Re: [Detnet] AD Review of draft-ietf-detnet-pof-04

[Lou Berger <[e-mail]>]

[Adding authors list to ensure they are tacking...]

Authors,

please review and respond.

Thanks,

Lou

PS Roman, Thank you for the review!

On 10/27/2023 6:43 PM, Roman Danyliw wrote:
> Feedback from idnits:
>
>    Miscellaneous warnings:
>    ----------------------------------------------------------------------------
>
>    == The document doesn't use any RFC 2119 keywords, yet seems to have RFC
>       2119 boilerplate text.
>
>> -----Original Message-----
>> From: Roman Danyliw
>> Sent: Friday, October 27, 2023 12:36 PM
>> To: [e-mail]
>> Subject: AD Review of draft-ietf-detnet-pof-04
>>
>> Hi!
>>
>> I performed an AD review on draft-ietf-detnet-pof-04 to help load balance the
>> IESG PubReq queue.  Thanks for this document.  I have the following feedback,
>> largely to improve clarity.
>>
>> Please review and respond to Henning Rogge's review at
>> https://datatracker.ietf.org/doc/review-ietf-detnet-pof-04-rtgdir-early-rogge-
>> 2023-10-23/ -- thanks Henning!
>> In particular, please review his hypothetical case of seq= 10, 5, 7 and 9 per the
>> algorithm in Section 4.3.
>>
>> ** Section 1.
>>     3 errors in-a-row is a usual error threshold and
>>     can cause the application to stop (e.g., to go to a fail-safe state)
>>
>> What is the basis for assessment that 3 is a common error threshold in
>> applications?
>>
>> ** Section 4.3. I am unsure of the framing assumed with of Detnet as it applies
>> here.  Is there obvious basic assumption around the seq_num coming from a
>> layer 2 or 3 protocol (e.g., it has one?  Which one would you choose?)  Please
>> add text similar to Section 1 of draft-ietf-detnet-mpls-over-ip-preof-07 without
>> the reference to timestamps:
>>
>>     In general, the use of PREOF functions require sequencing information
>>     to be included in the packets of a DetNet compound flow.  This can be
>>     done by adding a sequence number or time stamp as part of DetNet
>>     encapsulation.  Sequencing information is typically added once, at or
>>     close to the source.
>>
>> ** Section 4.3.
>>     Note: the difference of sequence number in consecutive packets is
>>     bounded due to the history window of the Elimination function before
>>     the POF.  Therefore "<=" can be evaluated despite of the circular
>>     sequence number space.
>>
>> As far as I can tell find, the “history window of the elimination function” is not
>> defined.
>>
>> ** Section 4.3
>>     *  "POFMaxDelay", which cannot be smaller than the delay difference
>>        of the paths used by the flow.
>>
>> Is “delay difference” than the worst-case value for the end-to-end latency?
>>
>> ** Section 4.3.  Editorial.  Per Figure 3, are “fastest” and “slowest” the right
>> adjectives to use for a time duration?
>> -- “fastest path delay” to “shortest path delay”?
>> -- “slowest path delay” to “longest path delay”?
>>
>> ** Section 4.5.  Recommend repeating what was already said in Section 4.3,
>> “Design of these parameters is out-of-scope in this document.”
>>
>> Regards,
>> Roman
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