On Nov 22, 2013, at 11:46 AM, Noel Chiappa
<jnc(_at_)mercury(_dot_)lcs(_dot_)mit(_dot_)edu> wrote:
CGNs are expensive. Why would people prefer to maintain them if the
IPv6 infrastructure was working?
Cheaper than customer service calls.
That's almost certainly true now. I'm not talking about now. Really, the
big problem with CGNs is that they don't scale—this is why lw4over6 and MAP
represent a significant and useful innovation.
What I expect to see happen in the market is that in the next decade, CGN will
start to seem old-fashioned, and more and more what will be deployed will be
stateless port-sharing NAT hardware in the core, supported by stateful NATs at
the CP, just like we were doing before the CGN idea got popular.
The nice thing about stateless NATs in the core is that they can be scaled up
and down according to need. So as more traffic is carried over the native
IPv6 network, you can start switching off boxes in the core. You can track
the demand, so you don't switch off boxes that are needed. You can even goose
the switchover by running your IPv4 NATs closer to capacity, forcing traffic
that could go over either transport to go over v6, because it's working better,
and Happy Eyeballs can tell.