> IPv6's claimed big advantage - a bigger address space - turns out
> not to be an advantage at all - at least in any stage much short of
> completely deployment.
Not surprisingly, I disagree.
> Here's why:
> >> if you have a site which has more hosts than it can get external IPv4
> >> addresses for, then as long as there are considerable numbers of IPv4
> >> hosts a site needs to interoperate with, *deploying IPv6 internally to
> >> the site does the site basically no good at all*.
Actually, in the above scenario, NAT is already a requirement for IPv4
communication with the outside world. So, if you switch to IPv6
internally, use IPv6-IPv4 NATPT (i.e., combination of NAT and IPv6 to
IPv4 translation) you have pretty much the same
functionality/limitation as with IPv4 NAT.
Now, consider someone in the process of deploying massive numbers of
devices (100's of millions) together with the infrastructure to
support them (e.g., wireless). With IPv4, they face not only the
necessity of using NAT to get to outside destinations, but also the
use of NAT _internally_ because there isn't enough private address
space to properly number the internal part of the infrastructure.
In this scenario, IPv6 internally at least gives them end-to-end ness
internally (plus scalability, more robustness, etc., etc.), something
the can't get with IPv4. And it gives them the same set of
issues/headaches when talking to the outside world that they would
have if just using IPv4.
I don't know about you, but it scares me to read the various forecasts
about how wireless will transform the landscape over the next few
years. E.g., more wireless phones with internet connectivity than
PCs. The numbers are just staggering and the associated demand for
addresses will be astonishing. We ain't seen nothing yet.
Thomas
