Re: [xacml] [CR] New Section 7.x: Request context. Forwarded messagefrom Seth Proctor.

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From: Seth Proctor <>
To: Anne Anderson <>
Subject: Re: [xacml] [CR] New Section 7.x: Request context
Date: Tue, 8 Oct 2002 15:53:14 -0400
> If a referenced attribute is not available in the cached list of
> attributes or among those supplied by the PEP, then a request is
> made to the PIP for a value for the referenced attribute. This
> request is implementation-dependent, and is not visible to the
> PDP. If the PIP is not able to supply a value for the attribute,
> then a result of "Indeterminate" due to "Missing attribute" is
> returned to the PDP. As I pointed out yesterday, the PDP _is not_ shielded from the implementaion dependent stuff. There is no standard that describes what a PIP is, or how a PDP talks to it in any standard way, so either the PDP is the PIP (and therefore knows all the implementation-dependent issues), or the PDP talks to a PIP, and therefore defines an implementation-dependent communication model. Either way, the PDP is not being shielded from anything. If you want to be pedantic about the PIP being a conceptually different thing, that's fine, but from an implementation and an interoperability point of view, it doesn't help anything. Also, in your last paragraph, I think it's confusing how you tried to fold in the language about short-circuit evaluation. This is a separate topic, and needs to be discusssed in greater detail in its own section. seth

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Anne H. Anderson
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