Re: SLAAC vs DHCPv6 (II)

[Fernando Gont <[e-mail]>]

On 30/1/20 11:14, Michael Richardson wrote:
> 
> Fernando Gont <[e-mail]> wrote:
>      >> But it does violate the recommendation if you use it to enforce how
>      >> many addresses the host can use. The text is:
>      >>
>      >> Due to the drawbacks imposed by requiring explicit requests for
>      >> address space (seeSection 4
>      >> <https://tools.ietf.org/html/rfc7934#section-4>), it is RECOMMENDED
>      >> that the network give the host the ability to use new addresses
>      >> without requiring explicit requests.  This can be achieved either by
>      >> allowing the host to form new addresses autonomously (e.g., via SLAAC)
>      >> or by providing the host with a dedicated /64 prefix.  The prefix MAY
>      >> be provided using DHCPv6 PD, SLAAC with per-device VLANs, or any other
>      >> means.
>      >>
>      >>
>      >> If the network is able to deny a registration, then it's not a
>      >> registration, it's a request.
> 
>      > The network always wins. Folks could run SAVI, and enforce one addrees
>      > per node, even with SLAAC. Yes, you're address wouldn't be rejected
>      > .. it just wouldn't work. The outcome is the same.
> 
> It would be impossible to debug, so the user turns off IPv6, and we all lose.

Well, if the network tries to convey policy, and a host stubbornly wants 
to violate that policy... the host will be shot down, yes.


It would seem to me that:
* We did a BCP saying "host should be able to configure as many 
addresses as possible". -- that's fine... IPv6 is all about the extra 
addresses, right?

* Vendors ship devices with a few Ks of NCE. Maybe we should do 
something in this area?

* Multicast doesn't seem to be playing so nice, either.

The two don't work well with each other. And we don't give the ops 
people the tools that could make the above bullets be nice with each other.

No wonder about the outcome.


-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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