Re: [Detnet] New Version Notification for draft-liu-detnet-large-scale-requirements-03.txt

[Lou Berger <[e-mail]>]

Hi Peng,


Thank you for the update.  I think the clarifications are quite 
helpful.  I still have a few comments:


- I remain a bit uncomfortable the use of relative measures as a means 
to define "large-scale" - e.g, "The link delay between network nodes is 
larger..." - I think this is largely answered by section where specific 
technical requirements are defined.  I think it would be best if the 
description in the introduction (more) closely aligned with the 
requirement areas/topics called out in that section (4).


- A more minor comment - While the reference to "Local area network" may 
be applicable to TSN, I think the current text mistakenly reads as if 
current DetNet only to "Local area network".


- You include high speed links as part of what what defines a 
"Large-scale" DetNet.  My understanding is that any rate link is 
supported via current DetNet definitions.  I do agree that number of 
flows can be used to identify a "large-scale" DetNet (independent of 
link speeds).


- Similarly, I don't understand how asymmetric links are new to the 
large-scale problem, e.g., consider the RAW use case.


I suspect there will be more refinement in the document besides the 
points above once this document is accepted as a WG document,but do 
think the above should be clarified before WG adoption so that the scope 
of the work is clear to all.


Thank you,

Lou


On 10/4/2022 6:31 AM, Peng Liu wrote:
> Hi Lou,
>
> Thanks. According to your suggestion, we modified the text as follows, 
> which have the definition and the key attributes of large-scale 
> deterministic network, and each requirements proposed in Section 4 
> could map to the attributes directly or indirectly. We hope this could 
> work. The new version of the document and the diff could be found in 
> attachment.
>
> In this document we define a large-scale DetNet network as a network 
> that has longer transmission distance, more network devices and more 
> kinds of traffic flows than a local area network, it includes one or 
> more of the following key attributes:
>
>    * There are many types of network nodes which may introduce 
> disparate local time variation and buffering capabilities.
>    * The link delay between network nodes is larger, and the end to 
> end path is a combination of short and long distance hops.
>    * There are various transmission rate supported at the different 
> ports and on different network node, varying from tens of Mbps to tens 
> of Gbps or higher.
>    * The path between two neighbor nodes can be asymmetric in terms of 
> the link delay.
>    * There are a large number of flows which may travel across 
> multiple Detnet domains.
>    * The mechanisms used to ensure bounded latency (e.g. queuing 
> mechanism) may be different or have different configuration/parameter 
> in each domain.
>
> Such domains are normally within a single administrative control 
> network or multiple cooperating administrative networks within a 
> closed group of administrative control [RFC8655].  However they 
> may belong to different AS domains and be controlled by multiple 
> peering or cascaded controllers, and at the same time they may not 
> have the same time clock source. Maintaining per flow status 
> becomes impractical in the large scale network.  Aggregation and 
> disaggregation of flows take place at the boundaries of Detnet omains 
> as well as within a Detnet domain with various rules. The flow 
> identification and packet treatment should take care of one or 
> combined changes introduced by the large-scale network.
>
> Based on the defination and characteristics above, this document 
> describes requirements for large-scale deterministic networks which 
> demands the enhancement based on the existing bounded latency 
> mechanisms and the corresponding data plane to ensure the detnet 
> service for single administrative network or multiple (cooperating) 
> administrative networks that defined in the detnet charter. The 
> deterministic network for open internet is not within current scope.
>
> Regards,
> Peng
> ------------------------------------------------------------------------
> [e-mail]
>
>     *From:* Lou Berger <mailto:[e-mail]>
>     *Date:* 2022-09-30 20:32
>     *To:* Peng Liu <mailto:[e-mail]>
>     *CC:* detnet <mailto:[e-mail]>;
>     draft-liu-detnet-large-scale-requirements
>     <mailto:[e-mail]>
>     *Subject:* Re: [Detnet] New Version Notification for
>     draft-liu-detnet-large-scale-requirements-03.txt
>
>     Hi Peng,
>
>     Thank you for the response. I think your text below will help, but
>     still does not provide a precise definition of the term
>     'large-scale'. I think such a precise definition is required to
>     ensure we all understand the problem being described.
>
>
>     I suggest having text that starts with something along the lines
>     of "In this document we define a large-scale DetNet network as a
>     network that includes one or more of the following...." and then
>     expanding a bit on each of the identified key attributes.
>
>
>     Thank you!
>
>     Lou
>
>
>     On 9/27/2022 4:35 AM, Peng Liu wrote:
>>     Hi Lou,
>>
>>     Thanks for your comments. We think the large-scale deterministic
>>     network aims at the wide area network, which may also has more
>>     network devices, detnet flows and cross multi domains. Those
>>     characteristics bring more challenges to ensure the detnet service.
>>
>>     As you said, the current version is not clear about what
