Re: IPv6 woes - RFC

[Mark Andrews <marka () isc org>]

And how many apartments where covered by that single IP address? Was this
where there is a restriction on other providers so the occupants had no
choice of wireline ISP?

> On 23 Sep 2021, at 09:38, Colton Conor <colton.conor () gmail com> wrote:
>
> Where does this "You can only have about 200-300 subscribers per IPv4
> address on a CGN." limit come from? I have seen several apartment
> complexes run on a single static IPv4 address using a Mikrotik with
> NAT.
>
> On Wed, Sep 22, 2021 at 2:49 PM Baldur Norddahl
> <baldur.norddahl () gmail com> wrote:
> > On Wed, 22 Sept 2021 at 16:48, Masataka Ohta <mohta () necom830 hpcl titech ac jp> wrote:
> > > Today, as /24 can afford hundreds of thousands of subscribers
> > > by NAT, only very large retail ISPs need more than one
> > > announcement for IPv4.
> >
> >
> > You can only have about 200-300 subscribers per IPv4 address on a CGN. If you try to go further than that, for 
> > example by using symmetric NAT, you will increase the number of customers that want to get a public IPv4 of their 
> > own. That will actually decrease the combined efficiency and cause you to need more, not less, IPv4 addresses.
> >
> > Without checking our numbers, I believe we have at least 10% of the customers that are paying for a public IPv4 to 
> > escape our CGN. This means a /24 will only be enough for about 2500 customers maximum. The "nat escapers" drown out 
> > the efficiency of the NAT pool.
> >
> > The optimization you need to do is to make the CGN as customer friendly as possible instead of trying to squeeze the 
> > maximum customers per CGN IPv4 address.
> >
> > Perhaps IPv6 can lower the number of people that need to escape IPv4 nat. If it helps just a little bit, that alone 
> > will make implementing IPv6 worth it for smaller emerging operators. Buying IPv4 has become very expensive. Yes you 
> > can profit from selling a public IPv4 address to the customer, but there is also the risk that the customer just 
> > goes to the incumbent, which has old large pools of IPv4 and provides it for free.
> >
> > Regards,
> >
> > Baldur

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: marka () isc org