Re: Mirja Kühlewind's No Objection on draft-ietf-rtgwg-rlfa-node-protection-10: (with COMMENT)

[Pushpasis Sarkar <[e-mail]>]

Hi Mirja,

Thanks for your comments once again.. Please find some more answers inline

-Pushpasis

On Wed, Jan 18, 2017 at 9:02 PM, Mirja Kühlewind <[e-mail]>
wrote:

> Hi Pushpasis,
>
> thank for your replies. Please see below!
>
> Mirja
>
> On 18.01.2017 03:42, Pushpasis Sarkar wrote:
>
>> Hi Mirja,
>>
>> Thanks a lot for the comments. And sorry for not being able to reply
>> earlier.
>> Please find some comments  inline.
>>
>> Thanks
>> -Pushpasis
>>
>> On Mon, Jan 16, 2017 at 10:03 PM, Mirja Kuehlewind <[e-mail]
>> <mailto:[e-mail]>> wrote:
>>
>>     Mirja Kühlewind has entered the following ballot position for
>>     draft-ietf-rtgwg-rlfa-node-protection-10: No Objection
>>
>>     When responding, please keep the subject line intact and reply to all
>>     email addresses included in the To and CC lines. (Feel free to cut
>> this
>>     introductory paragraph, however.)
>>
>>
>>     Please refer to https://www.ietf.org/iesg/stat
>> ement/discuss-criteria.html
>>     <https://www.ietf.org/iesg/statement/discuss-criteria.html>
>>     for more information about IESG DISCUSS and COMMENT positions.
>>
>>
>>     The document, along with other ballot positions, can be found here:
>>     https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node-
>> protection/
>>     <https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node
>> -protection/>
>>
>>
>>
>>     ------------------------------------------------------------
>> ----------
>>     COMMENT:
>>     ------------------------------------------------------------
>> ----------
>>
>>     Overall comment: This reads rather like an informational rfc; however
>>     given that rfc7490 is standards track, I guess that's fine.
>>
>>     More specific comments:
>>     - More abbreviations could be spelled out to make it easier to read.
>>
>> [Pushpasis] I will try to add as many as I can in the next version :)
>>
>>     - Not sure what section 3 tells me; but I'm also not an expert.
>>
>> [Pushpasis] Section 3 is about a using the same solution proposed to find
>> a
>> node-protected R-LFA path by running a forward-SPF on the PQ node(s) to
>> select parameters of the same paths discovered, so that the computing
>> router
>> on discovering multiple R-LFA backup paths to a single destination can run
>> some backup-path-selection policies on the same path parameters collected
>> (while doing computing F-SPF) to select one or more best suited R-LFA
>> backup
>> paths for the destination. Hope it explains :) You may also want to refer
>> to
>> RFC7916 for more explanation.
>>
>
> Still not clear to me. Anyway I'm not an expert and maybe I'm missing
> something. Or let me ask the questions differently: What does this part add
> to the rest of the doc and why is this a separate section?

[Pushpasis] The solution proposed to solve the first problem in section 2
(i.e. ensuring node-protection with R-LFA) can also be extended to solve
another problem (i.e. collecting parameters used by
backup-selection-algorithm RFC7916 wrt to R-LFA backup paths (this is more
detailed in section 6.2.5.4 of RFC7916). Since the same solution in a
extended form also solved a separate but related problem, this was curved
out as separate section. In summary this document proposes to two separate
but related problems and hence two different sections..  Hope I could
answer this satisfactorily this time.. :)


>
>
>>     - Also section 3: "As already specified in Section 2.3.4 to limit the
>>     computational
>>        overhead of the proposed approach, forward SPF computations MUST be
>>        run on a selected subset from the entire set of PQ-nodes computed
>> in
>>        the network, with a finite limit on the number of PQ-nodes in the
>>        subset."
>>        I guess you don't need the upper case MUST here.
>>
>> [Pushpasis] Actually this was suggested to be exactly a MUST in WG
>> discussions on the WG mail
>>
>
> My point was, given this is a MUST in section 2.3.4 and this sentence
> starts with "As already specified in Section 2.3.4" it does have to be an
> upper case MUST here again (because it's correctly normatively specified in
> section 2.3.4). However not a big issue.

[Pushpasis] Got it. Will do so..


>
>
>
>>     - Also then in section 2.3.4: "To limit the computational overhead of
>> the
>>     approach proposed, this
>>        document proposes that implementations MUST choose a subset from
>> the
>>        entire set of PQ-nodes computed in the network, with a finite limit
>>        on the number of PQ-nodes in the subset."
>>        Saying "this doc recommends" and "MUST" in the same sentence seem
>>     inaccurate.
>>
>> [Pushpasis] Should I replace 'recommends' with 'specifies' then?
>>
>>     - And also section 2.3.4: Could you maybe suggest or discuss an
>>     appropriate default value?
>>
>> [Pushpasis] I have myself implemented it for Juniper and the default
>> value as
>> 16. I can specify the same as a suggested default. But I am not sure it
>> will
>> be raise any concern in the WG or not. If you suggest, I can go ahead and
>> put
>> this in the next version.
>>
>
> If you think this could raise any concerns in the wg, you should go back
> to the wg mailing list and ask for feedback/confirmation.
>
[Pushpasis] I dont think it will raise a concern. Just wanted to avoid
unwarranted discussion.. :) Anyways I will provide some text in the next
version and ask WG to let know any comments or opinion.

Thanks and Regards,
-Pushpasis


>
>
>
>
>> Thanks once again
>> -Pushpasis
>>
>>