>>     large-scale is, and it is inaccurate to say like 'detnet is
>>     limited to a single network domain'. So we propose the
>>     modification at the last paragraphs in the Introduction Section:
>>
>>     A large-scale network usually has a longer transmission distance,
>>     more network devices and more kinds of traffic flows than a Local
>>     area network. It also has the characteristics including:
>>
>>     The link delay between network nodes is larger. The end to end
>>     path is a combination of short and long distance hops. The path
>>     between two neighbor nodes can be asymmetric in terms of the link
>>     delay. There are many types of network nodes which may introduce
>>     disparate local time variation and buffering capabilities. At the
>>     same time, there are various transmission rate supported at the
>>     different ports and on different network node, varying from tens
>>     of Mbps to tens of Gbps or higher. A large number of flows can
>>     travel across multiple Detnet domains.
>>
>>     Such domains are normally within a single administrative control
>>     network or multiple cooperating administrative networks within a
>>     closed group of administrative control [RFC8655]. However
>>     they may belong to different AS domains and be controlled by
>>     multiple peering or cascaded controllers, and at the same time
>>     they may not have the same time clock source. Maintaining
>>     per flow status becomes impractical in the large scale network.
>>     Aggregation and disaggregation of flows take place at the
>>     boundaries of Detnet domains as well as within a Detnet domain
>>     with various rules. The flow identification and packet treatment
>>     should take care of one or combined changes introduced by the
>>     large-scale network.
>>
>>
>>     This document describes requirements for large-scale
>>     deterministic networks which demands the enhancement based on the
>>     existing bounded latency mechanisms and the corresponding data
>>     plane to ensure the detnet service for single administrative
>>     network or multiple (cooperating) administrative networks that
>>     defined in the detnet charter. The deterministic network for open
>>     internet is not within current scope.
>>
>>
>>     Moreover, we will remove/refine the uncorrect description related
>>     to the multi domains in the whole text.
>>
>>     Hope that could address the issues about the 'large-scale' and
>>     'multi domain'.
>>
>>     Thanks again~
>>     Peng&co authors
>>     ------------------------------------------------------------------------
>>     [e-mail]
>>
>>         *From:* Lou Berger <mailto:[e-mail]>
>>         *Date:* 2022-09-24 00:52
>>         *To:* Peng Liu <mailto:[e-mail]>;
>>         draft-liu-detnet-large-scale-requirements
>>         <mailto:[e-mail]>
>>         *CC:* DetNet WG <mailto:[e-mail]>
>>         *Subject:* Re: [Detnet] New Version Notification for
>>         draft-liu-detnet-large-scale-requirements-03.txt
>>         Authors,
>>
>>         Thank you for this update. I have a few comments on this draft:
>>
>>         - The first question I have is what is the documents
>>         definition of "large-scale deterministic network"?
>>
>>         In the abstract you seems to imply that "large-scale"
>>         translates to "wide area":
>>            ... this document
>>            describes the technical and operational requirements when the
>>            different deterministic levels of applications co-exist
>>         and are
>>            transported over a wide area.
>>
>>         But the intro, you seem to state that "large-scale"
>>         translates to "multiple domains":
>>
>>           ... The current DetNet is limited to a
>>            single administrative domain network, and there are technical
>>            elements necessary for application to a large-scale
>>         network spanning
>>            multiple domains.
>>
>>            This document describes requirements for large-scale
>>         deterministic
>>            networks where different deterministic levels of
>>         applications co-
>>            exist and large-scale deterministic networking across multiple
>>
>>         administrative domains is possible.
>>
>>
>>         Can you clarify as well as ensure you are consistent within
>>         the document?
>>
>>
>>         FWIW, based on the later sections of the document, I suspect
>>         large-scale is used in the document to cover number of flows
>>         supported on a device and/or network, as well as longer
>>         latency of a link and/or across the detnet domain. No matter
>>         what, the document really needs to be explicit.
>>
>>
>>         - The following implies that detnet works only within a
>>         single network domain.  I think it would be good to clarify
>>         how you define "single *network* domain" in the context of
>>         this document.
>>
>>            DetNet, of which architecture is defined in RFC 8655
>>         [RFC8655],
>>            provides a capability to carry specified unicast or
>>         multicast data
>>            flows for real-time applications with extremely low data
>>         loss rates
>>            and bounded latency within a network domain.
>>
>>         Note that the charter says multiple (cooperating) networks
>>         that have different administrative control was part of the
>>         scope of initial detnet definition, and RFC  8655 defines a
>>         "DetNet domain" that is independent from areas/groups/domains
>>         of administrative control.
