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Re: Verizon DSL moving to CGN
From: Oliver Garraux <oliver () g garraux net>
Date: Sun, 7 Apr 2013 18:43:25 -0400

If I'm an ISP deploying a network for users today, I effectively have to
provide some mechanism to allow those users to get to IPv4 only content.
 There is way too much stuff out there that is IPv4 only today.

Yes, content providers should provide IPv6 access....but if I'm an ISP, I
can't really control that aspect.  If I provide users with a service that
isn't able to connect to 80% of websites (to say nothing of VPN's,
corporate email services, etc, that people may need), I'm not going to have
a whole lot of business.

Now - I completely agree that ISP's must start deploying IPv6 natively.
 Legacy equipment that doesn't support IPv6 is not an acceptable
excuse....its just evidence of poor decision making and short-sighed
purchasing decisions.  CGN clearly isn't ideal and doesn't mitigate the
need for native IPv6 connectivity.  But right now, native IPv6 connectivity
is still not a substitute for some level of IPv4 connectivity, even if its



Oliver Garraux
Check out my blog:  blog.garraux.net
Follow me on Twitter:  twitter.com/olivergarraux

On Sun, Apr 7, 2013 at 4:06 PM, Owen DeLong <owen () delong com> wrote:

On Apr 7, 2013, at 00:31 , Mikael Abrahamsson <swmike () swm pp se> wrote:

On Sun, 7 Apr 2013, Fabien Delmotte wrote:

CGN is just a solution to save time, it is not a transition mechanism
through IPv6
At the end (IPv6 at home) you will need at list :
Dual stack or NAT64/ DNS64

CGN doesn't stop anyone deploying dual stack. NAT64/DNS64 is dead in the
water without other mechanisms (464XLAT or alike).

True... But... Resources deploying/maintaining all of these keep
IPv4-limping along technologies are resources taken away from IPv6

My point is that people seem to scoff at CGN. There is nothing stopping
anyone putting in CGN for IPv4 (that has to be done to handle IPv4 address
exhaustion), then giving dual stack for end users can be done at any time.

Not really...

Face it, we're running out of IPv4 addresses. For basic Internet
subscriptions the IPv4 connectivity is going to be behind CGN. IPv6 is a
completely different problem that has little bearing on CGN or not for
IPv4. DS-Lite is also CGN, it just happens to be done over IPv6 access. MAP
is also CGN.

No, it really isn't. Sufficient IPv6 deployment at the content side would
actually allow the subscriber side to be IPv4 or dual-stack for existing
customers with new customers receiving IPv6-only. The missing piece there
is actually the set-top coversion unit for IPv4-only devices. (Ideally, a
dongle which can be plugged into the back of an IPv4-only device with an
IPv6-only jack on the other side. Power could be done a number of ways,
including POE (with optional injector), USB, or other.

I'm ok with people complaining about lack of IPv6 deployment, but I
don't understand people complaining about CGN. What's the alternative?

IPv6 deployment _IS_ the alternative. They are not orthogonal.


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