Subject: [dhcwg] 答复: Re: What about using a single dhcpv6 server for dual-stack hosts to get ipv6/ipv4 settings?

From: [email-masked]
Date: Wed, 2 Mar 2011 10:49:29 +0800

On Feb 14, 2011, at 4:43 PM, <[email-masked]>  <[email-masked]
> wrote:
RFC4477 described issues identified with dual IP version DHCP interactions 
and also promotes potential 
solutions to solve these issues.one solution may be to modify DHCPv6 to be 
able to return IPv4 information. 

We've discussed that in the past and pretty much rejected it because it 
would add a lot of complexity and the functionality is only useful during 
the transitional period when hosts are running dual-stack.   Is there some 
reason why DHCPv4+DHCPv6 isn't an option?

－－－－－－－－－－－－－－－－－

Hi,Ted
    DHCPv4+DHCPv6 is certainly an option,but have its' problems. Using a 
single DHCPv6 server is another option.You said the functionality is only 
useful during the transitional period when hosts are running 
dual-stack.But the transitional period has lasted a very long time,at 
least 10 years, and there may be another 10 years or more(who knows 
?).When operators plan to deploy IPv6,most of them take the dual-stack 
mechanism as the first step;many transition mechnisam(DS/DS-LITE/NAT444) 
assume that the hosts are running dual-stack.So,maybe we can't use the 
word 'only' to describe  "the transitional period when hosts are running 
dual-stack".
    When RFC4477 was writen(about 2005-2006),many people thought the 
transitional period would be short,but in fact NO. Other protocols such as 
DNS/RADIUS,can serve for both IPv4 and IPv6,why DHCP can't? So, I promote 
the solution as an option,Maybe people should consider the solution again.
   Using a single DHCPv6 server has its' advantages,and would add lots of 
complexity,but DHCPv4+DHCPv6 would also bring lots of complexity during 
the transitional period.

Thanks & Regards
Huyuxing

Ted Lemon <[email-masked]> 
2011-03-01 07:04

收件人
<[email-masked]>
抄送
<[email-masked]>
主题
Re: [dhcwg] What about using a single dhcpv6 server for dual-stack hosts 
to get ipv6/ipv4 settings?

On Feb 14, 2011, at 4:43 PM, <[email-masked]>  <[email-masked]
> wrote:
RFC4477 described issues identified with dual IP version DHCP interactions 
and also promotes potential 
solutions to solve these issues.one solution may be to modify DHCPv6 to be 
able to return IPv4 information. 

We've discussed that in the past and pretty much rejected it because it 
would add a lot of complexity and the functionality is only useful during 
the transitional period when hosts are running dual-stack.   Is there some 
reason why DHCPv4+DHCPv6 isn't an option?

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---

From: Bud Millwood <[email-masked]>
Date: Wed, 2 Mar 2011 15:22:33 +0100

> complexity,but DHCPv4+DHCPv6 would also bring lots of complexity during the transitional
> period.

If OSS interfaces are different between the two servers, then yes, it is
more complex. But I'm not sure that justifies adding DHCPv4 to the DHCPv6
protocol. It sounds more like the OSS interfaces could be better made.

That said, I think we're the only server manufacturer that went so far as to
place both DHCPv4 and DHCPv6 engines inside the same process. By doing so we
got a very coherent set of OSS interfaces for both protocols, so it most
definitely can be done.

Bud Millwood
Weird Solutions, Inc.
http://www.weird-solutions.com
tel: +46 8 758 3700
fax: +46 8 758 3687

---

From: Ted Lemon <[email-masked]>
Date: Sat, 5 Mar 2011 17:19:20 -0500

On Mar 2, 2011, at 9:22 AM, Bud Millwood wrote:
> That said, I think we're the only server manufacturer that went so far as to place both DHCPv4 and DHCPv6 engines inside the same process. By doing so we got a very coherent set of OSS interfaces for both protocols, so it most definitely can be done.

To be clear, the complexity I'm talking about is the additional hair that gets added to the protocol to support IPv4 and IPv6 addresses, instead of just IPv4 addresses.   It's not the operating system layer--as you say, that part is trivial.

