[AusNOG] Prediction: Google et. al. may artificially penalise IPv4 clients

[Mark Newton]

Allow me put a few word into Geoff’s mouth to summarize his comment:
“IPv6 in operation is no worse than IPv4.”

There are some features of IPv6 which would be very nice to have, which don’t work very well, such as the promise of larger MSSs. They’ve under-delivered, but the bits that work well are no worse than IPv4.

In the same way that IPv4 needs PMTU caches on hosts to run effectively, IPv6 needs MSS caches, which are generally enabled by default, so meh.

And like IPv4, you need to make sure that your routing isn’t broken. Huge news.

I know the purists hate it (and I’m not counting Geoff as a purist in this regard), but: If you treat it like IPv4 with big addresses, it works just fine.

Despite the good intentions of the IETF and associated organizations, I suspect IPv6’s long term future is, indeed, to be IPv4 with big addresses. Yes, it could be so much more. But it isn’t, and it doesn’t need to be, so get over it and get on with it.

Regards,

  - mark


> On May 2, 2017, at 9:37 AM, Geoff Huston <gih at apnic.net> wrote:
> 
> 
>> On 2 May 2017, at 8:20 am, Tim Raphael <raphael.timothy at gmail.com> wrote:
>> 
>> Given it’s been a while since our last discussion… what are the remaining roadblocks for ISPs taking up v6?
>> 
>> Lack of funds is not a valid point.
>> 
>> - Tim
>> 
> 
> You asked.
> 
> IPv6 Packet Fragmentation handling is broken. 
> 
> Equally, IPv6 Extension Header handling is a mess. 
> 
> SLAAC and RDNSS and DHCP6 is a chaotic mess.
> 
> Routing coverage is erratic. 
> 
> As long as you treat IPv6 kindly, use very small TCP MSS values, avoid UDP, pay care in delivering all ICMPv6 messages, run host MSS caches af necessary, and be ultra careful about routing both in terms of the completeness of the routes you see and the extent to which your routes get propagated then IPv6 will likely work just fine once you’ve got past the auto-config stage. But push it harder in any of these areas and you'll regret it.
> 
> So I suspect for many folk it requires a level of loving care and technical attention that they are not willing or able to expend right now. I can well understand that, and I’m not willing to castigate anyone for still being cautious. Whether you deploy IPv6 today or tomorrow you can’t stop the ongoing task of cramming more stuff into IPv4 just yet. So if your engineering and tech assistance resources are limited, I can readily understand anyone who is still waiting just a bit longer. With a bit of luck we'll find solid ways to avoid these issues in the coming months and the entire task will then be a lot less forbidding than it is now. Or we won’t. Can't tell yet.
> 
> Geoff
> 
> 
> 
> 
>