CGNAT – How does it work?

CGNAT is short for Carrier Grade NAT (Network Address Translation) and can also be referred to as LSNAT for Large Scale NAT.

CGNAT is used within carrier and ISP networks to allow the service provider to assign private IP addresses to it’s broadband subscribers and have those translated to a public IP address/port combination for packets going out to the public network. The translation from private to public allows the service provider to have far more broadband subscribers than it does unique public IP addresses. Since IPv4 address space is almost fully consumed, NAT is the predominate way of extending IPv4 space while transitioning to IPv6.