Congestion Control Requirements for Interactive Real-Time Media
draft-ietf-rmcat-cc-requirements-09

[Ballot comment]
This is a clear, readable document that I think will be useful to people trying to understand what work is being done and why.  Thanks for doing it!

[Ballot comment]
= Section 2 =
"The algorithm must consider the case where offered loads are
            less than the available bandwidth at any given moment, and
            may vary dramatically over time"

A requirement for an algorithm to "consider the case" seems a bit odd and makes me wonder what the real requirement is.

[Ballot comment]
Thanks for addressing the SecDir reviewers comments and adding text to the security considerations section to reflect the possible impact of such attacks.  I see Spencer's response that a sentence or two will be added, but don't see an actual change from the -05 draft.

Here is Steve's recommendation that Spencer agreed with and I think it would be helpful (but only have this as a comment as it's not something to block on, but could improve the section):

However, I think that one sentence should probably be added. The section says “Attacks that increase the perceived available bandwidth are conceivable, and need to be evaluated.”  While this is true (and disregarding the spelling errors for the moment), I believe it is the most concerning part of the security considerations section and therefore deserves more attention. I suggest adding a sentence reflecting on the possible impact of such attacks. For example, this sentence could be added after the one that I just quoted: “Such attacks could result in starvation of competing flows and permit amplification attacks.” Adding such a sentence may provide guidance to readers who are congestion control experts not familiar with security and therefore not likely to understand the implications of the existing, brief text.

https://www.ietf.org/mail-archive/web/secdir/current/msg04972.html

Thank you!

[Ballot comment]
I have been on record as saying that publishing these "requirements documents" as RFCs is bad practice.  They serve no purpose as standalone documents.  Requirements are living entities until the protocol specification that satisfies them is published.  I would rather see these maintained in a wiki or living I-D and either not published or published as an appendix to the corresponding protocol specification.

That being said, I will not stand in the way of this document.

[Ballot comment]
I have no objection to the publication of this document, but I found the reference to routing changes in Section 2 bullet 1,C to be peculiar. While it is true that "routing changes" may alter or remove bottlenecks or change the bandwidth available, a change in routing might have no affect on these things. I wonder whether you really want to talk about
reacting to changes in bottlenecks and available bandwidth rather than changes in routing? That is, you don't actually care what has caused the change to the measures that lead to congestion: you care about the congestion itself. For example, if you were operating over a variable bandwidth link (such as a microwave link) the changes could arise without any routing change.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Informational. The document specifies requirements for real-time media congestion control and thus is informational for congestion control designers and a basis for the evaluation of these algorithms.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

The documents describes requirements for real-time media congestion control. With the standardization of RTCweb, an increasing amount of real-time media is expected in the Internet and thus it's important that this traffic is congestion controlled. Real-time media traffic has quite different requirements on congestion control than most the other Internet traffic. The requirements are listed in this document to develop and, later, evaluate one or more congestion control schemes that are more suitable to real-time media traffic than today's existing schemes.

Working Group Summary:

There was quite a lot discussion in the working group on how to define fairness (mainly in respect to evaluation criteria document). For this document the working group concluded to leave the definition of fairness open (to the evaluation criteria document). Only self-fairness was defined (as roughly equal bandwidth). Further there was a discussion on RTT-fairness. This was added as an optional requirement ("if possible").

Additionally this document address requirements to handle different RTP stream multiplexed into one connection (5-tuple) or different DSCP marking within one connection. Those points where discussed on the RTPweb as well as on the rmcat mailing list.

As an outcome of the WGLC and IESG Review process additional text on deficiencies of existing mechanisms discussing TFRC as well as further details on jitter and interactions with circuit breakers have been added. To timely address the comments an (additional) editor has been added. Updates have been announced to the working group and no further obligations were received.

Document Quality:

This document is an informational requirements document, therefore there is of course no implementation related to this.

The document received several rounds of reviews in total of 10 different persons (incl. 4 in WGLC and 2 from people mainly working in RTCweb) leading to discussions with even more people involved. These discussions led to several additions and smaller modification to the requirements.

The document contains one normative reference to an RTCweb working group document that is as know to the shepherd is close to publication.

As there is no requirements language in this document, the section on requirements language could be removed.

The structuring of the requirements could still be improved to enhance readability. However, the technical content is well addressed.

