DualStack (CGNAT) vs Other Transition methods

Douglas Fischer fischerdouglas at gmail.com
Wed Feb 24 13:28:18 UTC 2021

P.S.: Forking thread from CGNAT.

Hello Jordi!

Since our last heated talk about transitions methods(Rosario, 2018?), I
must recognize that the intolerance to other scenarios other than
dual-stack had reduced(mostly because of improvements on the applications
in generral). I'm even considering the possibility of using 464Xlat on some

But I'm still, as it was in 2018, primarily concerned to avoid end-user
support tickets.

And I'm still hooked on some specific issues... For example:
- SIP/Voip Applications, that almost all the providers do not work
correctly on when those streams and connections pass over some v6 only
- Applications with some source-based restrictions(some Internet Banking,
some Compan-VPNs).
- Games (this is the champion of support tickets).

For that, with 464Xlat we still keep in pain...
But using DualStack with Good Quality CGNAT, the support tickets statistics
are reduced to less than 5%.

So, the question here is:
How not use Dual-Stack and keep the support tickets as low as possible?

* "Good Quality CGNAT" means:
 - OBVIOUSLY have an extensive, deep, and GOOD deployment of IPv6(to avoid
as much as possible the use of IPv4)
 - Good rules of CGNAT By-Pass (Ex.: Traffic between customers and Internal
Servers don't need to be NATed.)
 - CGNAT with support to PCP, UPnP, and NAT-Algs. Preferably BPA - Bulk
Port Allocation.

Em qua., 24 de fev. de 2021 às 04:11, JORDI PALET MARTINEZ via NANOG <
nanog at nanog.org> escreveu:

> I did this "economics" exercise for a customer having 25.000.000 customers
> (DSL, GPON and cellular). Even updating/replacing the CPEs, the cost of
> 464XLAT deployment was cheaper than CGN or anything else.
> Also, if you consider the cost of buying more IPv4 addresses instead of
> investing that money in CGN, you avoid CGN troubles (like black listening
> your IPv4 addresses by Sony and others and the consequently
> operation/management expenses to rotate IPv4 addresses in the CGN, resolve
> customers problems, etc.), it becomes cheaper than CGN boxes.
> It's easy to predict that you will buy now CGN and tomorrow you will need
> to buy some new IPv4 addresses because that black listening.
> Regards,
> Jordi
> @jordipalet
> El 24/2/21 3:13, "NANOG en nombre de Owen DeLong via NANOG"
> <nanog-bounces+jordi.palet=consulintel.es at nanog.org en nombre de
> nanog at nanog.org> escribió:
>     > On Feb 22, 2021, at 6:44 AM, nanog at jima.us wrote:
>     >
>     > While I don't doubt the accuracy of Lee's presentation at the time,
> at least two base factors have changed since then:
>     >
>     > - Greater deployment of IPv6 content (necessitating less CGN
> capacity per user)
>     This is only true if the ISP in question is implementing IPv6 along
> side their CGN deployment and only if they get a significant uptake of IPv6
> capability by their end users.
>     > - Increased price of Legacy IP space on the secondary market
> (changing the formula) -- strictly speaking, this presentation was still in
> "primary market" era for LACNIC/ARIN/AFRINIC
>     While that’s true, even at current prices, IPv4 addresses are cheaper
> to buy and/or lease than CGN.
>     > IPv6 migration is not generally aided by CGNAT, but CGNAT deployment
> is generally aided by IPv6 deployment; to reiterate the earlier point, any
> ISPs deploying CGNAT without first deploying IPv6 are burning cash.
>     Yep.
>     I still think that implementing CGN is a good way to burn cash vs. the
> alternatives, but YMMV.
>     Owen
>     >
>     > - Jima
>     >
>     > From: NANOG On Behalf Of Owen DeLong
>     > Sent: Sunday, February 21, 2021 16:59
>     > To: Steve Saner
>     > Cc: nanog at nanog.org
>     > Subject: Re: CGNAT
>     >
>     >
>     > On Feb 18, 2021, at 8:38 AM, Steve Saner wrote:
>     >
>     >> We are starting to look at CGNAT solutions. The primary motivation
> at the moment is to extend current IPv4 resources, but IPv6 migration is
> also a factor.
>     >
>     > IPv6 Migration is generally not aided by CGNAT.
>     >
>     > In general, the economics today still work out to make purchasing or
> leasing addresses more favorable than CGNAT.
>     >
>     > It’s a bit dated by now, but still very relevant, see Lee Howard’s
> excellent research presented at the 2012 Rocky
>     > mountain v6 task force meeting:
>     >
>     > https://www.rmv6tf.org/wp-content/uploads/2012/11/TCO-of-CGN1.pdf
>     >
>     > Owen
>     >
>     >
>     > We've been in touch with A10. Just wondering if there are some
> alternative vendors that anyone would recommend. We'd probably be looking
> at a solution to support 5k to 15k customers and bandwidth up to around
> 30-40 gig as a starting point. A solution that is as transparent to user
> experience as possible is a priority.
>     >
>     > Thanks
>     >
>     > --
>     > Steve Saner
>     > ideatek HUMAN AT OUR VERY FIBER
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Douglas Fernando Fischer
Engº de Controle e Automação
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