misunderstanding scale

Justin M. Streiner streiner at cluebyfour.org
Sat Mar 22 19:35:53 UTC 2014

On Sat, 22 Mar 2014, Nick Hilliard wrote:

> FB, T-mobile and you are all using ipv6->ipv4 protocol translators because
> ipv6-only services are not a viable alternative at the moment.

Using IPv6 internally is different from being able to use IPv6 end-to-end. 
6<->4 translators will be needed to reach the IPv4-only chunks of the 
Internet.  I don't think anyone is disputing that.  Traffic that can go 
IPv6 end-to-end can do so.

> The advantage that using ipv6 gives in these deployment scenarios is that
> it scales beyond the amount of address space available from rfc1918.  As a
> side effect, it also makes native end-to-end ipv6 connectivity pleasant.
> Sadly, ipv4 address availability continues to be necessary at the same run
> rate as before, except in situations where CGN is a possibility.

I think the expectation is that the utilization of those translators will 
plateau at some point, and then tail off as end-users go dual-stack or v6 
only.  Large/highly visible chunks of the Internet pushing IPv6 adoption 
helps get people toward the long-term goal of turning down those 
translators.  Eventually those remaining pockets of IPv4ness will have to 
sit behind 4<->6 translators to be able to speak with the rest of the 

CGN also comes with lots of downside that customers are likely to find 
unpleasant.  For some operators, customer (dis)satisfaction might be the 
driver that ultimately forces them to deploy IPv6.


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