Re: [dhcwg] [EXTERNAL] Re: I-D Action: draft-templin-duid-ipv6-01.txt

[Bob Hinden <[e-mail]>]

Fred,

> On Jan 12, 2021, at 3:05 PM, Templin (US), Fred L <[e-mail]> wrote:
> 
> Ole,
> 
>> -----Original Message-----
>> From: [e-mail] [mailto:[e-mail]]
>> Sent: Tuesday, January 12, 2021 1:34 PM
>> To: Templin (US), Fred L <[e-mail]>
>> Cc: Bob Hinden <[e-mail]>; dhcwg <[e-mail]>; 6man WG <[e-mail]>; Dickson (US), Sean M
>> <[e-mail]>
>> Subject: [EXTERNAL] Re: I-D Action: draft-templin-duid-ipv6-01.txt
>> 
>> Fred,
>> 
>> It's unclear to me what the purpose of putting an IPv6 address in the DUID is. Would you mind clarifying that?
> 
> I will add words to the next draft version.

How about telling us now.

Bob


> 
>> Are you also aware of the following restriction in RFC8415:
>>   "Clients and servers MUST treat DUIDs as opaque values and MUST only
>>   compare DUIDs for equality.  Clients and servers SHOULD NOT in any
>>   other way interpret DUIDs."
> 
> Yes, but then what is the reason why we currently have 4 DUID types instead
> of just 1? If the text you quoted above is all there was to it, and end of story,
> there would never be a need to differentiate DUID-LL from DUID-LLA from
> DUID-EN from DUID-UUID. So, this suggests there is more to the story than
> just the short text you quoted above. And, the community has supported the
> definition of new DUIDs in the past (e.g., DUID-UUID).
> 
> Thanks - Fred
> 
>> Best regards,
>> Ole
>> 
>>> On 12 Jan 2021, at 19:40, Templin (US), Fred L <[e-mail]> wrote:
>>> 
>>> Bob, please see my subsequent reply to Eric Vyncke that discusses motivation:
>>> 
>>> https://mailarchive.ietf.org/arch/msg/ipv6/yOfWHSnt36Hvjr44OERjK0OFvhw/
>>> https://mailarchive.ietf.org/arch/msg/dhcwg/YZq_aPf1C82ZFT_bTdXOXVXTPW0/
>>> 
>>> Per your comment, perhaps a new section on "motivation" could be added
>>> to the draft?
>>> 
>>> Thanks - Fred
>>> 
>>>> -----Original Message-----
>>>> From: Bob Hinden [mailto:[e-mail]]
>>>> Sent: Tuesday, January 12, 2021 10:22 AM
>>>> To: Templin (US), Fred L <[e-mail]>
>>>> Cc: Bob Hinden <[e-mail]>; Mark Smith <[e-mail]>; dhcwg <[e-mail]>; IPv6 List
>>>> <[e-mail]>; Dickson (US), Sean M <[e-mail]>
>>>> Subject: Re: I-D Action: draft-templin-duid-ipv6-01.txt
>>>> 
>>>> Fred,
>>>> 
>>>> Mark asked:
>>>> 
>>>> "I don't understand what problem this is trying to solve or see any
>>>> benefits of it. What is wrong with existing DUIDs?”
>>>> 
>>>> I have the same question.   I read the draft but have no idea why this is needed.
>>>> 
>>>> Bob
>>>> 
>>>> 
>>>>> On Jan 12, 2021, at 8:26 AM, Templin (US), Fred L <[e-mail]> wrote:
>>>>> 
>>>>> Mark, thanks for the comments. I gather your concern is for the longevity and
>>>>> immutability of the IPv6 address that would go into the DUID, since DUIDs are
>>>>> meant to identify the device and not change over time. But, there are IPv6
>>>>> address generation methods that generate addresses not for the purpose of
>>>>> assigning them to a physical interface (e.g., Ethernet, WiFi and the like), but
>>>>> instead to provide a unique node ID for the device that never changes
>>>>> [RFC7401][draft-ietf-drip-rid]. Also, [RFC7721] mentions several other IPv6
>>>>> address generation methods that could be considered for use for generating
>>>>> a unique node ID, and other IPv6 address generation methods intended to
