Today we'll be discussing CGNAT, or Carrier-Grade Network Address Translation. This technology was created to address the finite number of public IP addresses that were available under the IPv4 protocol. In the 1980s, it was anticipated that each computer would have its own unique public IP address, but the total number of addresses available, 4 billion, eventually ran out. As a result, IPv6 was developed to address the limited address space of IPv4, but it is not backwards compatible.