There are a lot of problems to be solved here, and we decided, I think rightly, that we didn't know enough about the problem to propose a solution.   Furthermore, DHCPv4 is well-understood, widely deployed technology, so replacing it with something based on DHCPv6 seems to be premature optimization.

---

From: "Bernie Volz (volz)" <[email-masked]>
Date: Sun, 6 Mar 2011 13:02:50 -0600

No, Bud … Cisco Network Registrar also has ONE server that provides both DHCPv4 and DHCPv6 support and most of our configuration objects are the same (except of course the scope and prefix definitions and also the options (there is a v4 set and a v6 set)).

Huyuxing, I don’t see any value in having the DHCPv6 protocol allow configuration of DHCPv4 (at this late point in time). For one, you’ve got to add new functionality into all of the existing client implementations and why would you bother doing that? These clients already support DHCPv4 and it has worked just fine. Invest your time and energy into getting people to move to v6!

-          Bernie

From: [email-masked] [mailto:[email-masked]] On Behalf Of Bud Millwood
Sent: Wednesday, March 02, 2011 9:23 AM
To: [email-masked]
Cc: [email-masked]; Ted Lemon
Subject: Re: [dhcwg]答复: Re: What about using a single dhcpv6 server for dual-stack hosts to get ipv6/ipv4 settings?

	Using a single DHCPv6 server has its' advantages,and would add lots of complexity,but DHCPv4+DHCPv6 would also bring lots of complexity during the transitional period.

If OSS interfaces are different between the two servers, then yes, it is more complex. But I'm not sure that justifies adding DHCPv4 to the DHCPv6 protocol. It sounds more like the OSS interfaces could be better made.

That said,I think we're the only server manufacturer that went so far as to place both DHCPv4 and DHCPv6 engines inside the same process. By doing so we got a very coherent set of OSS interfaces for both protocols, so it most definitely can be done.

Bud Millwood

Weird Solutions, Inc.

tel: +46 8 758 3700

fax: +46 8 758 3687

---

From: [email-masked]
Date: Mon, 7 Mar 2011 10:45:23 +0800

>There are a lot of problems to be solved here, and we decided, I think 
rightly, that we didn't know enough about the problem to >propose a 
solution.   Furthermore, DHCPv4 is well-understood, widely deployed 
technology, so replacing it with something based on >DHCPv6 seems to be 
premature optimization.

I agree with you that there are lots of problems to be solved if we want 
the solution to replace all the current running DHCPv4 device,but that is 
not my proposal. We just add some simple functionnality to DHCPv6 to 
enable the single DHCPv6 sever can provide IPv4 configuration service,that 
would bring some convenience for the small/newly-deployed operators.

Assume that I was a operator,I deployed a IPv6 only network firstly，and 
then I found I have to provide IPv4 service for endusers,so I have to 
depoly DS-LITE or some IPV4-OVER-IPV6 tunnel to enable the end-dual-stack 
host to reach the IPv4 resource.But I want to manage and configure the end 
hosts,what should I do ? Deploy a DHCPv4 sever in my IPv6 only network? 
So,if I can provide IPv4 settings and IPv6 setting using a single DHCPv6 
server,I will be g

Furthermore,if I use the single DHCPv6 sever to provide both IPv4 and IPv6 
settings, I can use the DHCPv6 option 38/37/17 to identify a host which 
have got both IPv4 address and IPv6 address, I can manage the end hosts 
more easily and more controllable. 

I have to restate that I propose the solution JUST AS AN OPTION,not to 
replace the current running DHCPv4.

Thanks & Regards
Huyuxing

2011-03-06 06:19

收件人
Bud Millwood <[email-masked]>
抄送
<[email-masked]>, <[email-masked]>
主题
Re: [dhcwg] Re: Re: What about using a single dhcpv6 server for dual-stack 
hosts to get ipv6/ipv4 settings?

On Mar 2, 2011, at 9:22 AM, Bud Millwood wrote:
> That said, I think we're the only server manufacturer that went so far 
as to place both DHCPv4 and DHCPv6 engines inside the same process. By 
doing so we got a very coherent set of OSS interfaces for both protocols, 
so it most definitely can be done.

