[saml-dev] What does 'AttributeNamespace' attribute mean?

Hi, all SAML developpers,

I have a question about 'AttributeNamespace' attribute in <AttributeDesingator> Element.

First, It isn't clear for me what does it means.
Does it mean the semantic definition for 'AttributeName' attribute's value?
For example, in this understanding, <AttributeDesignator AttributeNamespace="urn:ietf:rfc:2798"
AttributeName="displayName"/> means the displayName that is defined in RFC 2798 ,which is "The LDAP
inetOrgPerson Class", isn't it?

Or, does it mean the identifier specified what  the datastore should be searched in?
For example, in this understanding,  <AttributeDesignator
AttributeNamespace="ldap://ldap.nttdata.co.jp/" AttributeName="displayName"/> means a subject's
displayName which is stored in the ldap server refered to "ldap://ldap.nttdata.co.jp/", isn't it?
My understanding is the first one. Is it correct?

Second, Is there any pre-defined AttributeNamespace in the current specification?
If not, Should the semantic of AttributeNamespace be recognized between parties exchanging SAML
messages?
For example, What AttributeNamespace is used in Catalyst demonstration?

Finally, It seems for me that syntactically, <AttributeDesingator> in SAML has no relation with
<AttributeDesingator> in XACML,is it correct?

I'm glad to have any answer or comment from SAML members, though I understand most members may be
busy in preparing for Catalyst Europe.

Best Regards,
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NTT Data Corporation
Yuji Sakata
Tel: +81-3-3523-8081
E-Mail: 
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