Subject: Re: [XCON] Policies in the data model

From: Gonzalo Camarillo <[email-masked]>
Date: Thu, 01 Feb 2007 15:23:48 +0200

Hi,

> But, adopting a generic model for the entire schema without
> specifying the applicability can be quite disastrous for inter-op.

As far as I know, nobody has proposed not to specify the applicability
of the model.

> How would this model solve some of the following:
> 
> - What if one feature maps to one or more XML sub-elements?

one would need to define access rights for all the sub-elements.

> - What if one or more features map to the same XML sub-elements and 
> there are differing restrictions to those?

the model covers that, since different users or groups can have
different access rights.

> 
> - What if one feature maps to a certain sub-element of the data model
>  and also to one or more commands (over the control protocol)?

I will start a new email thread on this issue because it is the old
discussion between having syntactic or semantic approaches. It is
essential that we decide which model to use in order to make progress.

Cheers,

Gonzalo

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---

From: "Mary Barnes" <[email-masked]>
Date: Mon, 26 Feb 2007 15:00:09 -0600

I realize this thread spawned into the semantic vs syntactic, but wanted
to explicitly respond that
I think the proposal for handling the role concept with more general
groups is okay.   We did attempt to define the role concept in the CCMP
document, but I can see the value in having this be less explicit and
agree that it can be accomplished by assigning rights to groups.  

Mary

-----Original Message-----
From: Gonzalo Camarillo [mailto:[email-masked]] 
Sent: Thursday, January 25, 2007 12:00 AM
To: XCON
Cc: [email-masked]; [email-masked]
Subject: [XCON] Policies in the data model

Hi,

we are preparing a new revision of the data model draft and would like
to discuss how to encode policies. The current revision of the draft
uses the concept of roles, which are ordered by their predefined
priority. Each element in the data model have a read-only and a
read-write attributes that specify which is the minimum priority (i.e.,
role) a user needs to read or modify, respectively, the contents of the
element.

We believe that the roles are not defined clearly enough in the draft
and that we need a more flexible way to convey policies in conference
documents.

Our proposal would be to remove the concept of ordered roles and use
unordered groups instead. It would be possible, then, to assign
different rights to different groups.

Another thing we would like to have is documents whose policies are easy
to read (and understand) by humans. Therefore, we would like to be able
to assign a certain policy to the main elements of the data model (i.e.,
the elements directly under the <conference-info> element) and only be
able to make it stricter (i.e., not to relax it) for their child
elements. This way, by simply checking the main elements, it will be
easy to understand whether or not the policy in the document meets the
policy requirements of the conference's administrator.

The resulting XML format would be something like this:

<main-element>
     <access type="read-write">
         <group>2</group>
         <group>3</group>
         <user>bob</user>
     </access>
     <sub-element-1>
         <access-restriction type="read-write">
             <group>3</group>
         </access-restriction>

         [contents of sub-element-1]

     </sub-element-1>
     <sub-element-2>
         <access-restriction type="read-write">
             <user>bob</user>
         </access-restriction>

         [contents of sub-element-2]

     </sub-element-2>
     <sub-element-3>

         [contents of sub-element-3]

     </sub-element-3>

</main-element>

In the example above, the contents of <sub-element-1> can be modified by
users in group 2 and Bob, the contents of <sub-element-2> can be
modified by users in groups 2 and 3, and the contents of <sub-element-3>
can be modified by users in groups 2 and 3, and Bob.

Comments?

Cheers,

Gonzalo