On Mon, Jun 11, 2018 at 6:29 PM Job Snijders <job@instituut.net> wrote:
I suspect that this may not be an apples to apples comparison.
Perhaps lack of IPv6 is more prevalent in rural areas with poorer connectivity to the rest of the Internet? Perhaps both these CDNs serve content for different types of devices over the different AFIs (maybe old mediaboxes with a slow cpu prefer IPv4?). Perhaps networks that deploy IPv6 are more likely to allow and accommodate on-net caches?
I theorize that the described speed difference between IPv4 and IPv6 is an artifact of how the data is analysed rather than an architectural speed difference between the protocols themselves.
Besides the data bias that could indeed exist, I noticed many deployed traffic shapers not supporting IPV6, and imagine that some traffic engineering is currently being focused on IPv4 traffic. So even the protocol themselves having comparable performance, IPv6 bandwidth could be smoother than IPv4 bandwidth for some users. Perhaps instead of looking at global averages, we could look at speed comparison for dual-stacked users, like in how many of them see better or worse performance with v4/v6. Rubens