Re: [mpls] Warren Kumari's No Objection on draft-ietf-mpls-spring-entropy-label-11: (with COMMENT)

[Warren Kumari <[e-mail]>]

On Thu, Jul 5, 2018 at 7:09 PM <[e-mail]> wrote:
>
> I have added the following text:
>
> “There may also be a case where a router has a fast switching path (handled by an ASIC or network processor) and a slow switching path (handled by a CPU) with a different ERLD for each switching path. Again, for simplicity reasons, an implementation MAY use the minimum ERLD as the ERLD value for the system.”
>
>
>
> I have also highlighted the drawback as per Joe’s comment:
>
> “The drawback of using a single ERLD for a system lower than the capability of one or more specific component is that it may increase the number of ELI/ELs inserted. This leads to an increase of the label stack size and may have an impact on the capability of the ingress node to push this label stack.”
>
>

Awesome, thank you - nicely worded, and works for me.
W

>
>
>
> From: Warren Kumari [mailto:[e-mail]]
> Sent: Thursday, July 05, 2018 17:08
> To: LITKOWSKI Stephane OBS/OINIS
> Cc: The IESG; [e-mail]; [e-mail]; BRUNGARD, DEBORAH A; [e-mail]; Loa Andersson; Joe Clarke
> Subject: Re: Warren Kumari's No Objection on draft-ietf-mpls-spring-entropy-label-11: (with COMMENT)
>
>
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>
>
>
>
> On Thu, Jul 5, 2018 at 7:43 AM <[e-mail]> wrote:
>
> Thanks Warren,
>
> I agree with your comments and I will address them in the next revision.
>
>
>
> Thanks!
>
>
>
>
>
> You are right (at least from a theoretical point of view) about fast path vs slow path for ERLD. I think for this kind of switching implementation, we have several options: advertising the fast path ERLD (slow path will never be triggered), advertising the slow path ERLD (there is a possibility that slow path will be triggered for each packet), let this configurable by the user. I do not think that this fast path/slow path implementation is still popular at least for the SP router market.
>
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> I'm fine with whatever you select, I just wanted it to be considered.
>
> W
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>
> -----Original Message-----
> From: Warren Kumari [mailto:[e-mail]]
> Sent: Wednesday, July 04, 2018 20:04
> To: The IESG
> Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]
> Subject: Warren Kumari's No Objection on draft-ietf-mpls-spring-entropy-label-11: (with COMMENT)
>
> Warren Kumari has entered the following ballot position for
> draft-ietf-mpls-spring-entropy-label-11: No Objection
>
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> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
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>
>
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-mpls-spring-entropy-label/
>
>
>
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
>
> Thank you for writing this - it provides useful functionality.
>
> Please see Joe Clarke's OpsDir review here:
> https://datatracker.ietf.org/doc/review-ietf-mpls-spring-entropy-label-11-opsdir-lc-clarke-2018-06-25/
>  - it mirrors comments made by a number of ADs, and also contains a significnat
> number of nits (which would make the document better / more readable).
>
> I had a question:
> Section 4.  Entropy Readable Label Depth
> " The Entropy Readable Label Depth (ERLD) is defined as the number of
>    labels a router can both:
>    a.  Read in an MPLS packet received on its incoming interface(s)
>        (starting from the top of the stack).
>    b.  Use in its load-balancing function."
> ...
> "In a distributed switching architecture, each linecard may have a different
> capability in terms of ERLD."
>
> In many cases, a device may have a different readable label depth in hardware /
> fastpath than it does by punting the packet to the CPU / control plane. Perhaps
> the ERLD should be defined as 'Use in its load-balancing function in the
> dataplace / fast-path" (or something, this will need some wording).
>
> I'd also like to say that I like Section 10 (Options considered) - sections
> like this make a document much more satisfying (otherwise one has niggling
> questions like "What didn't they do single ELs at the bottom of the stack?!") -
> thank you for including it.
>
> I also have some nits:
> Section 1.  Introduction
> "The hashing technique is required to perfom a per-flow load-balancing and thus
> prevent packet disordering. " 1: Perform is a type 2: While 'disordering'
> explains it well, 'reordering' is a much more common term, and will (I think)
> cause less confusion.
>
> "The MPLS architecture brings some challenges on the load-balancing as an LSR
> (Label Switch Router) should be able to look at header fields that are beyond
> the MPLS label stack." "on the load-balancing" doesn't really parse. Perhaps:
> "... brings some load-balancing challenges, as..."?
>
> Section 2.  Abbreviations and Terminology
> SRGB is not defined on first use, nor it is in the Terminology section. Also,
> sorting this alphabetically would be appreciated.
>
>
>
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> --
>
> I don't think the execution is relevant when it was obviously a bad idea in the first place.
> This is like putting rabid weasels in your pants, and later expressing regret at having chosen those particular rabid weasels and that pair of pants.
>    ---maf
>
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-- 
I don't think the execution is relevant when it was obviously a bad
idea in the first place.
This is like putting rabid weasels in your pants, and later expressing
regret at having chosen those particular rabid weasels and that pair
of pants.
   ---maf