>>>>> create a unique node ID could be defined in the future.
>>>>> 
>>>>> So, again, this is not about using an IPv6 address assigned to a physical interface
>>>>> as a DUID; it is about using an IPv6 address that was intentionally generated to
>>>>> be a unique identifier for the node and may also be assigned to a virtual interface.
>>>>> 
>>>>> Thanks - Fred
>>>>> 
>>>>>> -----Original Message-----
>>>>>> From: Mark Smith [mailto:[e-mail]]
>>>>>> Sent: Monday, January 11, 2021 5:32 PM
>>>>>> To: Templin (US), Fred L <[e-mail]>
>>>>>> Cc: [e-mail]; dhcwg <[e-mail]>; Dickson (US), Sean M <[e-mail]>
>>>>>> Subject: Re: FW: I-D Action: draft-templin-duid-ipv6-01.txt
>>>>>> 
>>>>>> 
>>>>>> Hi Fred,
>>>>>> 
>>>>>> I don't understand what problem this is trying to solve or see any
>>>>>> benefits of it. What is wrong with existing DUIDs?
>>>>>> 
>>>>>> DHCP Unique IDentifiers are, per RFC 8415,
>>>>>> 
>>>>>> "...  designed to be unique across all DHCP clients and servers, and stable
>>>>>> for any specific client or server.  That is, the DUID used by a
>>>>>> client or server SHOULD NOT change over time if at all possible; for
>>>>>> example, a device's DUID should not change as a result of a change in
>>>>>> the device's network hardware or changes to virtual interfaces (e.g.,
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Mrugalski, et al.            Standards Track                   [Page 32]
>>>>>> 
>>>>>> ________________________________
>>>>>> 
>>>>>> 
>>>>>> RFC 8415                      DHCP for IPv6                November 2018
>>>>>> 
>>>>>> 
>>>>>> logical PPP (over Ethernet) interfaces that may come and go in
>>>>>> Customer Premises Equipment routers).  The client may change its DUID
>>>>>> as specified in [RFC7844]."
>>>>>> 
>>>>>> The only IPv6 address that I can think of that might come close to
>>>>>> meeting those requirements would be an EUI-64 derived Link-Local
>>>>>> address, and that is assuming that the EUI-64/hardware MAC address
>>>>>> never changes. MAC address randomisation and the RFC8064
>>>>>> recommendation for use of RFC7217 for SLAAC means that Link-Local
>>>>>> addresses may not meet the DUID requirements above either (RFC7217 can
>>>>>> result in link-specific link-local addresses (specifically the IID
>>>>>> portion is link specifc), even though the link-local prefix itself is
>>>>>> constant across all links).
>>>>>> 
>>>>>> There's also a circular dependency if the DUID is based on a GUA or
>>>>>> ULA address and DHCPv6 is to then be used for stateful GAU/ULA address
>>>>>> assignment, unless you mandated that SLAAC and stateful DHCPv6 are
>>>>>> used in parallel so that SLAAC could be used to derive the DUID that
>>>>>> is then used to acquire further ULA/GUA addresses via stateful DHCPv6
>>>>>> IA_NAs and IA_TAs.
>>>>>> 
>>>>>> "The DUID-V6ADDR may appear in DHCPv6 and/or other protocol control
>>>>>> messages (such as IPv6 ND) within a service domain when a unique ID
>>>>>> based on an IPv6 address is required."
>>>>>> 
>>>>>> In the latter case, why not use IPv6 addresses themselves? Using
>>>>>> DHCPv6 Unique Identifiers outside of the DHCP protocol would be an
>>>>>> abuse of a DUID.
>>>>>> 
>>>>>> Regards,
>>>>>> Mark.
>>>>>> 
>>>>>> On Tue, 12 Jan 2021 at 05:47, Templin (US), Fred L
>>>>>> <[e-mail]> wrote:
>>>>>>> 
>>>>>>> Hi, more and more IPv6 address generation methods are being specified that
