Hi Lee,

Thank you very much for your interests on 'lightweight 4over6'.

In our consideration, lightweight AFTR is not doing port-range routing. In
this lightweight AFTR, it would firstly lookup a mapping table (recording
[IPv6 address, IPv4 address, Port set]) for a downstream IPv4 packet. Then
after IPv4 packet has been encapsulated into IPv6 packet, it will do IPv6
routing based on different IPv6 addresses. So, lightweight AFTR does not
need to distribute port-set info into FIB and there is no impact on existing
routing architecture between B4 and AFTR.

Actually, the basic idea behind 'lightweight 4over6' is to include
addressing sharing for 'public 4over6', and to enhance DS-Lite for better
scalability. It is a lightweight solution which only keeps customer-based
state in AFTR compared to DS-Lite. And there is also no IPv6 address format
restriction and no IPv6 routing impact on existing network infrastructure.
We have implemented a prototype in our commercial network and find it easy
to deploy in practice.

With regard to so much stateful/stateless discussion, I think actually there
is no solution with totally stateless in the address sharing world. It is
only a matter of fact where to keep the states, either distributed in CPE or
centralized in the core CGN. Given the fact that most existing CPEs can
support NAT already,  our solution is to keep less states in the Core CGN,
while keeping the simplicity of IPv6 addressing and routing.

Sorry to make the discussion even more complicated. Your comments are more
than welcome.

Thanks in advance.

Best wishes


On Tue, Aug 2, 2011 at 1:18 AM, Lee, Yiu <[email protected]> wrote:

> In this case,
> http://tools.ietf.org/id/draft-cui-softwire-b4-translated-ds-lite-01.txt
> could be (modified here) controversial because it will turn AFTR a PRR.
>
> On 8/1/11 7:07 AM, "Satoru Matsushima" <[email protected]>
> wrote:
>
> >If you imagine dynamic port ranges within stateless, it sounds like port
> >range aware routing. I think that it would be controversial.
>
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