Slashdot: UK ISP PlusNet Testing Carrier-Grade NAT Instead of IPv6

Cameron Byrne cb.list6 at
Sat Jan 19 03:27:11 UTC 2013


On Fri, Jan 18, 2013 at 6:56 PM, Constantine A. Murenin
<mureninc at> wrote:
> On 16 January 2013 08:12, fredrik danerklint <fredan-nanog at> wrote:
>> From the article:
>> "Faced with the shortage of IPv4 addresses and the failure of IPv6 to take
>> off, British ISP PlusNet is testing carrier-grade network address
>> translation CG-NAT, where potentially all the ISP's customers could be
>> sharing one IP address, through a gateway. The move is controversial as it
>> could make some Internet services fail, but PlusNet says it is inevitable,
>> and only a test at this stage."
>> I'm only here to bring you the news. So don't complain to me...
> It is obvious that implementing CGN requires a lot of extra resources
> and a lot of hardware/firmware support for both CPE and operator
> equipment (the latter from both technical and legal-compliance
> reasons, and both the former and the latter in order to implement some
> kind of UPnP-compatible support to still allow some kind of p2p apps
> to somehow function).
> And this is at a time when a lot of the world internet traffic has
> already moved to IPv6, and all major content providers that account
> for most of the traffic today already support native IPv6: Google,
> YouTube and FB.
> Wouldn't it be better instead of the untested, unscalable and dead-end
> IPv4 CGN to massively start implementing single-stacked IPv6 with
> NAT64 at the ISP and *464XLAT* within the CPE RG?  (With 464XLAT, you
> wouldn't even need a potentially troublesome DNS64.)  This way,
> instead of having to account for subscriber growth presenting
> scalability issues on your limited IPv4 resources and CGN-related
> concerns, you can instead account for the content growth of
> IPv6-enabled sites, and, basically, have to plan for just about no
> extra IPv4 scaling budget whatsoever, since with every X subscribers
> that still need IPv4, you'll have every XX old subscribers that will
> be moving closer to being IPv6-only.  And with every year, a single
> IPv4 address used for NAT64 will be perfectly able to scale up to
> serve more and more customers, since fewer and fewer people will need
> IPv4 connections.
> So:
> With CGN, we get to the same old chicken-and-egg story:  lack of IPv6
> deployment and content/app support, yet an even more imminent shortage
> of IPv4 addresses (and with every new customer you'll be so much more
> closer to it) and the scalability and legal issues.
> With 464XLAT on the CPE RG and NAT64 at the carrier instead, you get
> all the benefits of CGN (namely, all non-p2p IPv4-only apps and
> services will still work perfectly fine), but only a couple of the
> drawbacks.  And it'll actually put the correct pressure for both
> content and application developers to immediately switch to IPv6, and
> avoid you, the operator, from having to be spending the extra
> resources and having extra headaches on the IPv4 address shortage.  It
> really makes no sense that any company would still want to invest a
> single dime into CGN when instead they could be investing in IPv6 with
> NAT64 and CPE RGs with 464XLAT.

Brilliant so far ...

> I honestly think that 464XLAT can potentially solve all the chicken
> and egg problems that the big players have been having.  Supposedly,
> that's how T-Mobile USA is planning to move their network forward.
> (I'm certainly looking towards the day when I could finally enable
> IPv6 on a Google Nexus on T-Mo.)

OK... i am wading into dangerous territory now:  Why are you waiting?

This page has the 464XLAT software and procedure for Nexus S, Galaxy
Nexus, as well as apk for any rooted Android that can handle IPv6 on

Or for the more pure IPv6-only NAT64/DNS64 out-of-the-box experience

> On the other hand, it's really strange that 464XLAT is so brand bloody
> new when IPv6 itself, as well as even NAT64 and DNS64, have been there
> for ages.  The idea of 464XLAT is just so ingeniously straight and
> simple!  Somewhat similar to 6rd, I guess.

Well, i certainly fought it as long as i could.  I was really drinking
the Kool-Aid that apps that could not support IPv6 would be
de-selected since they were unfit for the internet.  I figured
evolution would win, but inertia was certainly making things too slow,
thus we needed a way to make IPv4-apps (cough cough Skype, Netflix
Android App, ...) work on IPv6.

> I think that instead of any kind of CGN, all residential (and mobile)
> broadband connections should be IPv6-only with NAT64 and 464XLAT.
> That'll basically solve all the actual problems with one stone: lack
> of IPv6 deployment from content publishers and IPv6 application
> support (from app developers with no IPv6), and the immediate shortage
> of the IPv4 addresses.
> Cheers,
> Constantine.

Rock on.  I have been on IPv6-only + NAT64/DNS64 for 2 years on mobile
full-time, works fine for all my use cases (i dont use skype, voice
minutes are close enough to free for many people)


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