A policy decision by whom? Specifically, how do you do this when IP spaces are controlled by various unfriendly countries around the world? Politics aside, the required technical coordination would be a nightmare. We can barely handle BGP without conflicts as-is.
IPv4 space is also quite limited, and new devices are popping onto networks all the time. I'm not even sure a IP time window is feasible without a full move to IPv6 - something that policy makers have been trying to push on for years without success.
> Specifically, how do you do this when IP spaces are controlled by various unfriendly countries around the world
You begin a "911-certified program" that requires your local ISPs to register their IP ranges with some central authority. The rest is a bunch of detailed but solvable details.
Your idealism when it comes to making this seem more complicatated that it really is seems misplaced.
Your suggestion just isn't realistic when you look at how VoIP systems work in practice. What you usually have are SIP clients talking to SIP servers which then involve a bunch more servers and proxies and a slew of other protocols. SIP traffic from the endpoint and the associated RTP stream could be tunneled, often for very good reason. You can't prevent that with any kind of IP registration scheme because then the client can't roam which defeats the best reason to deploy VoIP in the first place. Providers are routing calls dynamically for reliability and cost reasons. Sometimes when you ask a server to terminate a call it just redirects it elsewhere. Even endpoints can arbitrarily redirect calls.
Ultimately none of the providers involved can know where either end of the call is. We can't even know their IP address for certain, let alone their physical location. What we have for 911 is a form where the customer declares their physical address and a disclaimer warning the customer that should they move then emergency calls will not be routed to the most appropriate call center and the operator will get the wrong address.
There's absolutely nothing we can do to prevent malicious people from abusing it. Any attempt to do so would result in honest users being unable to call for help in emergencies causing far more harm than the abuse we're trying to prevent.
You are not going to convince me, or anyone else who understand the tech, that this is a fundamentally unsolvable technical problem, I promise. It all boils down to compromises between regulation vs freedom, etc.
So, I do take issue when you say things like:
> There's absolutely nothing we can do to prevent malicious people from abusing it.
WRT "just get the government to do it" US federal legislation, specifically not that driven by "terrorism" or "protect the children" (and we don't want any legislation under either label) tends to take years to go from initial idea to law. That doesn't count the years which would be added for compliance. Or the charter and formation of the "central authority".
If we started today, we might get such a law in action sometime in the mid-2020's, at which point ISPs would have switched to IPv6 just to avoid the legislation. You know, maybe it would be a good idea after all /s
My "idealism" is probably better called "pessimism", and is based off a couple of decades watching well-meaning legislation be mangled beyond repair by politicians and corporations, at the city level.
People are complicated and irrational. People in politics are even more complicated and seemingly irrational, since even the best politicians have to balance the wants and needs of thousands of people and the businesses who employ those people. Politicians at the federal level are even more complicated, since they have 50 states, a number of territories, and gigantic corporations to consider.
Even influencing a completely honest political group to do what everyone agrees is the right thing takes a significant amount of time, money, and effort. And if we're honest, they aren't all completely devoted to their constituents, and won't agree that it's the right thing to do.
But then the question shifts to: maybe your country is too large to govern effectively - if you can't make changes like this quickly, something is wrong, I think.
Take any smart phone. No SIM card. Connect it to someone's wifi network, like a coffee shop. Now you can abuse 911 world wide in a completely untraceable manner.
What can possibly be done to prevent this that won't screw people desperately in need of help? It doesn't matter if your government is responsible for a town of 100 people or a country of 1.2 billion. It can't put an owner to each of the billions of smart phones floating around and that's not going to change any time soon.
IPv4 space is also quite limited, and new devices are popping onto networks all the time. I'm not even sure a IP time window is feasible without a full move to IPv6 - something that policy makers have been trying to push on for years without success.