks, as a
> motivation of the need for this draft.   We have, however, taken the
> opportunity to revise those sentences to make them less wordy.
>     I would recommend  to use WIFI to refer to local LAN WIFI and use
> cellular to
>     refer to a mobile handset, and not use the term “wireless” as that
> could be
>     confusing.
> [authors] We agree with the suggestion that it is preferable to refer
> specifically to WiFi or cellular whenever possible and have mostly edited
> out the word “wireless”. In a few places, however, it is rather cumbersome
> to always say “cellular and WiFi networks” when our intention is to simply
> contrast the difference between wireless and wired communication. We have
> therefore stuck with the term “wireless” in those cases.
>     I would recommend not using LTE to refer to Cellular from a general
> mobile
>     handset point of view, since LTE refers to 4G and Cellular could be
> any -
>     2G,3G,4G,5G etc
> [authors]  We agree with this proposed change. The text has been updated
> accordingly with a few exceptions: a) mentioning LTE/5G as an example of
> operational cellular network; b) pointing to the LTE simulator in NS-3; and
> c) referencing the corresponding 3GPP standard documents.
>     Section 3 This section also mentioned “wired” where I think the goal
> of the
>     document is test cases of WIFI & Cellular and adding in wired does
> confuse the
>     reader as we are talking about quality degradation issues with wireless
>     technologies - WIFI & Cellular.  Please check the verbiage.
> [authors] Thanks for pointing this out. We have checked all three previous
> usage of the word in this section and have eliminated the mention of it in
> the introductory discussions. The remaining two uses, however, are needed
> for describing the proposed test case topology so we left them as is.
>     Section 3 In this sentence you mention 3G support of high bandwidth.
> My
>     experience with 3G has not been very slow page loading and that
> multimedia
>     would suffer.
> [authors] This is a fair complaint. To avoid controversy, we have revised
> the sentence to now state: “… it is evident that only the more recent radio
> technologies can support the high bandwidth requirements  …”
>     Section 3 Bottom of page 5 it is mentioned that the combination of
> multiple
>     access technologies such as one user has LTE connection and another
> has Wi-Fi
>     connection is kept out of the scope of this document.  Please explain
> why as
>     the reader would believe it would be in scope as that is the main
> topic.
> [authors]  When some of the users are on LTE and some of the users are on
> Wi-Fi, it is only interesting to investigate the test case when the
> bottleneck of the system is on the wired hop.  Whereas the main focus of
> this draft is to evaluate how congestion control schemes interactive over
> the wireless interface. We have added the following statement in the draft
> to explain why it is out of scope:
>         “It should be noted that the goal of the following test cases is
> to evaluate the performance
>         of candidate algorithms over the radio interface of the cellular
> network. Hence it is assumed
>         that the radio interface is the bottleneck link between the
> communicating peers and that the core
>         network does not introduce any extra congestion along the path.
> Consequently, this draft has kept
>         as out of scope the combination of multiple access technologies
> involving both cellular and Wi-Fi users.”
>     Section 3 Top of page 6 - I am wondering if there is a better
> explanation of
>     why you need a test simulator due to unpredictable nature or cellular
> other
>     than underground mines.
> [authors]  The unpredictable nature of the cellular networks makes test
> results unrepeatable. Therefore our recommendation of carrying out tests
> using simulators.
>     Section 3.1.1 Here the fixed user is on a wired LAN connected to
> mobile user.
>     You mention wireless interface which makes me wonder is the fixed user
> actually
>     a WIFI user connected to broadband WIFI router wired to the internet.
> See in
>     quotes which makes me wonder "The fixed user is connected to the
> Internet via
>     wired connection with sufficiently high bandwidth, for instance, 10
> Gbps, so
>     that the system is resource limited on the {wireless?} interface"
> [authors]  Thanks for raising this point of confusion. The proposed test
> case comprise of both cellular users and fixed users. They share the wired
> backhaul link with sufficiently high bandwidth.  As such, the bottleneck of
> the system is over the cellular radio access link.  We have revised the
> sentence as below to avoid further confusion:
> “… so that the system bottleneck is on the cellular radio access interface
> … “
>     Section 4.1 Please explain in why the home access link represents a
> bottleneck
>     due to its bandwidth. It is not obvious as these days Gigabit and above
>     broadband speeds are available at home.
> [authors] We agree that the scenario where the wired hop remains the
> bottleneck is becoming less common. This subsection describes test cases to
> reflect DSL-like home Internet access that's less common but still present
> especially in other parts of the world.   As acknowledged in this section,
> these test cases are proposed mainly as a sanity check. Over time, we can
> perhaps get rid of this section completely.
>     Nits/editorial comments:
>     Draft Date should to be updated.
> [authors] Done
>     Section 3.1.2  1-B Antenna- [2D, 3D] should be defined
> [authors]  The cited reference of the 3GPP test plan contains information
> for the above terminology.  For this round of revision we have not gathered
> input from authors familiar with the cellular technology terminologies. We
> will try to update the definition directly in the text in a later revision.
>     Section 3.1.2 RTT [40, 150] , should define a unit millisecond
> [authors] Done.
>     Section 3.1.2 4. User Intensity, should define what the values in
> brackets mean
>     and unit of measure.
> [authors]  The cited reference of the 3GPP test plan contains information
> for the above terminology.  For this round of revision we have not gathered
> input from authors familiar with the cellular technology terminologies. We
> will try to update the definition directly in the text in a later revision.
>  Section 3.1.2 7.2.a Media direction: Uplink and Downlink,   should define
> what is meant by Uplink and Downlink
> [authors] The definition has been provided in the second paragraph of
> Section 3.1.1 as well as in the illustration in Fig. 1.
> Section 4.2.3 g N= [4, 8,  12, 16, 20], should define what N is and any
> unit of measure
> [authors] The variables N and M indicate the number of real-time media
> flows and competing TCP streams, respectively, as illustrated in Fig. 2. We
> added a sentence in Sec. 4.1.1 to explicitly explain this
>     _______________________________________________
>     Gen-art mailing list
> --

Gyan  Mishra

Network Engineering & Technology


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Phone: 301 502-1347