Re: [xacml] Draft BTG Profile

[David Chadwick <d.w.chadwick@kent.ac.uk>]

Hi Ludwig

On 26/11/2010 08:53, Ludwig Seitz wrote:
> On Thu, 2010-11-25 at 17:57 +0000, David Chadwick wrote:
>> I dont see the difference between standardising a status code in a
>> profile and standardising an Advice in a profile, except for one thing
>>
>
> There is another:
>
> To standardize an Advice Id you don't need to change the core XACML
> standard. To standardize a new status code you need to change the
> standard.


This is because the full list of codes are listed in Section B.9 (or 
B.8), yes?

But what is the standard defined behaviour for a PEP that receives an 
unknown status code? Is this documented anywhere? Probably not. Will 
they crash? Or will they ignore it? Most likely the latter.

So if a profile defines a new status code, whilst from a pure-ist point 
of view this should be in the base standard and not in a profile, 
because the standard does not allow extensibility of this feature, in 
practical terms it wont actually cause any problems to implementations 
will it?

I can accept that Advice is the Correct thing to do for v3, but what is 
the correct solution for v2?

regards

David

>
>> Advice is not available to XACMLv2 implementations
>
> Since your approach necessitates a change in core standard, backwards
> compatibility is gone either way, so I don't see a big drawback with
> using v3 specific stuff (and not changing the core v3 standard).
>
> /Ludwig
>

-- 

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