Re: [homenet] Let's make in-home ULA presence a MUST !?

[Ted Lemon <[e-mail]>]

On Oct 17, 2014, at 8:46 AM, Lorenzo Colitti <[e-mail]> wrote:
> Yes (but again, it won't be killed by the renumbering; it will be killed *when its source address expires*). But I really doubt that real users have long-lived connections from apps that don't reconnect on failure. Geeks like us might, but that's not really who we should be designing for, because geeks like us will know enough to pick an ISP that doesn't renumber all the time.

I think that we should design our protocols to work independent of what prognostications we are able to make about what users might do today, rather than making decisions that will ensure that certain perfectly valid uses of the network will fail tomorrow.

> Not all ISPs do constant renumbering. My prefix has been static for over two years and it even followed me across an apartment move. And I just have a standard residential service. US ISPs tend to renumber their users very rarely (once every few weeks, at most).

This is true, but I at least have been renumbered by Comcast several times over the past six months, and I am not okay with connections on my local network failing when these renumbering events occur.   And we need to design for all uses cases, not just for your use case.

> Oh, ULAs and stable addressing sound good on paper, sure. But as soon as you actually try to use them, then suddenly there are a boatload of scenarios that you need to deal with like the ones presented by James many messages ago. What happens on splits? What happens on joins? Do you need to keep old ULAs around? How many? Will implementations age them out? (I can tell you the answer to that one: "no"; they're more likely to stop accepting new ones than to have new ones replace old ones). And so on and so forth.

You may have missed the message where I responded to James with concrete proposals for how to solve these problems.   It is entirely possible that if we explore that solution space we will conclude, as you have, that no solution is reliable and not brittle, but I don't think we have explored it, so I think your conclusion that we will not come up with a good solution is premature.