>>         - I think the following should be aligned with however you
>>         address the previous comment:
>>            .. As documented in RFC 8578 [RFC8578],
>>            the scope of networks addressed by the current DetNet is
>>         limited to
>>            networks that can be centrally controlled, i.e., an
>>         "enterprise" (aka
>>            "corporate") network, excluding "the open Internet,"
>>         explicitly.
>>
>>         RFC 8578 defines *example* use cases.  The appropriate
>>         reference for current DetNet *solution* scope is RFC8655 or
>>         the other solution oriented documents.  DetNet solutions are
>>         not currently limited to central control, enterprise, or
>>         corporate networks.  I do agree that the open internet is not
>>         within current scope.
>>
>>            ..The current DetNet is limited to a
>>            single administrative domain network, and there are technical
>>            elements necessary for application to a large-scale
>>         network spanning
>>            multiple domains.
>>
>>
>>         As previously noted, the current definition of DetNet is
>>         limited to networks that are under a single administrative
>>         control or within a closed group of administrative control.
>>
>>
>>         I think clarifying these points would be very helpful (and
>>         are necessary) to evaluate the remainder of the document.
>>
>>
>>
>>         Thank you,
>>
>>         Lou (as contributor)
>>
>>
>>         On 8/17/2022 4:50 AM, Peng Liu wrote:
>>>         Dear All,
>>>
>>>         We have posted the new version of
>>>         draft-liu-detnet-large-scale-requirements-03
>>>         <https://datatracker.ietf.org/doc/draft-liu-detnet-large-scale-requirements/> based
>>>         on the discussions and suggestions, and we would like to
>>>         thanks Bala'zs, Tianran and Fan for their comments. Here are
>>>         the the major changes:
>>>
>>>         1. Add some descriptions of the requirements
>>>         and clarifications not to specify solutions in Section 4.
>>>
>>>         2. Change the name of Section 5.2 as "Support Information
>>>         used by Functions ensuring Deterministic Latency".
>>>
>>>         3. Add some clarifications text in Section 5.1 and Section 5.2.
>>>
>>>         4. Add Shiyin Zhu as the co author and Lei Zhou as the
>>>         contributor.
>>>
>>>         5. Correct some formatting and spelling errors.
>>>
>>>         Most of the solution draft presented in IETF 114 reference
>>>         this document as the base requirement draft. We tried to put
>>>         the common requirements together and made some updates here.
>>>         There were around 20 people showing they had read the
>>>         document during 114 session polling. We think it is a
>>>         reasonable number to use this draft as the starting point
>>>         for the milestone of Enhanced DetNet Data Plane Requirements
>>>         document.
>>>
>>>         So we encourage the group to review the document. We plan to
>>>         ask for a call for adoption maybe next month upon chairs’
>>>         agreement.
>>>
>>>
>>>         Regards,
>>>
>>>         Peng&co authors
>>>
>>>         ------------------------------------------------------------------------
>>>         [e-mail]
>>>
>>>             *From:* internet-drafts <mailto:[e-mail]>
>>>             *Date:* 2022-08-17 15:51
>>>             *To:* Jeong-dong Ryoo <mailto:[e-mail]>; Peng Liu
>>>             <mailto:[e-mail]>; Quan Xiong
>>>             <mailto:[e-mail]>; Shiyin Zhu
>>>             <mailto:[e-mail]>; Toerless Eckert
>>>             <mailto:[e-mail]>; Yizhou Li
>>>             <mailto:[e-mail]>; zhushiyin
>>>             <mailto:[e-mail]>
>>>             *Subject:* New Version Notification for
>>>             draft-liu-detnet-large-scale-requirements-03.txt
>>>             A new version of I-D,
>>>             draft-liu-detnet-large-scale-requirements-03.txt
>>>             has been successfully submitted by Peng Liu and posted
>>>             to the
>>>             IETF repository.
>>>             Name: draft-liu-detnet-large-scale-requirements
>>>             Revision: 03
>>>             Title: Requirements for Large-Scale Deterministic Networks
>>>             Document date: 2022-08-17
>>>             Group: Individual Submission
>>>             Pages: 18
>>>             URL:
>>>             https://www.ietf.org/archive/id/draft-liu-detnet-large-scale-requirements-03.txt
>>>             Status:
>>>             https://datatracker.ietf.org/doc/draft-liu-detnet-large-scale-requirements/
>>>             Htmlized:
>>>             https://datatracker.ietf.org/doc/html/draft-liu-detnet-large-scale-requirements
>>>             Diff:
>>>             https://www.ietf.org/rfcdiff?url2=draft-liu-detnet-large-scale-requirements-03
>>>             Abstract:
>>>                Aiming at the large-scale deterministic network, this
>>>             document
>>>                describes the technical and operational requirements
>>>             when the
>>>                different deterministic levels of applications
>>>             co-exist and are
>>>                transported over a wide area.  This document also
>>>             describes the
>>>                corresponding Deterministic Networking (DetNet) data
>>>             plane
>>>                enhancement requirements.
>>>             The IETF Secretariat
>>>
>>>
>>>         _______________________________________________
>>>         detnet mailing list
>>>         [e-mail]
>>>         https://www.ietf.org/mailman/listinfo/detnet
>>