What is Carrier Grade NAT (CGN) all about? What are the problems associated with using it? What role, if any, should it play in networks during the transition from IPv4 to IPv6?
At the recent North American IPv6 Summit, Chris Grundemann of Cable Labs addressed exactly these points – and now has published a blog post with his CGN slides and some additional commentary:
It’s a good set of slides looking at a challenging issue. For some ISPs who are lagging behind with moving to IPv6, CGN looks like an attractive option to bypass IPv6 and just stay with IPv4. But as Chris notes, their testing found that a good number of popular services, including VoIP and online gaming, would break or at least have degraded performance in typical CGN deployments.
Chris also notes that he is available to speak with anyone interested in learning more about CGN. Thanks to Chris for making these slides available for us all to see.
 CGN is also sometimes referred to as “Large Scale NAT” or “LSN”.