What is the IPv6 ::1/128 address, and how does it functionally compare to the IPv4 127.0.0.1?

• A.::1/128 is the IPv6 unspecified address, used as the source IP in DHCPv6 Discover packets.
• B.::1/128 is the IPv6 loopback address (RFC 4291). Like 127.0.0.1 in IPv4, packets sent to ::1 are processed by the local host's network stack without being transmitted on any physical interface. However, unlike IPv4's 127.0.0.0/8 block, IPv6 uses only the single address ::1 for loopback. Used to test the local IPv6 stack functionality.
• C.::1/128 is the IPv6 default gateway address on every link-local network.
• D.::1/128 is an anycast address shared by all IPv6 routers on a subnet.