Subject: Re: Francis's INput at the Design Meeting

From: Francis Dupont <[email-masked]>
Date: Wed, 20 Sep 2000 00:34:41 +0200

In your previous mail you wrote:

   I'm for keeping the DHCPv6 name.

=> the name doesn't really matter but:
 - IMHO it is important to understand DHCPv6 is more the statefull version
   of IPv6 autoconfiguration than the IPv6 version of DHCP, ie. it is
   supposed to add management to the existing stateless autoconf, not
   to do things which are exotic (for IPv6) or already done by other
   tools (like some service discovery).
 - formally the name DHCPv6 is wrong because it will apply to routers
   too (in fact, DHCPv6 is more useful for routers than for hosts because
   stateless autoconf works only for hosts). This point should be made
   clear in the new draft.

   ND Daemon is a Neighbor Discovery daemon, I suspect.

=> yes, ND is the nick name of Neighbor Discovery. Prefix discovery and
address autoconfiguration are two of the nine functions of ND.

   I think Jim feels that DHCPv6 (client side) is really part of the
   ND Daemon that handles all addressing issues (whether stateful or
   not).
   
=> the code managing the stateless autoconf must interoperate with
the DHCPv6 client. An easy way to do this is to manage both in an
user daemon.

Regards

[email-masked]

---

From: Ralph Droms <[email-masked]>
Date: Tue, 19 Sep 2000 18:12:03 -0700

>    tools (like some service discovery).

Can you tell me what you mean by "the stateful version of IPv6
autoconfiguration"?  How does that differ from what the -15 draft
of DHCPv6 does?

- Ralph

---

From: Francis Dupont <[email-masked]>
Date: Wed, 20 Sep 2000 19:41:22 +0200

autoconfiguration"?

=> according to RFC 2461 introduction:

(what is autoconfiguration)

   This document specifies the steps a host takes in deciding how to
   autoconfigure its interfaces in IP version 6. The autoconfiguration
   process includes creating a link-local address and verifying its
   uniqueness on a link, determining what information should be
   autoconfigured (addresses, other information, or both), and in the
   case of addresses, whether they should be obtained through the
   stateless mechanism, the stateful mechanism, or both.  This document
   defines the process for generating a link-local address, the process
   for generating site-local and global addresses via stateless address
   autoconfiguration, and the Duplicate Address Detection procedure. The
   details of autoconfiguration using the stateful protocol are
   specified elsewhere.

(what is the stateful autoconfiguration)

   In the stateful autoconfiguration model, hosts obtain interface
   addresses and/or configuration information and parameters from a
   server.  Servers maintain a database that keeps track of which
   addresses have been assigned to which hosts. The stateful
   autoconfiguration protocol allows hosts to obtain addresses, other
   configuration information or both from a server.  Stateless and
   stateful autoconfiguration complement each other. For example, a host
   can use stateless autoconfiguration to configure its own addresses,
   but use stateful autoconfiguration to obtain other information.
   Stateful autoconfiguration for IPv6 is the subject of future work
   [DHCPv6].

   How does that differ from what the -15 draft of DHCPv6 does?

=> my concern is about the "other informations". Some are critical
(security, DNS), some can be useful (NIS/NIS+/WINS server), some
are only ridiculous (weather schedule :-).

The current draft tries to be multi-purpose, IMHO this is a bad idea
because this makes DHCPv6 even more complex and not suitable for
a simple discovery mechanism.

Perhaps it is not the time to discuss about this (even if this issue
is a source of the incredible delay of DHCPv6) but I argue (and I'll
continue to argue) that the priority is the address configuration.

We already have the stateless autoconfiguration for years then:
 - we have the proof the discovery part is not (yet) critical
 - we have a lot of constraints on address configuration
   (ie. in some cases DHCPv6 should do the same thing than stateless
    autoconf with the "database that keeps track of which addresses
    have been assigned to which hosts" in (only) addition)

Regards