>> Of course. We've been designing for co-existence since 1994, despite using the word "transition". It's all my fault (RFC1671). I prefer co-existence because we cannot wake up in the morning and find IPv4 disappeared completely, it will exist for a long period of time. But we need a co-existence solution that required no user intervention, rather by training or keeping calling for migration. Khaled Omar -----Original Message----- From: ietf [mailto:ietf-bounces@xxxxxxxx] On Behalf Of Brian E Carpenter Sent: Thursday, September 9, 2021 10:54 PM To: John Levine <johnl@xxxxxxxxx>; ietf@xxxxxxxx Cc: rg+ietf@xxxxxxxxxxxxxxxxx Subject: Re: the same old IPv6 argument, What's going on with the IETF. On 10-Sep-21 05:38, John Levine wrote: ... > But anyone who imagines that the public Internet will stop running on > IPv4 anytime soon, is nuts. Of course. We've been designing for co-existence since 1994, despite using the word "transition". It's all my fault (RFC1671). The OP is correct that IPv4 is at end of life in terms of expansion. (If anyone is interested in a quirky view of the numbers, see https://www.cs.auckland.ac.nz/~brian/sqlaw-revisited-published) Regards Brian