Throw me a IPv6 bone (sort of was IPv6 ignorance)

[aid at logic.org.uk (Adrian Bool)]

On 24 Sep 2012, at 17:57, Tore Anderson <tore.anderson at redpill-linpro.com> wrote:

> * Tore Anderson
> 
>> I would pay very close attention to MAP/4RD.
> 
> FYI, Mark Townsley had a great presentation about MAP at RIPE65 today,
> it's 35 minutes you won't regret spending:
> 
> https://ripe65.ripe.net/archives/video/5
> https://ripe65.ripe.net/presentations/91-townsley-map-ripe65-ams-sept-24-2012.pdf

Interesting video; thanks for posting the link.

This does seem a strange proposal though.  My understanding from the video is that it is a technology to help not with the deployment of IPv6 but with the scarcity of IPv4 addresses.  In summary; it simply allows a number of users (e.g. 1024) to share a single public IPv4 address.

My feeling is therefore, why are the IPv4 packets to/from the end user being either encapsulated or translated into IPv6 - why do they not simply remain as IPv4 packets?

If the data is kept as IPv4, this seems to come down to just two changes,

* The ISP's router to which the user connects being able to route packets on routes that go beyond the IP address and into the port number field of TCP/UDP.
* A CE router being instructed to constrain itself to using a limited set of ports on the WAN side in its NAT44 implementation.

Why all the IPv6 shenanigans complicating matters?

Cheers,

aid