[rumdz]

That makes sense. I'm very curious about real-world studies. As a gamer, I'm especially interested in the affect ipv6 has on UDP for real time gaming applications. That's an area where even 5ms can have an enormous affect on the experience.

[tsimionescu]

That's a very interesting case, as UDP is very reliant on MTU. If the IPv6 headers take out more space from the ethernet frame, that leaves less space for the UDP payload. Which means that a UDP payload which was at the limit for IPv4 on the typical MTU needs to be fragmented into two IPv6 packets, which will likely increase latency quite significantly.

However, this will depend on each specific game, if they are using all the available space or not. If they're sending 200 byte datagrams, they shouldn't see any difference.

On the flipside, IPv6 has a larger minimum MTU than IPv4, so it could happen that your maximum UDP payload actually goes up when switching to IPv6. So, if the game previously had to send 5 packets to do an update, it might be able to send only 3 when it can rely on IPv6, so maybe latency actually significantly improves.

[IcePic]

If you try "ping" and "ping6" towards a multi-protocol host, you see both send 64 bytes each, so while v6 source and destination addresses take up lots of extra space, the v6 IP packets have less of the "this part could be useful for tcp" which means icmp pings can be of the same size, even though the two addresses eat up lots more bytes.

Not sure if the same goes for game UDP packets, but the optional header stuff in v6 IP packets means more of it goes to the useful parts of the payload and less to "the sum of all protocol bits and flags that is not used by all traffic".

[jabiko]

If you look at Googles IPv6 statistics the latency seems to be lower with IPv6 in almost all countries: https://www.google.com/intl/de/ipv6/statistics.html#tab=per-...