Re: [homenet] Introduction to draft-ietf-homenet-simple-naming

[Ted Lemon <[e-mail]>]

On May 31, 2018, at 4:27 PM, Michael Thomas <[e-mail]> wrote:
> With a CNAME, you wouldn't need to deprecate the other... it's just an alias that you have control of.
> From the UI perspective, whatever is presenting names to the user can prefer the human-given name over
> the auto-generated name, right? We wouldn't need to standardize anything then.

Michael, I don't think you've really understood the issue here.   Let me try and explain it all at once, since the explanation was actually scattered across several messages.

There are two pieces to this.   First, there's the thing that publishes the name.  That's DNSSD.   There's no problem with that end of things.   If you change the name, the device just appears with its new name, and everything is fine.   That's our piece of the puzzle, and it already works.

The problem is that hosts tend to remember names.   On MacOS, for instance, if you configure a printer, the host remembers the printer forevermore.   It's no problem to configure a new printer, but if you change the name that the printer advertises, there will be a stale configuration on the host pointing to the old name, and the user will have to configure a new printer to get access to the old printer.

So what we are talking about here actually breaks DNSSD's good behavior.   We don't want DNSSD to publish two names.   We don't want DNSSD to publish a CNAME.   That would just be extra garbage that would have to be maintained forever.

What we want is a way for the host to notice that the device's name has changed.   We want the device to have some identity other than the name that doesn't change when the name changes.   And we actually have this in the registration protocol, which is another draft being published in the DNSSD working group.   That protocol has the host generating a public/private key pair, and using the public key as an identity.   It uses this identity to claim the name, but it wouldn't be that much work to also specify that hosts should use that identifier to notice that a device has a new name and update the name in the user interface.

When I talk about UI, I'm really talking about the API behind the UI.   Having a management API for homenet would be a good thing.   Possibly it could just be done with HNCP.