Re: [dmarc-ietf] Are Evaluators motivated to switch to Tree Walk?

[Alessandro Vesely <[e-mail]>]

On Sun 19/Jun/2022 18:08:57 +0200 John R Levine wrote:
>>> That seems like a pessimal way to make things interoperate: use one of
>>> an unknown set of algorithms ...
>> 
>> Given that we're already working in an environment where it's unlikely that
>> everyone's working from a common version of the PSL, I don't think this is
>> such a scary idea.
> 
> But one of the points of the tree walk is that for the first time it gives us a 
> well-defined algorithm that everyone can use to get the same answer.


Getting the right answer is essential, of course.  However, DMARC doesn't 
provide for interoperation among different evaluators.  That everyone gets 
exactly the same answer is not so crucial.


> I realize that the PSL works OK, mostly, we think, give or take its daily 
> updates and no agreement about whether you use the whole thing or just the 
> nominally more official first part.


The tree walk is going to be better than the PSL when all the critical nodes 
will have been flagged adequately.  Currently, there are uncertain areas using 
either algorithm.


> I don't see why we would want to make things worse.


A simple reason is backward compatibility.  But, from an editorial POV, 
specifying both brings an occasion to highlight their differences and analyze 
why one is better than the other under what respects.


Best
Ale
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