Probably a dumb question, why the maximum size (and the one has most of packages) in the AMS-IX graph 1514 bytes instead of 1500 bytes that got discussed in the article?
If have a 1500 byte MTU for IP, then we need at least a 1514 byte MTU for IP + Ethernet. We often call the > 1514B MTU the "interface MTU". It's unnecessarily confusing.