It is not currently possible with the underlying routing technologies, nor do I think it would be desirable, for you to get a single IPv6 address assigned to your device for the entirety of its lifetime.
Firstly, each publicly route-able address (for both IPv4 and IPv6) belongs to a particular network (known as an Autonomous System). The traceroute utility on unix and windows can be used to show you the path from your local network to a particular network, simply by traceroute'ing address that you know are operated by a particular network.
The way this works is a series of routing protocols that ask the question, "Which network routes this address and what is the best path to get there?" and answer it in various ways.
So, I do not think it is possible or desirable for a single publicly route-able IPv6 address to follow a particular device between networks.
Finally, I would like to point out that, even though we can change them, MAC addresses are supposed to be the permanent unique identifier for a particular network interface. I do not think adding an IP equivalent makes any sense, especially when a particular interface may have multiple IP addresses, and a particular machine may have multiple interfaces.
Now I will forget my hackernews password once again, until I am needed.
Firstly, each publicly route-able address (for both IPv4 and IPv6) belongs to a particular network (known as an Autonomous System). The traceroute utility on unix and windows can be used to show you the path from your local network to a particular network, simply by traceroute'ing address that you know are operated by a particular network.
The way this works is a series of routing protocols that ask the question, "Which network routes this address and what is the best path to get there?" and answer it in various ways.
So, I do not think it is possible or desirable for a single publicly route-able IPv6 address to follow a particular device between networks.
Finally, I would like to point out that, even though we can change them, MAC addresses are supposed to be the permanent unique identifier for a particular network interface. I do not think adding an IP equivalent makes any sense, especially when a particular interface may have multiple IP addresses, and a particular machine may have multiple interfaces.
Now I will forget my hackernews password once again, until I am needed.