Internet Protocol supplies an inter-network datagram interface. Its basic packet delivery does not itself guarantee arrival, order, absence of duplicates or completion of an application operation. IPv4 and IPv6 are versions of this network-layer protocol.
IPv6 uses 128-bit addresses and a revised packet format. More address space does not remove firewalls or decide which application providers must be trusted.[ref]
Internet Protocol, Version 6 (IPv6) Specification (RFC 8200). §1: expanded addressing and other protocol changes
IPv4 uses 32-bit addresses. Address sharing through network address and port translation is one response to pressure on its globally usable address space.
An IP address identifies an interface or destination according to the relevant Internet Protocol addressing rules. It is not inherently the identity of a person, and address translation can change the address visible across a boundary.