To be clear, the complexity I'm talking about is the additional hair that 
gets added to the protocol to support IPv4 and IPv6 addresses, instead of 
just IPv4 addresses.   It's not the operating system layer--as you say, 
that part is trivial.

There are a lot of problems to be solved here, and we decided, I think 
rightly, that we didn't know enough about the problem to propose a 
solution.   Furthermore, DHCPv4 is well-understood, widely deployed 
technology, so replacing it with something based on DHCPv6 seems to be 
premature optimization.

---

From: [email-masked]
Date: Mon, 7 Mar 2011 11:08:03 +0800

>Huyuxing, I don’t see any value in having the DHCPv6 protocol allow 
configuration of DHCPv4 (at this late point in time). For one, you’ve got 
to add >new functionality into all of the existing client implementations 
and why would you bother doing that? These clients already support DHCPv4 
and it >has worked just fine. Invest your time and energy into getting 
people to move to v6!

Nowadays,We can't just move to IPv6 without IPv4,please read the 
information I replied to Mr Ted Lemon.

Thanks & Regards.

"Bernie Volz (volz)" <[email-masked]> 
2011-03-07 03:02

收件人
"Bud Millwood" <[email-masked]>, <[email-masked]>
抄送
<[email-masked]>, "Ted Lemon" <[email-masked]>
主题
RE: [dhcwg]RE: Re: What about using a single dhcpv6 server for dual-stack 
hosts to get ipv6/ipv4 settings?

No, Bud … Cisco Network Registrar also has ONE server that provides both 
DHCPv4 and DHCPv6 support and most of our configuration objects are the 
same (except of course the scope and prefix definitions and also the 
options (there is a v4 set and a v6 set)).
 
Huyuxing, I don’t see any value in having the DHCPv6 protocol allow 
configuration of DHCPv4 (at this late point in time). For one, you’ve got 
to add new functionality into all of the existing client implementations 
and why would you bother doing that? These clients already support DHCPv4 
and it has worked just fine. Invest your time and energy into getting 
people to move to v6!
 
-          Bernie
 
From: [email-masked] [mailto:[email-masked]] On Behalf Of 
Bud Millwood
Sent: Wednesday, March 02, 2011 9:23 AM
To: [email-masked]
Cc: [email-masked]; Ted Lemon
Subject: Re: [dhcwg]答复: Re: What about using a single dhcpv6 server for 
dual-stack hosts to get ipv6/ipv4 settings?

 
That said,I think we're the only server manufacturer that went so far as 
to place both DHCPv4 and DHCPv6 engines inside the same process. By doing 
so we got a very coherent set of OSS interfaces for both protocols, so it 
most definitely can be done.
 
Bud Millwood
Weird Solutions, Inc.

---

From: Ted Lemon <[email-masked]>
Date: Sun, 6 Mar 2011 22:45:58 -0500

On Mar 6, 2011, at 9:45 PM, <[email-masked]>  <[email-masked]> wrote:
> Assume that I was a operator,I deployed a IPv6 only network firstly，and then I found I have to provide IPv4 service for endusers,so I have to depoly DS-LITE or some IPV4-OVER-IPV6 tunnel to enable the end-dual-stack host to reach the IPv4 resource.But I want to manage and configure the end hosts,what should I do ? Deploy a DHCPv4 sever in my IPv6 only network? So,if I can provide IPv4 settings and IPv6 setting using a single DHCPv6 server,I will be g 

Hm, so is your concern that DHCPv4 relay agents aren't present on your IPv6 network, and so you would have to add those?   If not, can you explain what the difficulty is in deploying this DHCP service?   Wouldn't NAT64 be a better choice in a network that's truly v6-only?   Why give the nodes IPv4 addresses at all?   I'm just having trouble seeing how you could have a v6-only network with v4 devices that would need to be configured using DHCPv6.

---

From: [email-masked]
Date: Mon, 7 Mar 2011 14:19:36 +0800

>Hm, so is your concern that DHCPv4 relay agents aren't present on your 
IPv6 network, and so you would have to add >those?   If not, can you 
explain what the difficulty is in deploying this DHCP service?   Wouldn't 
NAT64 be a >better choice in a network that's truly v6-only?   Why give 
the nodes IPv4 addresses at all?   I'm just having >trouble seeing how you 
could have a v6-only network with v4 devices that would need to be 
configured using DHCPv6.

