[v6ops] Re: DHCPv6 PD in a multi-prefix environment

[David Farmer <[e-mail]>]

I already did scenario A.3 in draft-ietf-snac-simple. It is appropriate for
the SNAC router to obtain a ULA prefix instead of a GUA prefix to reduce
the attack surface of the IOT devices.

On Tue, Jul 23, 2024 at 9:33 PM Ted Lemon <[e-mail]> wrote:

> Can you give us an example of a situation where such a decision would need
> to be made?
>
> On Tue, Jul 23, 2024 at 6:48 PM David Farmer <farmer=
> [e-mail]> wrote:
>
>> The classic ISP use case for DHCPv6 PD, as envisioned initially by
>> RFC3633 and integrated into RFC8415, typically expected a single prefix to
>> be delegated to a requesting router from the ISP. Meanwhile, many of the
>> draft-ietf-v6ops-cpe-lan-pd use cases probably expect a subdelegation from
>> this ISP provided prefix. Nevertheless, an RFC7084 CE Router may also have
>> a ULA prefix to subdelegate from, and a ULA prefix may be more appropriate
>> for some of the use cases. Not to mention, there may be prefixes from more
>> than one ISP or additional prefixes while renumbering.
>>
>> Should the delegating router in draft-ietf-v6ops-cpe-lan-pd advertise
>> subdelegations from all prefixes it may have and let the requesting router
>> choose one or more? How does the requesting router know which prefixes it
>> is appropriate to select in what circumstances? If the delegating router
>> doesn't advertise subdelegations from all prefixes, how does it know which
>> prefixes to advertise to which requesting routers?
>>
>> You can also ask the question from the opposite direction: How does the
>> requesting router solicit for a ULA prefix instead of a GUA prefix if that
>> is more appropriate for its use case?
>>
>> These questions came to mind while reading draft-ietf-snac-simple, as it
>> would seem reasonable to want the SCAC router to obtain a ULA prefix from
>> the delegating router and not a GUA prefix, especially in the scenario
>> described in A.3. However, similar questions exist for downstream RFC7084
>> or PD-per-device in a multi-prefix environment.
>>
>> Thanks.
>> --
>> ===============================================
>> David Farmer               Email:[e-mail]
>> Networking & Telecommunication Services
>> Office of Information Technology
>> University of Minnesota
>> 2218 University Ave SE        Phone: [phone]
>> Minneapolis, MN 55414-3029   Cell: 612-812-9952
>> ===============================================
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>

-- 
===============================================
David Farmer               Email:[e-mail]
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
2218 University Ave SE        Phone: [phone]
Minneapolis, MN 55414-3029   Cell: 612-812-9952
===============================================