Re: [v6ops] DHCPv6/SLAAC Make Hosts Confusing-//RE: new draft: draft-liu-bonica-v6ops-dhcpv6-slaac-problem

"Weil, Jason" <> Tue, 29 October 2013 14:50 UTC

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From: "Weil, Jason" <>
To: "Liubing (Leo)" <>, Wuyts Carl <>, "" <>
Date: Tue, 29 Oct 2013 10:44:14 -0400
Thread-Topic: [v6ops] DHCPv6/SLAAC Make Hosts Confusing-//RE: new draft: draft-liu-bonica-v6ops-dhcpv6-slaac-problem
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Subject: Re: [v6ops] DHCPv6/SLAAC Make Hosts Confusing-//RE: new draft: draft-liu-bonica-v6ops-dhcpv6-slaac-problem
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First I wanted to say this is useful work and I support it.

This topic in this email reminds me of an issue that we have run across
that might be relevant to your draft:

The use case involves a home network whose gateway router sets M=1 and A=1
in order to provide DHC and and SLAAC for hosts that do not implement a
DHC client. If the DHCPv6 Server is implementing IP assignment using
interface-identifier and using the same prefix as advertised in the PIO
(assuming the server resides on the router advertising the PIO) with the A
bit set, hosts that support SLAAC and a DHCPv6 client could construct the
same address using DHC as the one they construct using SLAAC. What is not
clear is what hosts should do in this situation. IMO, there is a benefit
if hosts that support both SLAAC and DHCPv6 construct the address and
prefer the DHC address over the SLAAC address. The benefit is that you
reduce the number of active addresses and all hosts end up with a single
address per prefix administered in this fashion.

Of course if your DHC Server implements another assignment algorithm (e.g.
Random) then your hosts that support both may end up with 2 addresses out
of the same prefix.



On 10/23/13 7:19 AM, "Liubing (Leo)" <> wrote:

>> From: Wuyts Carl []
>> Nevertheless, I can imagine you prefer the dhcpv6 over RA, but I doubt,
>> looking at the big number of devices taking part in this these days
>> bulbs, etc) that they will all start supporting dhcpv6 client, not a
>>chance I'm
>> afraid.
>[Bing] Agreed. These lightweight/embed systems might become an important
>part of the IPv6 net. ND allows minimal management burden for them.
>Beyond address space, in my mind SLAAC is the most obvious advantage
>comparing to IPv4.
>> Thx for feedback
>> Regs
>> Carl
>> -----Original Message-----
>> From: []
>> Sent: woensdag 23 oktober 2013 12:25
>> To: Wuyts Carl
>> Cc:;;;
>> Subject: Re: [v6ops] DHCPv6/SLAAC Make Hosts Confusing-//RE: new draft:
>> draft-liu-bonica-v6ops-dhcpv6-slaac-problem
>> > To be honest, I haven't kept up with the full exchange on this topic,
>> please disregard my question if it is not relative to this discussion.
>> >
>> > I read below that, if netmask and def gw would be added on handing out
>> dhcpv6, "I can finally get rid of RA messages".
>> > But what with hosts NOT supporting dhcpv6 client in this case ?  I
>> be fully wrong, but I cannot imagine it can be 100% enforced upon each
>> vendor to include dhcpv6 client support?
>> It worked for IPv4. Yes, I realize IPv6 is different, and the target
>>market is
>> different (e.g. light bulbs).
>> Nevertheless - as an ISP, I am going to require DHCPv6 for dynamic
>> customers. I would be very happy if I only needed DHCPv6 and could do
>> without RA. (Note RA != ND/NS)
>> Steinar Haug, AS 2116
>v6ops mailing list

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