Wed Feb 24 07:08:47 UTC 2021

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.


El 24/2/21 3:13, "NANOG en nombre de Owen DeLong via NANOG" < at en nombre de nanog at> escribió:

    > On Feb 22, 2021, at 6:44 AM, nanog at 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.


    I still think that implementing CGN is a good way to burn cash vs. the alternatives, but YMMV.


    > - Jima
    > From: NANOG On Behalf Of Owen DeLong
    > Sent: Sunday, February 21, 2021 16:59
    > To: Steve Saner
    > Cc: nanog at
    > 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:
    > 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
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