To understand why Carrier Grade Network Address Translation (CGN or CGNAT
), also known as Large Scale NAT (LSN) has become a must-have solution and how it works, it is essential to know the primary reason for the emergence of the technology. First, it is necessary to clarify what is meant by "IPv4 and IPv6" because these two protocols are closely related to NAT.What is wrong with iPv4?
There are already about 4.3 billion IPv4 addresses in use in the world. However, today that number is being stretched; no one expected such a rapid growth in consumers over just two decades. In addition, the emergence of this problem is mainly due to the widespread use of mobile devices with the number constantly growing. For more information, see IPv4 exhaustion details
is the fourth version of IP (Internet Protocol), it is the basis of the Internet, and establishes the rules for the functioning of computer networks on the principle of packet exchange. This protocol is responsible for establishing a connection between network nodes (computers, servers, mobile devices, etc.) based on IP addresses.
The global address space is managed by the American non-profit organization IANA
, as well as five regional Internet registrars (ARIN, APNIC, AfriNIC, LACNIC, and RIPE NCC) responsible for assigning IP addresses to end users and local Internet registrars in certain territories. In early 2011, IANA
allocated the remaining blocks of address space to regional operators. Then the regional registrars predicted that the addresses would be exhausted within the next five years. LACNIC and ARIN were among the first regional operators to declare the complete exhaustion of free IPv4 addresses. We decided to address this topic and see how this problem has been solved.What is the alternative to IPv4?
By the mid-1990s, IPv6
was developed as a replacement for IPv4. IPv6 is the next generation of IP. The main advantage of the IPv6 protocol is the increased size of the address from 32 bits to 128 bits, which gives an almost inexhaustible supply of unique IP addresses.
So why not just switch to IPv6? The main reason is the cost. Updating all servers, routers and switches that all this time depended only on IPv4 requires a lot of money and time.