mailing list archives
Re: Verizon DSL moving to CGN
From: Owen DeLong <owen () delong com>
Date: Mon, 8 Apr 2013 01:41:34 -0700
On Apr 7, 2013, at 23:27 , Tore Anderson <tore () fud no> wrote:
* Owen DeLong
The need for CGN is not divorced from the failure to deploy IPv6, it
is caused by it.
In a historical context, this is true enough. If we had accomplished
ubiquitous IPv6 deployment ten years ago, there would be no IPv4
depletion, and there would be no CGN. However, that ship has sailed long
ago. You're using present tense where you should have used past.
Respectfully, I disagree. If the major content providers were to deploy
IPv6 within the next 6 months (pretty achievable even now), then the
need for CGN would at least be very much reduced, if not virtually
I was responding to Mikael's claim that pushing content providers to
deploy IPv6 was orthogonal to the need for CGN.
If we put down the history books and focus on today's operational
realities, it *is* orthogonal. If you're an ISP fresh out of IPv4
addresses today, "pushing content providers to deploy IPv6" is simply
not a realistic strategy to deal with it. CGN is.
This does not represent a reason to stop pushing content providers. While
CGN may be a necessary stop-gap measure today for some, there are
many more who aren't facing that decision for a few months. Even for those
that do have to deploy it, the reality is that CGN is fragile, unwieldy, expensive,
and high-maintenance. Further, it provides a lousy customer experience.
The less you have to depend on CGN as an ISP, the better your life will be.
As such, it is even more vital today than it was in history to keep the pressure
for IPv6 content strong.
Clearly your statement here indicates that you see my point that it
is NOT orthogonal, but, in fact the failure of content providers to
deploy IPv6 _IS_ the driving cause for CGN.
I'm not sure why you are singling out content providers, BTW. There are
no shortage of other things out there that have an absolute hard
requirement on IPv4 to function properly. Gaming consoles, Android
phones and tables, iOS phones and tablets, home gateways, software
and apps, embedded devices, ... - the list goes on and on.
All of those things are actually driven primarily by content. iOS phones and
tables are perfectly capable of IPv6 where IPv6 is available over WiFi.
iPhone 5 can do IPv6 over the carrier network. I know, my iPhone 5 works
great with IPv6 on its network. Home gateways are going to need to be
replaced. There are plenty of them that do support IPv6.
Gaming consoles are entirely under the control of content providers.
Most of the embedded devices are either going to need to be replaced
over time, upgraded, or we're going to need some form of set-top box
to deal with them in the future.
Bottom line, content providers are the low-hanging fruit in terms of the
easiest and fastest way to have the biggest impact in reducing the need
for and load on CGN deployments.
If the only missing piece of the puzzle was the lack of IPv6 support at
the content providers' side, IPv6+NAT64 would constitute a perfectly
viable residential/cellular internet service. As far as I know, however,
not a single provider is seriously considering this strategy going
forward. That's telling.
It's not the only piece, just the easiest one to solve immediately with the
 From what I hear, anyway. They used to work fine on IPv6-only
wireless networks, I've seen it myself, but I've been told that it's
taken a turn for the worse over the course of the last year.
Actually it took a brief turn for the worse due to a bug which has now
been (partially) resolved. Apparently the phones used to prefer
IPv6 over carrier if they were on a wireless v4-only network which
ran up some (startling) data charges for some users.
Now they've made it so that if you have a wifi connection, you simply
won't use the cellular network no matter what. This unfortunately means
that you cannot surf an IPv6-only site while you are connected to an
IPv4-only wifi network even if you have dual-stack carrier connectivity,
but I think that's a reasonable tradeoff for now.
Prior to this latest software/carrier settings update, they had simply turned
off IPv6 on the carrier side, but the wifi side has always worked since
one of the later versions of IOS4 or one of the earlier versions of IOS5,
I forget which.