>>>>>>> intend to generate IPv6 addresses that are highly likely to be unique on either
>>>>>>> a global scale or unique within a bounded service domain. So much so, that
>>>>>>> some address generation methods intend for the IPv6 addresses to be usable
>>>>>>> as node identifiers.
>>>>>>> 
>>>>>>> Recognizing this, this document proposes a new DHCPv6 DUID type known
>>>>>>> as "DHCP-V6ADDR" that includes an IPv6 address in the body of the DUID. In
>>>>>>> this way, IPv6 addresses produced by address generation methods intending
>>>>>>> to generate a node ID can be used as unique identifiers in DHCPv6 message
>>>>>>> exchanges. This would introduce a single new DUID type, for which the IANA
>>>>>>> allocation policy is  "standards action".
>>>>>>> 
>>>>>>> Alternatively, a separate DUID type could be allocated for each IPv6 address
>>>>>>> generation method. However, that approach may result in additional IANA
>>>>>>> allocations and would require implementation updates every time a new
>>>>>>> address generation method is specified. Hence, a single generic DUID type
>>>>>>> for all IPv6 generation methods is proposed, but open for discussion.
>>>>>>> 
>>>>>>> Comments on the list welcome.
>>>>>>> 
>>>>>>> Fred
>>>>>>> 
>>>>>>> -----Original Message-----
>>>>>>> From: I-D-Announce [mailto:[e-mail]] On Behalf Of [e-mail]
>>>>>>> Sent: Monday, January 11, 2021 10:21 AM
>>>>>>> To: [e-mail]
>>>>>>> Subject: I-D Action: draft-templin-duid-ipv6-01.txt
>>>>>>> 
>>>>>>> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>>>>>>> 
>>>>>>> 
>>>>>>>      Title           : The IPv6 Address-based DHCPv6 Unique Identifier (DUID-V6ADDR)
>>>>>>>      Author          : Fred L. Templin
>>>>>>>      Filename        : draft-templin-duid-ipv6-01.txt
>>>>>>>      Pages           : 7
>>>>>>>      Date            : 2021-01-11
>>>>>>> 
>>>>>>> Abstract:
>>>>>>> This document defines a new DHCPv6 Unique Identifier (DUID) type
>>>>>>> called DUID-V6ADDR that contains a single 128 bit IPv6 address.
>>>>>>> DUID-V6ADDR makes it possible for devices to use suitably-derived
>>>>>>> unique IPv6 addresses to identify themselves to DHCPv6 servers and/or
>>>>>>> other network nodes.
>>>>>>> 
>>>>>>> 
>>>>>>> The IETF datatracker status page for this draft is:
>>>>>>> https://datatracker.ietf.org/doc/draft-templin-duid-ipv6/
>>>>>>> 
>>>>>>> There are also htmlized versions available at:
>>>>>>> https://tools.ietf.org/html/draft-templin-duid-ipv6-01
>>>>>>> https://datatracker.ietf.org/doc/html/draft-templin-duid-ipv6-01
>>>>>>> 
>>>>>>> A diff from the previous version is available at:
>>>>>>> https://www.ietf.org/rfcdiff?url2=draft-templin-duid-ipv6-01
>>>>>>> 
>>>>>>> 
>>>>>>> Please note that it may take a couple of minutes from the time of submission
>>>>>>> until the htmlized version and diff are available at tools.ietf.org.
>>>>>>> 
>>>>>>> Internet-Drafts are also available by anonymous FTP at:
>>>>>>> ftp://ftp.ietf.org/internet-drafts/
>>>>>>> 
>>>>>>> 
>>>>>>> _______________________________________________
>>>>>>> I-D-Announce mailing list
>>>>>>> [e-mail]
>>>>>>> https://www.ietf.org/mailman/listinfo/i-d-announce
>>>>>>> Internet-Draft directories: http://www.ietf.org/shadow.html
>>>>>>> or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
>>>>>>> 
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