> Extending address is fully possible, and if we drop requirement that the extended part be individually routable, even simple.
No it is not:
* You also have to deploy new DNS code to handle a new record type to handle longer "IPv4+" addresses.
* You also have to deploy new OS and library code with new socket, etc, APIs because all in_addr_t definitions and data structures are 32-bit-only.
If a public service has a "IPv4+" address, how does a not-IPv4+ host, or not-IPv4+ compliant code handle it? If you want >4B addresses you have to tweak all the code that touches address structures. You have to (re)deploy code on all the network elements that touch the packet bits: all the end-user applications (browsers, chat clients, etc), all the end-user operating systems, all the middle-boxes, all the routers. If you have network devices and segments between the public service and the client that are not IPv4+ compliant, you have to configure the clients to send the IPv4+ traffic to translation boxes that are IPv4+ compliant.
Basically all the stuff that is happening with IPv6.
No it is not:
* You also have to deploy new DNS code to handle a new record type to handle longer "IPv4+" addresses.
* You also have to deploy new OS and library code with new socket, etc, APIs because all in_addr_t definitions and data structures are 32-bit-only.
If a public service has a "IPv4+" address, how does a not-IPv4+ host, or not-IPv4+ compliant code handle it? If you want >4B addresses you have to tweak all the code that touches address structures. You have to (re)deploy code on all the network elements that touch the packet bits: all the end-user applications (browsers, chat clients, etc), all the end-user operating systems, all the middle-boxes, all the routers. If you have network devices and segments between the public service and the client that are not IPv4+ compliant, you have to configure the clients to send the IPv4+ traffic to translation boxes that are IPv4+ compliant.
Basically all the stuff that is happening with IPv6.