Networking → [ipv6] ULA for cable modem GUI access?

So I've been batting around an idea, and wanted to get some input from the general IPv6 crowd.

Traditionally, cable modem manufacturers have used the RFC1918 private IPv4 address 192.168.100.1 as the standard address for modem diagnostics on the customer facing interface.

With the evolution of IPv6 in service provider networks, a desire has been expressed for an equivalent IPv6 address.

The IPv6 RFC4193 Unique Local Address fd00::100:1 could be used as a complement to the IPv4 private address in use today. (I would request dual stack 192.168.100.1/fd00::100:1 access to the GUI)

There has been discussion about using a URL for diagnostics, but this adds an additional layer of complexity, and could prove difficult to get manufacturers to settle on a single hostname.

I know I'll need to get the modem chipset manufacturers as well as the modem vendors to implement this in their code, so it will be a long process, but I wanted to see what people thought about it before I head down that road.

Thoughts?

Any IPv6-capable interface already comes up with a Link-Local address (FE80::/64) that's based on the MAC address of the interface using EUI-64. This address can always be printed on the side of the modem to be used for local access.

Since this is the case, why do you also need a Unique Local in FD00::/64 ?

For the same reason that 192.168.100.1 is so popular and commonly used. It will be the same IP for every modem you encounter.
If you're a technician or a technically competent customer, would you rather turn the modem over and locate the IP, and then type »:[fe80::da67:2243:e59c:10f5], or »[fd00::100:1]? (as well as try and remember that IP if the modem is in another room, or hard to reach)

I suppose it would make it more convenient. But any agreement between modem/chipset manufacturers would most likely have to be informal -- I doubt any governing body or RFC would actually formalize this rule.

I would agree, this sort of thing might be useful. The current link local addresses are just that: local to the link. My cable modem is not on the same link as my workstation; there's a (Linux) router inbetween. But I'd have to agree with other posters, the .100.1 notion is just de facto, there's no standard for it. Although maybe some standard would be nice, I'm sure just as they all figured out .100.1, they'll figure out some appropriate v6 equivalent.

If it was a DOCSIS standard... I think this would be a good idea.

You keep using that word, I don't think it means what you think it means.

Or in other words, with ULA there is a randomly generated Global ID that gets generated as part of the local part of ULA that is large enough that the odds of collision with another Global ID is quite low.

That's not to say that this is a bad idea, but that the ULA space is not the appropriate place to put it.

What address space do you think would be more appropriate?

I think ULA would be the appropriate space, something like: fd00::192:168:100:1 or fd00:192:168:100::1

LLMNR with well known name might be even easier for people to get to.

But with ULA every site is supposed to generate 40 bits of random addressing after the fd00... and then you are supposed to break that up with 16 bits of subnetting if need be for your site.
That way if two sites merge, their addressing is not likely to have to change.