Personnel:

Mirja Kuehlewind (mirja.kuehlewind@tik.ee.ethz.ch) is Docoment Shepherd and one of the rmcat working group chairs.
Spencer Dawkins  is the Responsible Area Director

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I briefly reviewed the first version of this w-g doc (-00) to be able to contribute to the discussion on the mailing list. Further I performed a detailed review during wglc (-02) and have been sending it to the mailing list. Further I reviewed the version (-04) to check if various WGLC comments from different reviewers have been addressed. Finial I reread the final (-08) to check if everything is understandable and the open issues have been well addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No. A sufficient number of reviews for the whole document have been performed addressing all kind of issues regarding the content, completeness, comprehensibility as well as the wording and terminology. Further, an additional document editor has been added to ensure that the review comments have been well addressed.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

This document is informational. I don't see any security or operational issues. In fact I don't think the security consideration section is needed here, as it currently only discusses general issues on congestion control not specific to real-time media congestion control.

The document already received two reviews from the RTCweb working group (in WGLC).

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

There are no open issues that are discussed in the working group. From my personal view some sub-bullets in the requirements seems slightly redundant but that doesn't prevent a good understanding of the document.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

Yes, the authors (incl. the new editor) confirmed that no IPR exists.

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The working group as a whole agreed on this document as this is the basis for further documents.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

All nits have been resolved.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, media type, and URI type reviews.

Does not apply.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

Yes. Normative reference to [I-D.ietf-rtcweb-overview]. As far as known by the shepherd, this document is close to publication (in WGCL?) and therefore this should not be an problem. However, alternatively the (few) needed terminology could be integrated into this document and therefore the reference could be removed.

(15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 5226).

IANA section exists but no considerations required for this document. Thus should be removed before publication.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

None.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, etc.

Does not apply to this document.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Informational. The document specifies requirements for real-time media congestion control and thus is informational for congestion control designers and a basis for the evaluation of these algorithms.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

The documents describes requirements for real-time media congestion control. With the standardization of RTCweb, an increasing amount of real-time media is expected in the Internet and thus it's important that this traffic is congestion controlled. Real-time media traffic has quite different requirements on congestion control than most the other Internet traffic. The requirements are listed in this document to develop and, later, evaluate one or more congestion control schemes that are more suitable to real-time media traffic than today's existing schemes.

Working Group Summary:

There was quite a lot discussion in the working group on how to define fairness (mainly in respect to evaluation criteria document). For this document the working group concluded to leave the definition of fairness open (to the evaluation criteria document). Only self-fairness was defined (as roughly equal bandwidth). Further there was a discussion on RTT-fairness. This was added as an optional requirement ("if possible").

Additionally this document address requirements to handle different RTP stream multiplexed into one connection (5-tuple) or different DSCP marking within one connection. Those points where discussed on the RTPweb as well as on the rmcat mailing list.

As an outcome of the WGLC and IESG Review process additional text on deficiencies of existing mechanisms discussing TFRC as well as further details on jitter and interactions with circuit breakers have been added. To timely address the comments an (additional) editor has been added. Updates have been announced to the working group and no further obligations were received.

Document Quality:

This document is an informational requirements document, therefore there is of course no implementation related to this.

The document received several rounds of reviews in total of 10 different persons (incl. 4 in WGLC and 2 from people mainly working in RTCweb) leading to discussions with even more people involved. These discussions led to several additions and smaller modification to the requirements.

The document contains one normative reference to an RTCweb working group document that is as know to the shepherd is close to publication.

As there is no requirements language in this document, the section on requirements language could be removed.

The structuring of the requirements could still be improved to enhance readability. However, the technical content is well addressed.

Personnel:

Mirja K¸hlewind (mirja.kuehlewind@ikr.uni-stuttgart.de) is Docoment Shepherd and one of the rmcat working group chairs.
Spencer Dawkins  is the Responsible Area Director

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I briefly reviewed the first version of this w-g doc (-00) to be able to contribute to the discussion on the mailing list. Further I performed a detailed review during wglc (-02) and have been sending it to the mailing list. Further I reviewed the version (-04) to check if various WGLC comments from different reviewers have been addressed. Finial I reread the final (-08) to check if everything is understandable and the open issues have been well addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No. A sufficient number of reviews for the whole document have been performed addressing all kind of issues regarding the content, completeness, comprehensibility as well as the wording and terminology. Further, an additional document editor has been added to ensure that the review comments have been well addressed.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

This document is informational. I don't see any security or operational issues. In fact I don't think the security consideration section is needed here, as it currently only discusses general issues on congestion control not specific to real-time media congestion control.

The document already received two reviews from the RTCweb working group (in WGLC).

