I have looked at DS-lite very carefully. First, DS-Lite fits better for cable operators since they have CPE and can have a DS-lite function in the CPE that they control, and that in turn allows them to provide IPv4, IPv6, and dual-stack to the end-host that they do not control. DS-Lite does not fit as well for a mobile phones since it would require a major change to the phone's OS. Second, DS-Lite requires tunneling as well as translation, so it is one more piece of overhead in addition to NAT64 solution. For me, i believe it is less complex to manage a single stack IPv6 host with NAT64 translation than a dual stack host, tunneling infrastructure, as well as NAT44 CGN, which is what DS-lite requires. They both achieve the same result, but I believe in the mobile space there is a quicker time to market as well as more progress toward the end-goal of IPv6-only using NAT64 than DS-lite.
===> DS-lite can work both for fixed and wireless scenario, where you have a laptop/pda/smarphone/tablet that is only configured by the access network with IPv6 but want to access IPv4 content FROM IPv4 applications. This is the main difference between DS-lite and NAT64. NAT64 requires all application on the user device to be IPv6 compatible. Now, that may or may not be an issue. If you are talking about a proprietary wireless device that run only proprietary apps, porting all those apps to IPv6 prior to launching the service may be ok... However, if the device can run external apps, like those coming from an app store, or running pre-existing apps (I¹m thinking about the gazillions apps existing on the iPhone), then a NAT64 solution will force a complete rewrite of every single one of those apps... DS-lite would enable all those apps to keep working. Big difference.
- Alain.