Subject: RE: IA identifiers

From: Bernie Volz <[email-masked]>
Date: Thu, 1 Feb 2001 18:17:58 -0500

Wasn't Ted going to write up something about a technique to generate unique
ids? It was to use communication with the server to have the server provide
a DUID to the client (if the client didn't have another mechanism for
providing one). [Sorry to put you on the spot Ted.]

- Bernie

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 6:10 PM
To: DHCPv6 discussion list
Subject: Re: IA identifiers

>At the WG meeting in San Diego, we discussed how DHCP clients and servers 
>can identify Identity Associations (IAs).  The two proposals on the table 
>are to use a DHCP Unique Identifier (DUID) or to use the interface 
>identifier portion of a host's link-local  address along with a prefix from

>the link to which the host is attached.
>
>In short summary, the difference between the two schemes is the assumptions

>about the global identity an IA.  If we use a DUID to identify an IA, DHCP 
>servers can assume that an IA with the same DUID that arrives from a new 
>link (from a different link than it was originally associated with) is 
>really the same IA, and the servers can take action on that assumption.  If

>we use <interface identifier, prefix>, a roaming IA cannot be identified.
>
>We have not yet fully defined how hosts might be able to generate a DUID 
>that can be guaranteed to be unique among all DHCP clients.  We have 
>operational experience with DHCPv4 that assuming MAC addresses (e.g., from 
>a NIC) are unique is a bad assumption, and that identifier clashes among 
>DHCP clients in DHCPv4 has been a problem.

	sorry if I don't follow past discussions well.
	if there's no concrete algorithm for generating DUID, i think the
	discussions will not be useful...  i'd suggest either
	(1) define DUID generation algorithm and then discuss between
	    DUID and interface ID,
	(2) use inteface ID

	(i believe it so hard to define DUID with total global uniqueness -
	it is almost impossible, I think)

itojun