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

There are no open issues that are discussed in the working group. From my personal view some sub-bullets in the requirements seems slightly redundant but that doesn't prevent a good understanding of the document.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

Yes, the authors (incl. the new editor) confirmed that no IPR exists.

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The working group as a whole agreed on this document as this is the basis for further documents.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

All fixed have been resolved.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, media type, and URI type reviews.

Does not apply.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

Yes. Normative reference to [I-D.ietf-rtcweb-overview]. As far as known by the shepherd, this document is close to publication (in WGCL?) and therefore this should not be an problem. However, alternatively the (few) needed terminology could be integrated into this document and therefore the reference could be removed.

(15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 5226).

IANA section exists but no considerations required for this document. Thus should be removed before publication.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

None.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, etc.

Does not apply to this document.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Informational. The document specifies requirements for real-time media congestion control and thus is informational for congestion control designers and a basis for the evaluation of these algorithms.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

The documents describes requirements for real-time media congestion control. With the standardization of RTCweb, an increasing amount of real-time media is expected in the Internet and thus it's important that this traffic is congestion controlled. Real-time media traffic has quite different requirements on congestion control than most the other Internet traffic. The requirements are listed in this document to develop and, later, evaluate one or more congestion control schemes that are more suitable to real-time media traffic than today's existing schemes.

Working Group Summary:

There was quite a lot discussion in the working group on how to define fairness (mainly in respect to evaluation criteria document). For this document the working group concluded to leave the definition of fairness open (to the evaluation criteria document). Only self-fairness was defined (as roughly equal bandwidth). Further there was a discussion on RTT-fairness. This was added as an optional requirement ("if possible").

Additionally this document address requirements to handle different RTP stream multiplexed into one connection (5-tuple) or different DSCP marking within one connection. Those points where discussed on the RTPweb as well as on the rmcat mailing list.

As an outcome of the WGLC and IESG Review process additional text on deficiencies of existing mechanisms discussing TFRC as well as further details on jitter and interactions with circuit breakers have been added. To timely address the comments an (additional) editor has been added. Updates have been announced to the working group and no further obligations were received.

Document Quality:

This document is an informational requirements document, therefore there is of course no implementation related to this.

The document received several rounds of reviews in total of 10 different persons (incl. 4 in WGLC and 2 from people mainly working in RTCweb) leading to discussions with even more people involved. These discussions led to several additions and smaller modification to the requirements.

The document contains one normative reference to an RTCweb working group document that is as know to the shepherd is close to publication.

As there is no requirements language in this document, the section on requirements language could be removed.

The structuring of the requirements could still be improved to enhance readability. However, the technical content is well addressed.

Personnel:

Mirja K¸hlewind (mirja.kuehlewind@ikr.uni-stuttgart.de) is Docoment Shepherd and one of the rmcat working group chairs.
Spencer Dawkins  is the Responsible Area Director

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I briefly reviewed the first version of this w-g doc (-00) to be able to contribute to the discussion on the mailing list. Further I performed a detailed review during wglc (-02) and have been sending it to the mailing list. Further I reviewed the version (-04) to check if various WGLC comments from different reviewers have been addressed. Finial I reread the final (-08) to check if everything is understandable and the open issues have been well addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No. A sufficient number of reviews for the whole document have been performed addressing all kind of issues regarding the content, completeness, comprehensibility as well as the wording and terminology. Further, an additional document editor has been added to ensure that the review comments have been well addressed.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

This document is informational. I don't see any security or operational issues. In fact I don't think the security consideration section is needed here, as it currently only discusses general issues on congestion control not specific to real-time media congestion control.

The document already received two reviews from the RTCweb working group (in WGLC).

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

There are no open issues that are discussed in the working group. From my personal view some sub-bullets in the requirements seems slightly redundant but that doesn't prevent a good understanding of the document.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

Yes, the authors confirmed that no IPR exists.

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The working group as a whole agreed on this document as this is the basis for further documents.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

All fixed have been resolved.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, media type, and URI type reviews.

Does not apply.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

Yes. Normative reference to [I-D.ietf-rtcweb-overview]. As far as known by the shepherd, this document is close to publication (in WGCL?) and therefore this should not be an problem. However, alternatively the (few) needed terminology could be integrated into this document and therefore the reference could be removed.

(15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 5226).

IANA section exists but no considerations required for this document. Thus should be removed before publication.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

None.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, etc.

Does not apply to this document.

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-rmcat-cc-requirements-05, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA actions.

While it is helpful for the IANA Considerations section of the document to remain in place upon publication, if the authors prefer to remove it, IANA doesn't object.

