In ol’ good RSVP-TE days we already used “severity/relevance indicator” to 
decide whether changes in link  attributes (BW/etc) are significant enough and 
should be propagated in into TED and trigger re-optimization/rerouting, this is 
no different,  define your threshold for a trigger.
Note - flex-also requires contiguous topology to work, self isolation as the 
result of (dynamic) topology re-computation would not be a great thing.

Cheers,
Jeff
On Mar 1, 2021, 12:48 PM -0800, Tony Li <[email protected]>, wrote:
>
> Robert,
>
> > Constructing arbitrary topologies with bw constrain is useful work. For 
> > example I want to create a topology without links of the capacity less then 
> > 1 Gbps. All cool. Of course if I have a case where two nodes have 10 L3 
> > 1Gbps links nicely doing ECMP I will not include those which may be a 
> > problem.
>
>
> I agree that it may be a problem. Maybe it’s not the right tool for the job 
> at hand. That doesn’t make it a bad tool, just the wrong one. I try not to 
> turn screws with a hammer. And I try not to drive nails with a screwdriver.
>
> I will happily stipulate that we need more tools and that these are not 
> enough. We should not reject a tool simply because it doesn’t solve all 
> problems. Let’s work towards the right set of tools. Linear algebra tells us 
> that we want an orthogonal set of basis vectors. What are they? Adding them 
> one at a time is not horrible progress.
>
>
> > However my observation is precisely related to your last sentence.
> >
> > Is this extension to be used with static or dynamic data ? If static all 
> > fine. But as William replied to me earlier link delay may be dynamically 
> > computed and may include queue wait time. That to me means something much 
> > different if Flex-Algo topologies will become dynamically adjustable. And I 
> > am not saying this is not great idea .. My interest here is just to 
> > understand the current scope.
>
>
> Link delay was dynamic before this draft. As William mentioned, TWAMP can 
> already be used to provide a dynamic measurement of link delay. That, coupled 
> with the link delay metric already gave us dynamic path computation 
> requirements and the possibilities of oscillation and instability. We have 
> chosen to charge ahead, without addressing those concerns already.
>
> Regards,
> Tony
>
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