Re: [Lsr] New draft on Flex-Algorithm Bandwidth Constraints

Robert Raszuk <robert@raszuk.net> Sat, 27 February 2021 12:24 UTC

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From: Robert Raszuk <robert@raszuk.net>
Date: Sat, 27 Feb 2021 13:24:19 +0100
Message-ID: <CAOj+MMHKazMG3wnUA+Kd2wg2hfr01CdF5w5YYKdFaHU4_V+0SA@mail.gmail.com>
To: William Britto A J <bwilliam=40juniper.net@dmarc.ietf.org>
Cc: "lsr@ietf.org" <lsr@ietf.org>, Rajesh M <mrajesh@juniper.net>, Shraddha Hegde <shraddha@juniper.net>, "DECRAENE Bruno IMT/OLN" <bruno.decraene@orange.com>
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Subject: Re: [Lsr] New draft on Flex-Algorithm Bandwidth Constraints
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Hi William & co-authors,

I read the draft and have two basic questions.

1.
Both bw & delay can be used as defined in the draft to construct new
forwarding topologies. But how practical such topologies would be in the
real life when 40GB links may be heavily occupied with bursty traffic and
10G links can sit idle ? I suppose you are trying to address the case where
say 12 gbps holographic stream needs to be sent across a network.. But then
I don't think if sending it in a single flow instead of spreading into many
sub-flows and use as much as possible ecmp would not be a better option.

2.
Likewise how good is my accumulated link delay value if in between there
are deep buffer network elements and say egress queuing to each link (which
max is unaccounted for in your draft) can significantly alter the end to
end delay ? Have you consider to add MAX_EGRESS_QUEUE_DELAY on a per link
basis (still as static value).  So if some traffic is delay sensitive we
will have a much better accuracy not to get into a trap of queuing related
delays.

Thx a lot,
Robert.


On Fri, Feb 26, 2021 at 8:37 AM William Britto A J <bwilliam=
40juniper.net@dmarc.ietf.org> wrote:

> All,
>
>
>
> We would like to draw your attention to a new ID:
> https://datatracker.ietf.org/doc/html/draft-hegde-lsr-flex-algo-bw-con-00
>
>
>
> The draft talks about introducing link bandwidth related constraints in
> Flex-Algorithm which can be used to define a Flex-Algorithm based on
> bandwidth based metric.
>
>
>
> Please review. Any questions and comments are welcome.
>
>
>
> Thanks,
>
> William
>
>
>
>
>
> *From: *internet-drafts@ietf.org <internet-drafts@ietf.org>
> *Date: *Monday, 22 February 2021 at 10:56 PM
> *To: *Bruno Decraene <bruno.decraene@orange.com>om>, Rajesh M <
> mrajesh@juniper.net>gt;, Rajesh M <mrajesh@juniper.net>et>, Shraddha Hegde <
> shraddha@juniper.net>gt;, William Britto A J <bwilliam@juniper.net>et>, William
> Britto A J <bwilliam@juniper.net>
> *Subject: *New Version Notification for
> draft-hegde-lsr-flex-algo-bw-con-00.txt
>
> [External Email. Be cautious of content]
>
>
> A new version of I-D, draft-hegde-lsr-flex-algo-bw-con-00.txt
> has been successfully submitted by Shraddha Hegde and posted to the
> IETF repository.
>
> Name:           draft-hegde-lsr-flex-algo-bw-con
> Revision:       00
> Title:          Flexible Algorithms Bandwidth Constraints
> Document date:  2021-02-22
> Group:          Individual Submission
> Pages:          21
> URL:
> https://urldefense.com/v3/__https://www.ietf.org/archive/id/draft-hegde-lsr-flex-algo-bw-con-00.txt__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD3v6TruoA$
> <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-hegde-lsr-flex-algo-bw-con-00.txt__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD3v6TruoA$>
> Status:
> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-hegde-lsr-flex-algo-bw-con/__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD1VexjHPQ$
> <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-hegde-lsr-flex-algo-bw-con/__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD1VexjHPQ$>
> Htmlized:
> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/html/draft-hegde-lsr-flex-algo-bw-con__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD3X5nPQbA$
> <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-hegde-lsr-flex-algo-bw-con__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD3X5nPQbA$>
> Htmlized:
> https://urldefense.com/v3/__https://tools.ietf.org/html/draft-hegde-lsr-flex-algo-bw-con-00__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD2aqSYcuQ$
> <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-hegde-lsr-flex-algo-bw-con-00__;!!NEt6yMaO-gk!QGg36p91zPfVMznYY91xs-zx70Qp5BE1nJx-Thnl14sTCkvwgOjEzjGBtD2aqSYcuQ$>
>
>
> Abstract:
>    Many networks configure the link metric relative to the link
>    capacity.  High bandwidth traffic gets routed as per the link
>    capacity.  Flexible algorithms provides mechanisms to create
>    constraint based paths in IGP.  This draft documents a set of
>    bandwidth related constraints to be used in Flexible Algorithms.
>
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
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