Subject: CAP - UPN question

From: Doug Royer <[email-masked]>
Date: Fri, 18 Aug 2000 09:33:32 -0700

A question for Paul Hill.

In the Definitions section is:

"User Principal Name (UPN)"
An identifier that denotes a unique CU. A UPN is an RFC 822 ...
 .... A CU's UPN MUST never be deliverable to a different person. ...

What about if someone does a READ of a VCAR. Should the
CS filter out all other UPN's from the reply?

-Doug

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From: "Paul B. Hill" <[email-masked]>
Date: Fri, 18 Aug 2000 14:59:19 -0400

>CS filter out all other UPN's from the reply?

IMHO, no. If you are reading a VCAR it might be because you are trying to 
determine who is on the VCAR.

The intent of the phrase, "A CU's UPN MUST never be deliverable to a 
different person.", is to cover the situation where a person's UPN is not 
the same as their email address. Let's take the following example. Suppose 
that we have a person that has an email address of [email-masked]. But the 
CS administrator has assigned BOB a UPN of [email-masked].

This might cause some confusion for people that interact with Bob. They 
might know him as [email-masked] and [email-masked] in two different 
contexts, they might not even realize that they map to the same person. But 
if someone sends mail to [email-masked] it shouldgo to either Bob, or bounce.

Mail sent to [email-masked] must not be delivered to someone else. (Ignore 
the issue of bounces going to postmaster.)

Another way of saying this is, if a domain has a disjoint namespace between 
the CS UPN's and the email identifiers used in the same DNS domain, then no 
collisions should occur; alternatively a domain may choose to implement a 
single namespace that unifies their CS UPN's and their email identifiers.

Does this help, or did I just cause even more confusion?

Paul

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From: Doug Royer <[email-masked]>
Date: Fri, 18 Aug 2000 12:20:27 -0700

"Paul B. Hill" wrote:
> ....
> Another way of saying this is, if a domain has a disjoint namespace
> between the CS UPN's and the email identifiers used in the same DN
> domain, then no collisions should occur; alternatively a domain may
> choose to implement a single namespace that unifies their CS UPN's
> and their email identifiers.
> 

Helps - I'll add/tweak the text to reflect this.

Thanks!
-Doug