Re: [Int-dir] Intdir telechat review of draft-ietf-tvr-use-cases-05

[Pascal Thubert <[e-mail]>]

It’s up to you Yingzhen.

Like I said my comments are a matter of taste and the draft can progress without answering my questions below.

I’d say that TVR is tractable when the impact of the rerouting is predictable, and otherwise subject to consequences on the rerouted as well as the non rerouted flows on the impacted links.

All the best,

Pascal

Le 29 févr. 2024 à 20:17, Yingzhen Qu <[e-mail]> a écrit :



Hi Pascal,

Would you please check whether your comments have been addressed?

Thanks,

Yingzhen

On Sat, Feb 24, 2024 at 3:58 PM Yingzhen Qu <[e-mail]> wrote:

Hi Pascal,

Thanks for the review and comments. Please see my answers below.

Thanks,

Yingzhen

On Wed, Feb 21, 2024 at 8:43 AM Pascal Thubert via Datatracker <[e-mail]> wrote:

Reviewer: Pascal Thubert
Review result: Ready with Issues

I am an assigned INT directorate reviewer for draft-ietf-tvr-use-cases (05).
These comments were written primarily for the benefit of the Internet Area
Directors. Document editors and shepherd(s) should treat these comments just
like they would treat comments from any other IETF contributors and resolve
them along with any other Last Call comments that have been received. For more
details on the INT Directorate, see
https://datatracker.ietf.org/group/intdir/about/" rel="noreferrer nofollow" target="_blank">https://datatracker.ietf.org/group/intdir/about/
<https://datatracker.ietf.org/group/intdir/about/" rel="noreferrer nofollow" target="_blank">https://datatracker.ietf.org/group/intdir/about/>."

For non-INT Area document, the reviewer must give a recommendation as to how
the INT ADs are to complete the ballot on the document and the reason for that
recommendation.

I believe that the document is very well written and highly readable.

My comments may be seen as a matter of taste and ignored, or/and be considered
out of scope.

My main concern is that despite a "Routing Impacts" subsection in all main
groups of use cases, there's no text on the scope of routing impact.

- Is the impact local like FRR in which case it can be understood?
- Or is it more global in which cases the impact is harder to assess in
advance? - flows may be rerouted paths that are loaded differently from the
original, meaning that there's a measurable impact at the time of the switch,
for the better or the worse - How, when can the impact be gradual? - Is the
impact a complete reroute of the flow or a variation of the load balancing?

Background fo rthe questions: Rick and myself have a strong RAW background.
Contrary to the examples given (and the WG ovbjectives), RAW is reactive (OAM
based); but once a decision is made, it seems that the RAW methods are
applicable in certain listed use cases and may provide a smpooth solution to
the local TVR use cases.

Related comment is that the "Routing Impacts" subsections are not comparable
from one use case to the other. Again I'd have loved comparable items like the
above to be discussed so we figure if we are looking for common or separate
solutions.

[Yingzhen]: As we know, Fast Reroute (FRR) is a local mechanism designed to handle unexpected node or link failures, and there might be policies for determining which traffic should be switched to the backup path. However, this falls outside the scope of TVR's charter and this document. Scheduled maintenance, such as link shutdowns, is within scope. Ultimately, how routing protocols handle these scheduled events is up to the protocols, including deciding whether a 'one size fits all' solution is appropriate. One of the objectives of the use case document is to clarify the cases considered by TVR.

Secondary, on :
                                "To the extent that the relative mobility
                                between and among nodes in the network can be
                                understood in advance, the associated loss and
                                establishment of adjacencies can also be
                                planned for."

This is clearly discussing radios. Most radios use cases depend not only on the
relative position, but also the rest of the environment that may obstruct and /
or interfere with the signal. Suggestion:

                                "To the extent that the relative mobility
                                between and among nodes in the network and the
                                impacts of the environment on the signal
                                propagation can be understood in advance, the
                                associated loss and establishment of
                                adjacencies can also be planned for."

[Yingzhen]: thanks for the suggested text. I've published version -06 with the suggested changes.

 

Many thanks again for this document, great and informational read