Re: Generic anycast addresses...

Hi Bob,

On Thu, 30 May 2019 at 10:48, Bob Hinden <bob.hinden@gmail.com> wrote:
>
> Ted,
>
> > On May 29, 2019, at 5:41 PM, Ted Lemon <mellon@fugue.com> wrote:
> >
> > Indeed, the propagation pattern of a ULA would work nicely for this, but there’s no way to do this automatically.   I might have (and indeed unfortunately it’s common to have) more than one ULA on a constrained network.   How do I pick?   :)
> >
> > So what I really want is indeed something that is treated like a ULA, but that can be a constant, and not something that has to be derived.
>
> We when ULAs were being developed, there was a notion of centrally assigned ULAs.  It’s not currently defined, but that’s was the original intent for having the “L” bit in the prefix.  See RFC4193.
>

I would guess Ted is looking for well-known addresses that can be
encoded in applications, similar to how well-known multicast addresses
can be encoded in applications. That would mean they're not unique,
contrary to the U.

Having deployed anycast DNS service in the past, being a reviewer of
RFC 7094, and having thought about this sort of problem space for a
while, I came to the conclusion that there should be a formal class of
IPv6 anycast addresses that include fine grained scopes. A separate
class of addresses is also what the authors of  RFC 1546 suggested as
an option for anycast support.

"IPv6 Formal Anycast Addresses and Functional Anycast Addresses"
https://tools.ietf.org/html/draft-smith-6man-form-func-anycast-addresses-00

Regards,
Mark.

> Bob
>
>
>
>
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