Subject: RE: Node Req: Issue31: DHCPv6 text (ignore previous mails)

From: [email-masked]
Date: Thu, 4 Dec 2003 14:24:18 +0200

Hi Tim,

> I guess it would be good to get Ralph's input here.
> 
> Clearly clients may implement a subset, and if we consider that for this
> document we can either
> 
> a) add references to stateless DHCPv6, but this is not finished so that 
>    is not ideal
> 
> b) use language that emphasises whether the client implements stateful
>    address configuration and/or other configuration options (and for now
>    we assume that these are the two possible subsets of functionality)
> 
> Running with b) seems safer at this stage - it would add a bit of wordage 
> but avoid the possible hold-up that Thomas hints at?

I'd prefer adding an informative reference to stateless DHCPv6, and mention
its relation to 'normal' DHCP.  

Ralph, any suggested text?

John

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From: Ralph Droms <[email-masked]>
Date: Thu, 04 Dec 2003 15:51:30 -0500

Here are some comments and suggested text for 
draft-ietf-ipv6-node-requirements-06.txt:

It would be good to use either DHCP or DHCPv6 (but not both) consistently 
throughout the doc.

5.3.1 Managed Address Configuration

The first two paragraphs are sort of redundant relative to the second 
paragraph in section 4.5.5.  I suggest that the union of the information in 
the two sources be put into section 4.5.5, and the first two paragraphs of 
5.3.1 be deleted.

I suggest the following text for 5.3.1:

    Those IPv6 Nodes that use DHCP for address assignment initiate DHCP
    to obtain IPv6 addresses and other configuration information upon
    receipt of a Router Advertisement with the 'M' flag set, as
    described in section 5.5.3 of RFC 2462.  In addition, in the
    absence of a router, those IPv6 Nodes that use DHCP for address
    assignment MUST initiate DHCP to obtain IPv6 addresses and other
    configuration information, as described in section 5.5.2 of RFC
    2462.  Those IPv6 nodes that do not use DHCP for address assignment
    can ignore the 'M' flag in Router Advertisements.

5.3.2 Other configuration information

I suggest changing the title of this section because the development of 
DHCP has moved toward using a DHCP in a way that is typically known as 
"stateless".  I recognize the potential confusion with RFC 2462, in which 
"stateful" is pretty deeply embedded.

I think the first paragraph of 5.3.2 is redundant and should be merged in 
with the text in 4.5.5.

I suggest the following text for 5.3.2

    Those IPv6 Nodes that use DHCP to obtain other configuration
    information initiate DHCP for other configuration information upon
    receipt of a Router Advertisement with the 'O' flag set, as
    described in section 5.5.3 of RFC 2462.  Those IPv6 nodes that do
    not use DHCP for other configuration information can ignore the 'O'
    flag in Router Advertisements.

    An IPv6 Node can use the subset of DHCP described in [DHCPv6-SL]
    to obtain other configuration information.

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From: Tim Chown <[email-masked]>
Date: Mon, 8 Dec 2003 00:34:25 +0000

Ralph,

This simplification and use of language looks good.

As an aside:

There is a minor discrepancy in text between 2461 and 2462 that could
perhaps be clarified in the -bis work for those texts.   This is regarding 
the M flag referring to addresses and other options, or just addresses.
Three parts of the texts have different nuances:

a) 2461 section 4.2 says M flag means hosts use the stateful protocol
   for address assigment, and O flag means hosts used the stateful protocol
   for other (non-address) information.

b) Then in 2462 it says in Section 4 (p.9) and Section 5.2 (p.11) again
   that a "managed address configuration" flag indicates whether hosts should 
   use stateful autoconfiguration to obtain addresses and an "other stateful
   configuration" flag indicates whether hosts should use stateful 
   autoconfiguration to obtain additional information (excluding addresses).

c) But then in 5.5.3 of 2462 the RA processing text states what I expect
   most (all?) implementations actually do:  "If the value of ManagedFlag 
   changes from FALSE to TRUE ...  the host should invoke the stateful address 
   autoconfiguration protocol, requesting both address information and other 
   information." (i.e. for both information)

So the question is should the wording of (a) and (b) be changed to reflect
the processing text of (c)?  On their own, (a) and (b) suggest that to get
the behaviour of (c) *both* the M and O bits should be set, but (c) states
that only the M bit need be set for full stateful autoconfiguration. 

Tim

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From: "Christian Strauf (JOIN)" <[email-masked]>
Date: Mon, 08 Dec 2003 10:41:16 +0100

Hi Tim, hi Ralph,

I also completely agree with Ralphs wording. Tim: regarding the issue

> that only the M bit need be set for full stateful autoconfiguration. 
In my eyes, (a) and (b) should be reworked to reflect the behaviour
described in (c). If the M flag is set, deciding which additional
information is to be sent or if it is sent at all is a matter of the
DHCPv6 server's configuration.

Christian