IPv4 and IPv6 on the same domain vs. seperated domains

[ipv6network]

I would like to hear your opinion, whether you prefer IPv4 and IPv6 on the same domain (example.com) or on separate domains (example.com and ipv6.example.com)
I have collected a few points:

IPv4 and IPv6 on the same domain
Advantages:
* IPv6 automatically in use for all users
Disadvantages:
* Possibly problems when the operating system / browser already supports IPv6 and then calls the Web site with IPv6, but there is no IPv6-Route/-Tunnel to the destination host

IPv4 and IPv6 on separate domains
Advantages:
* Only those people use IPv6, which also know how to use IPv6
* Technical problems largely avoidable
Disadvantages:
* IPv6 not automatically in use for all visitors

What do you think?

Simon

[cholzhauer]

Like I mentioned on Go6

You've pretty much hit the nail on the head. Google didn't list AAAA records for their stuff because they didn't want the users to see a difference in their experience.

Unless you have native IPv6 connectivity, you're going to see a performance loss when using a tunnel. (unless you live really close to your tunnel endpoint)

[jimb]

The performance hit with a 6in4 tunnel isn't really that bad.  I've found HE to be pretty fast, although I think my ISP peers with HE (five hops away), and the ping times are pretty quick (avg 8.5ms RTT for me.  the POP I use is about 10 miles away).

The big problem for Google, et al, was problems from 6to4 and Teredo users, which does have lots of performance issues that vary.  For instance, on a few of my friends ISPs, the 6to4 anycast address went to Sweden (this is from Canada and LA).

I think Windows automatically does 6to4 if one of the NICs has a public address (not sure about this), and Teredo otherwise.  But in the case of Teredo, I've found most software doesn't use it anyway, since it needs to have a flag set saying to use it.

For right now I'd probably stick to separate domains.  Today's IPv6 users are tech savvy enough to enter an IPv6 URL.  You could also easily add a link to click on, for the IPv6 version of the site.  In the future, it won't be hard to simply add the IPv6 address to your standard address, once IPv6 becomes more prevalent.

[cholzhauer]

The performance hit with a 6in4 tunnel isn't really that bad.  I've found HE to be pretty fast, although I think my ISP peers with HE (five hops away), and the ping times are pretty quick (avg 8.5ms RTT for me.  the POP I use is about 10 miles away).

My POP is in Chicago and I'm 240 miles away ;)

[snarked]

Everything I run on my servers is dual-stacked anyway, so I have both IPv4 and IPv6 addresses on the same DNS labels.  I do not recognize such as having any disadvantages where a properly constructed client is concerned (one that tries ALL addresses should one not respond).

I'm 3 miles and <5ms from my nearest tunnel endpoint.  My other tunnel is on a different continent (in order to be near certain clients, thus <10ms from them).  I also have a native IPv6 assignment but the hardware to support that is currently down for repair/replacement.

[jimb]

The problem isn't properly constructed clients.   :P