attribute retrieval protocol

[Argyn <argyn@cox.net>]

This is related to remore PDP problem. If there's not enough attributes in  
the reques, how does PDP finds them?

There's no XML schema to request an attribute. According to spec context  
handler find attributes. How is this going to work in the netwrok?

I thought if there wer XML schema to request attribute, then this could  
work better in Web environment. A client sends XACML Request to PDP  
server. Currently, it expects to get XACML Response with a decision.
  What if we change Response contract, making it return a request for  
additional information. there'll be XACML scehma for a responce with such  
a request.

1. Request goes to PDP
2. Response from PDP contains a request for additional information. It  
also has a sessionId.
3. new Request with additional info goes to PDP, it contains sessionId  
 from prev step, so PDP knows that this is for an existing request.
4. Response from PDP contains a decision.

Basically, this is alomost the same how it works now, the difference is  
that request to ContextHandler for other attributes has its own XML schema.

thanks,
Argyn