If this assessment is not accurate, please respond as soon as possible.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Congestion Control Requirements For RMCAT) to Informational RFC


The IESG has received a request from the RTP Media Congestion Avoidance
Techniques WG (rmcat) to consider the following document:
- 'Congestion Control Requirements For RMCAT'
  as Informational RFC

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2014-08-13. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  Congestion control is needed for all data transported across the
  Internet, in order to promote fair usage and prevent congestion
  collapse.  The requirements for interactive, point-to-point real time
  multimedia, which needs low-delay, semi-reliable data delivery, are
  different from the requirements for bulk transfer like FTP or bursty
  transfers like Web pages.  Due to an increasing amount of RTP-based
  real-time media traffic on the Internet (e.g. with the introduction
  of WebRTC[I-D.ietf-rtcweb-overview]), it is especially important to
  ensure that this kind of traffic is congestion controlled.

  This document describes a set of requirements that can be used to
  evaluate other congestion control mechanisms in order to figure out
  their fitness for this purpose, and in particular to provide a set of
  possible requirements for realtime media congestion avoidance
  technique.





The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-rmcat-cc-requirements/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-rmcat-cc-requirements/ballot/


No IPR declarations have been submitted directly on this I-D.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

Informational. The document specifies requirements for real-time media congestion control and thus is informational for congestion control designers and a basis for the evaluation of these algorithms.

(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary:

The documents describes requirements for real-time media congestion control. With the standardization of TRCweb, an increasing amount of real-time media is expected in the Internet and thus it's important that this traffic is congestion controlled. Real-time media traffic has quite different requirements on congestion control as most of the rest of the Internet traffic. The requirements are listed in this document to develop and later evaluate a congestion control scheme that is more suitable to real-time media traffic than today's existing schemes.

Working Group Summary:

There was quite a lot discussion in the working group on how to define fairness (mainly in respect to evaluation criteria document). For this document the working group concluded to leave the definition of fairness open (to the evaluation criteria document). Only self-fairness was defined (as roughly equal bandwidth). Further there was a discussion on RTT-fairness. This was added as an optional requirement ("if possible").

Additionally this document address requirements to handle different RTP stream multiplexed into one connection (5-tuple) or different DSCP marking within one connection. Those points where discussed on the RTPweb as well as on the rmcat mailing list.

Document Quality:

This document is an informational requirements document, thus there are no implementations...

The document received several rounds of reviews in total of 10 different persons (incl. 4 in WGLC and 2 from people mainly working in RTCweb) leading to discussions with even more people involved. These discussions led to several additions and smaller modification to the requirements.

The document (still) contains two references to other w-g documents of RTCweb and rmcat. Potentially those references should be removed before publication by adding a brief summary of the respective content instead.

There are (in total) two 'SHOULD's in the document which both probably should be a 'should'.

Personnel:

Mirja Kühlewind (mirja.kuehlewind@ikr.uni-stuttgart.de) is Docoment Shepherd and one of the rmcat working group chairs.
Spencer Dawkins  is the Responsible Area Director

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

I briefly reviewed the first version of this w-g doc (-00) to be able to contribute to the discussion on the mailing list. Further I performed a detailed review during wglc (-02) and have been sending it to the mailing list. Further I reviewed the current version (-04) to check if various wglc comments from different reviewers have been addressed.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed? 

No. A sufficient number of reviews for the whole document have been performed addressing all kind of issues regarding the content, completeness, comprehensibility as well as the wording and terminology.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

This document is informational. I don't see an security or operational issues. In fact I don't think the security consideration section is needed here, as it currently only discusses general issues on congestion control not specific to real-time media congestion control.

The document already received two reviews from the RTCweb working group (in wglc).

(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

There are no open issues that are discussed in the working group. From my personal view some subbullets in the requirements seems slightly redundant but that doesn't prevent a good understanding of the document.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

Yes, the author confirmed that no IPR exists.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No.

(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it?

The working group as a whole agreed on this document as this is the basis for further documents.

(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

The abstract contains a reference ([I-D.ietf-rtcweb-overview]), which it shouldn't.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

Does not apply.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

Yes. Normative reference to [I-D.ietf-rtcweb-overview]. I would propose to include the needed terminology into this document and remove the reference or list it as an informative reference as this RTCweb document will probably stay a w-g document until most of the RTCweb work is completed.

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

No.

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

No.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

IANA section exists but no considerations required for this document. Thus should be removed before publication.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

None.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

Does not apply to this document.