Hi Bob,
Thanks for your reply. I would say that partly because there are so many
different deployment models that MAY is precisely what is informed here.
That said, an acceptable alternative for me would be that it be SHOULD for
both DHCPv6 and SLAAC.
DHCP certainly fills a void in IPv4, i.e. the dynamic configuration of hosts
(i.e. nodes that are not routers). IMO it just isn't as necessary in IPv6 as
it is in IPv4, as there is no SLAAC-like functionality built into IPv4.
Further, it seems to me that SLAAC can be extended to do more for
configuring IPv6 hosts akin to what DHCP does for IPv4 hosts.
So, we currently have two extant standardized ways to dynamically configure
hosts in IPv6: DHCPv6 and SLAAC. I don't have any qualms about there being
two different ways to configure IPv6 hosts and understand some do. I
certainly don't have any qualms about there being more than one standardized
way to do IPv6 PD either.
Something that was ostensibly first created to address a need to dynamically
configure IPv4 hosts was further extended to allocate IPv6 prefixes to
routers. FWIW, here is a paper that examines a few different PD and CD (i.e.
certificate distribution) mechanisms: http://mobisend.org/SP1b.pdf.
I'm simply sharing my opinion, and appreciate this forum. This is my last
post on the topic, and respectfully defer to group consensus on this issue.
Thanks,
Tim
Ps 127:3-5
----- Original Message -----
From: "Bob Hinden" <[email protected]>
To: "Timothy E. Enos" <[email protected]>
Cc: "Bob Hinden" <[email protected]>; "Thomas Narten"
<[email protected]>; <[email protected]>
Sent: Friday, May 13, 2011 12:40 PM
Subject: Re: Node Requirements: Elevating DHCPv6 from MAY to SHOULD
Timothy,
On May 13, 2011, at 9:28 AM, Timothy E. Enos wrote:
Hi Thomas,
Thanks for posting this.
IMO, a SHOULD is not required in a SOHO environment (which is arguably
not a corner case for deployment). MAY works.
Just as some environments may require the use of DHCPv6, some
environments may not.
For those that require use of DHCPv6, they MAY use it.
I think at least in the SOHO context, it's really the local
administrative policies (not hard and fast technical factors) that
determine the (lack of) need for DHCPv6.
All the above said, my personal opinion is that DHCPv6 does not need to
elevated to SHOULD from MAY for the node requirements spec. If the group
decides to the contrary I can certainly accept that.
I think all we are trying to say that there are a wide range of deployment
models, that we recommend that hosts SHOULD support both. We are not
making any statement about what should be used in a particular deployment.
Or at least, that's my thinking and why I support the SHOULD. Also, why I
suggested changing the text to not talk about "operators".
Bob
My $0.02,
Tim
Ps 127:3-5
----- Original Message ----- From: "Thomas Narten" <[email protected]>
To: <[email protected]>
Sent: Friday, May 13, 2011 9:37 AM
Subject: Node Requirements: Elevating DHCPv6 from MAY to SHOULD
Per a previous thread, there are indications that the WG may now be
willing to recommend that DHCPv6 be a SHOULD for all hosts. This is
based on the following rationale:
Thomas Narten <[email protected]> writes:
I personally would support having DHCP be a SHOULD rather than a
MAY. The justification in my mind is that if you want the network
operator to have the choice of whether they want to use Stateless
addrconf OR DHCP, they only have that choice of devices widely
implement both.
This was supported by some others, particularly now that it is clear
there are more implementations of DHCPv6, e.g.:
Bob Hinden <[email protected]> writes:
While my personal view is that DHCPv6 won't be used for host
configuration in cable/DSL deployments (except for provisioning the
prefix to the home router), it appears that DHCPv6 is being widely
implemented in host OS's because it is needed some environments.
There are enough variations in deployment models that a host
developer will need to support both.
Based on this, I think a SHOULD is OK.
Let me propose the following change be made to the node requirements
document:
OLD/Current:
DHCP can be used to obtain and configure addresses. In general, a
network may provide for the configuration of addresses through Router
Advertisements, DHCP or both. At the present time, the configuration
of addresses via stateless autoconfiguration is more widely
implemented in hosts than address configuration via DHCP. However,
some environments may require the use of DHCP and may not support the
configuration of addresses via RAs. Implementations should be aware
of what operating environment their devices will be deployed. Hosts
MAY implement address configuration via DHCP.
New:
<t> DHCPv6 <xref target='RFC3315' /> can be used to obtain and
configure addresses. In general, a network may provide for the
configuration of addresses through Router Advertisements,
DHCPv6 or both. Some operators have indicated that they do
not intend to support stateless address autoconfiguration on
their networks and will require all address assignments be
made through DHCPv6. On such networks, devices that support
only stateless address autoconfiguration will be unable to
automatically configure addresses. Consequently all hosts
SHOULD implement address configuration via DHCP.</t>
Is this acceptable?
Please respond yes or no. Given the WG's previous hesitation to having
DHCPv6 be a SHOULD, it is important that we get a clear indication of
whether or not the WG supports this change.
Thomas
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