The IPv4 problem
The global pool of IPv4 addresses ran out years ago. Regional ISPs adding subscribers cannot easily obtain enough addresses for everyone, and buying them on the transfer market is expensive.
How carrier-grade NAT works
CGNAT places a translation layer between subscribers and the internet. Subscribers receive private or shared addresses (often from 100.64.0.0/10). When their traffic leaves the network, CGNAT translates it to a public IPv4 address, sharing that address among many subscribers by assigning each a range of ports.
What subscribers notice
Most everyday use — browsing, streaming, social apps — works normally. Some applications that need inbound connections, such as hosting game servers or certain cameras, may need special handling or IPv6.
Logging requirements
Because many subscribers share one address, operators must log which subscriber used which address and port at what time, to respond to lawful requests. Port block allocation reduces log volume by recording blocks rather than individual sessions.
Managed CGNAT
Running CGNAT hardware at scale is expensive. Peer1IX NAT Gateway provides CGNAT as a managed service, including logging, so ISPs can grow without large capital spend.
Plan for IPv6
CGNAT buys time. Deploying IPv6 alongside it reduces the share of traffic that needs translation over time.