I describe it as the figure shown below:
    --------
   | DHCPv6 |       ------------                  --------------
   | server |------|    IPv6    |     ------     |    IPv4      |
    --------       |   network  |----|6-4 GW|----|   network    |
                   |            |     ------     |              |
                    ------------                  --------------
                        |
                        |
                     --------
                    | Bras   | ----DHCPv6 relay agent
                     --------
                        |
                    ------------
                   |   Access   |
                   |   network  |
                    ------------
                        |
                     -------
                    |  CPE  |
                     -------
                        |
                    ----------
                   |dual stack|
                   |   host   |
                    ----------

I operate the IPv6 network,including the BRAS and the access network.I can 
provide IPv6 service for the hosts,if I want to provide IPv4 service,I 
connet my IPv6 network to the IPv4 network with a gateway(6-4GW in the 
figure).
Because my network is v6-only,I have to setup a IPv4-over-IPv6 tunnel to 
connet the dual-stack host and the IPv4 network. The tunnel may be between 
the BRAS and the 6-4GW,or between the CPE and the 6-4GW(just like DS-LITE 
do).

So, I have to configure IPv4 settings for the hosts.If the single DHCPv6 
server can provide both IPv4 and IPv6 settings, the host send a DHCPv6 
request message including two options:one that request for a IPv4 
address,one for IPv6. The Bras,as a DHCPv6 relay agent,can identify the 
host using dhcpv6 option 37/38,the single DHCPv6 server would alocate both 
IPv6 and IPv4 address for host. I,as the operator,can easily manange the 
server,and have good control of the host.

Yes,as you said, NAT64 is a good choice,but maybe not better.NAT64 has its 
limitations and problems.

Thanks & Regards
Huyuxing

---

From: Ted Lemon <[email-masked]>
Date: Wed, 9 Mar 2011 21:30:51 -0500

On Mar 7, 2011, at 1:19 AM, <[email-masked]>
 <[email-masked]> wrote:
> Yes,as you said, NAT64 is a good choice,but maybe not better.NAT64 has its limitations and problems. 

I think that before you have this discussion here, you probably ought to talk to the softwires and/or behave working groups, or perhaps the routing area directors, about your proposal, and get them to agree that it's a worthwhile solution.   A lot of people are talking about solutions in this space, and I think you need to get the routing end of this nailed down before you start talking about major changes to DHCPv6 to support it.

---

From: [email-masked]
Date: Thu, 10 Mar 2011 11:26:36 +0800

I think that before you have this discussion here, you probably ought to 
talk to the softwires and/or behave working groups, or perhaps the routing 
area directors, about your proposal, and get them to agree that it's a 
worthwhile solution.   A lot of people are talking about solutions in this 
space, and I think you need to get the routing end of this nailed down 
before you start talking about major changes to DHCPv6 to support it.
------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------

There have been some draft talking about the 4over6 transitional mechanism 
in the softwire WG:
draft-ietf-softwire-dual-stack-lite-07 
draft-cui-softwire-host-4over6-03 

These two transitional mechanisms are both the model of IPv4 over 
IPv6,deploying a IPv6-only network firstly and then providing IPv4 service 
over the IPv6 network.They both have the requirements of get IPv4 and IPv6 
settings for the dual-stack hosts,and the solution I proposed would be 
appropriate to them.But the softwires working group would not consider 
about DHCP requirments.
So,I think it is the right time and right place to propose the solution in 
DHC WG.

2011-03-10 10:30

收件人
<[email-masked]>
抄送
Bud Millwood <[email-masked]>, "Bernie Volz (volz)" 
<[email-masked]>, <[email-masked]>
主题
Re: [dhcwg]Re: Re: What about using a single dhcpv6 server for dual-stack 
hosts to get ipv6/ipv4 settings?

I think that before you have this discussion here, you probably ought to 
talk to the softwires and/or behave working groups, or perhaps the routing 
area directors, about your proposal, and get them to agree that it's a 
worthwhile solution.   A lot of people are talking about solutions in this 
space, and I think you need to get the routing end of this nailed down 
before you start talking about major changes to DHCPv6 to support it.