That's a really confusing comment. Cgnat is almost universally criticised. IPv6 doesn't need ipv4 addresses. Cgnat and IPv6 are not related.
IPv6 depends on IPv4 addressing if you have downstream devices that need to reach the entire internet. If you go to ARIN they have an explicit policy of allocating IPv4 blocks to facilitate IPv6 deployment.
CGNAT is a term that broadly used to refer to carrier-scale solutions to deal with issues with number exhaustion and dual-stack deployments. What most people think "CGNAT" is, is actually NAT44. https://nfware.com/blog/why-cgnat
Re:Reclaiming IPv4 Class E's 240.0.0.0/4
by mardifoufs on Monday May 27, 2024 @05:48PM
(#40495082)
Maybe they meant NAT64? Not sure though
Mobile providers have IPv6 only networks and use NAT64 with CGNAT and DNS64 to permit access to the legacy internet. No incoming IPv4 ports. CGNAT can serve way more than 32 customers per IP, and they are pooled.
CGNAT at scale functions by assigning a range of ports on a shared v4 address to a downstream customer. You can normally get between a 1:8 and 1:32 "compression ratio."
We still need to free up additional IPv4 to keep the internet growing. Don't let the "just switch to v6" crowd fool you, both solutions need to addressed in parallel.