Re: [v6ops] Thoughts about wider operational input

[Nick Buraglio <[e-mail]>]

Yes, I know I have harped on this many times and have posted some
simple examples of the behavior to the list. My experience has been, and
continues to be, that if I have dual stacked hosts with A and AAAA records,
and the IPv6 clients are using ULA that IPv6 is never used. In an IPv6-only
environment ULA has no higher priority protocol to supersede the ULA. In
the context of transitioning to an IPv6 world, it is fairly unrealistic to
assume any kind of greenfield, and dual-stack is by and large the standard
"permanently temporary" solution for the vast majority of implementations.
So in this context, which has been 99% of what I have seen until I began
working on the IPv6-only implementation mandated by the USG OMB-M-21-07
document, that was the de facto standard (and will continue to be for
enterprise deployments, in my opinion).
I would be happy to be incorrect about this, honestly it would make my
work-life easier if I was. So, yes, I fully acknowledge that your use case
is absolutely the right one for ULA. For doing a transition in an existing
network (which circles back the the original topic of this thread: getting
enterprises to use IPv6 in a meaningful way), this is a really well put
together descriptions of the every-day implications of trying to use ULA:
https://blogs.infoblox.com/ipv6-coe/ula-is-broken-in-dual-stack-networks/

nb





On Tue, Mar 22, 2022 at 3:20 PM Ted Lemon <[e-mail]> wrote:

> I'm sure you believe this assertion, Nick, but you haven't given us any
> way of understanding why you believe this. In fact we're using ULAs in the
> Thread Border Router to enable IPv6 communication between different
> subnets, which literally could not be done with IPv4. So at least for this
> use case, ULAs work well. Would it work better to have a GUA? Comme ci
> comme ça. On the one hand, prefix delegation and real routing would make
> the solution more general. On the other, GUAs are great for reaching out to
> the internet, which we may or may not want light bulbs to be able to do.
>
> On Tue, Mar 22, 2022 at 9:13 PM Nick Buraglio <[e-mail]> wrote:
>
>> ULA is an operational non-starter in the presence of any dual stacked
>> hosts.  Per its design, it just won't ever use IPv6 in any meaningful way
>> and that time and effort are better served on adding GUA addressing of one
>> kind or another.
>>
>> nb
>>
>>
>>
>> On Tue, Mar 22, 2022 at 2:55 PM Brian E Carpenter <
>> [e-mail]> wrote:
>>
>>> Hi Gert,
>>>
>>> I see that the discussion has been going on while I was sleeping, but I
>>> want to clarify below...
>>> On 22-Mar-22 21:30, Gert Doering wrote:
>>> > Hi,
>>> >
>>> > On Tue, Mar 22, 2022 at 11:42:12AM +1300, Brian E Carpenter wrote:
>>> >> I agree with Jordi that multihoming is a genuine impediment. What
>>> isn't generally realised is that it's a problem of scale when considering
>>> at least 10,000,000 enterprises, much more than it's a problem of IPv6
>>> itself.
>>> >
>>> > What is "an enterprise"?
>>> >
>>> > My stance on this is that for "largely unmanaged SoHo networks" - which
>>> > could be called "small enterprise" - dual-enduser-ISP with dual-/48 or
>>> > NPT66 gets the job done in an easy and scalable way (HNCP would have
>>> > been great, but IETF politics killed it).
>>> >
>>> > "Enterprise that truly need their own independent fully managed network
>>> > with multiple ISP uplinks and fully routed independent address space"
>>> > are probably way less than 10 million...
>>>
>>> I came up with 10 million quite some years ago as a reasonable estimate
>>> of the number of medium to large businesses in the world, all of which
>>> might depend on *reliable* Internet access to survive (and WfH during
>>> COVID has made this even more important recently). So all of them
>>> should have two independent paths to the Internet to assure reliability.
>>> That means two different ISPs (or less good, two completely independent
>>> paths to the same ISP).
>>>
>>> So, if PI addressing is the answer, that really does take us to
>>> 10M /48s to be routed.
>>>
>>> If PA is the answer, that's why I worked on SHIM6 (may it rest in
>>> peace). Which is why I worked on RFC 8028. If that's not the
>>> answer, we're back to NPTv6. Possibly even to ULA+NPTv6.
>>>
>>> > Half of them do not want Internet access anyway, just access to their
>>> > ALGs that will do the filtering and TLS inspection and everything, and
>>> > then out to the Internet as a new TCP session (= could be done with
>>> > DMZ islands of upstream-provider-allocated space just fine).
>>> >
>>> >
>>> > We need to work on our marketing regarding multihoming.  "What is it
>>> that
>>> > you get, what is the cost, which of the variants do you want, and
>>> why...?"
>>>
>>> Yes.
>>>     Brian
>>>
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