Dear Acee, Tony,
Thanks!
Tony's explanation gives the essential use of bandwidth-metric. My previous
understanding is mainly based on the problem to be solved in another draft
https://datatracker.ietf.org/doc/draft-lp-lsr-fa-bandwidth/. Sorry to insert an
advertisement in this adoption. : )
In draft-lp, the path will be selected strictly according to the actual
bandwidth capacity of the link. The main issue is that the computation method
is not optimal, just a basic expression of this idea.
Just for the expected requirement "to select a path with the maximum link
bandwidth from the source node to the destination node", it seems that one
scheme try to satisfy most of scenarios, and the other try to satisfy 100%.
Regards
PSF
原始邮件
发件人：AceeLindem(acee)
收件人：Tony Li;彭少富10053815;
抄送人：[email protected];[email protected];[email protected];
日 期 ：2021年05月20日 18:22
主 题 ：Re: [Lsr] LSR WG Adoption Poll for "Flexible Algorithms: Bandwidth, Delay,
Metrics and Constraints" - draft-hegde-lsr-flex-algo-bw-con-02
Speaking as WG member:
I agree with Tony.
Furthermore, the extensions in the draft provide mechanisms to constraint
bandwidth beyond your concern that bandwidth be used as a cumulative metric. I
support WG adoption.
Thanks,
Acee
From: Tony Li <[email protected]> on behalf of Tony Li <[email protected]>
Date: Thursday, May 20, 2021 at 12:20 AM
To: "[email protected]" <[email protected]>
Cc: "[email protected]" <[email protected]>, Acee Lindem
<[email protected]>, "[email protected]" <[email protected]>,
"[email protected]"
<[email protected]>
Subject: Re: [Lsr] LSR WG Adoption Poll for "Flexible Algorithms: Bandwidth,
Delay, Metrics and Constraints" - draft-hegde-lsr-flex-algo-bw-con-02
Hi Peng Shaofu,
On May 19, 2021, at 6:55 PM, [email protected] wrote:
Let's go back to the bandwidth-metric related to bandwidth capability. My worry
is that bandwidth-metric (whether it is automatically calculated or manually
configured) is not cumulative in nature, which is different from IGP default
metric/TE metric/delay metric, so that SPF based on bandwidth-metric may get an
unexpected path (see the example of the original mail). Can more text be added
in the draft to describe why this can work ?
The whole point of the bandwidth metric (and indeed, of all of FlexAlgo) is to
get a different path computation result than what we might get with the
standard IGP metric. What it will do in any given topology is highly dependent
on the topology, as you’ve seen. It may or may not ‘work’ by whatever
definition you have in mind. However, what matters is what the network operator
is trying to achieve. It doesn’t have to work for every topology or every
purpose.
Tony
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