Ethernet Over Ethernet
It's called Ethernet over Ethernet (EOE), and it's a proprietary alternative to Mac-in-Mac. KDDI made that choice about seven years ago.
"We used to use regular Mac-in-Mac and that didn't work out right," said Taichi "Todd" Okamoto, KDDI's manager of sales engineering for the western United States. "So we worked with another vendor and came up with a specific proprietary frame. Since then, it's been great."
It's true that Mac-in-Mac -- also known as Provider Backbone Bridging (PBB) -- is commonplace now, but we're talking about seven years ago, so KDDI's story seems understandable.
EOE is similar to Mac-in-Mac. KDDI encapsulates traffic under carrier MAC addresses for the backbone to read, which means fewer address numbers get used over the backbone.
EOE infuses some extras like a time-to-live parameter, which helps prevent loops from forming. KDDI filed no patents on this stuff, and Okamoto says he's seeing others adopt some of the ideas behind the technology, so it's possible that pieces of the proprietary EOE will find their way into standards after all.
— Craig Matsumoto, West Coast Editor, Light Reading