[dpe82]

By that logic, all fiber is "dark fiber". :)

As I recall, "dark fiber" came into use after the dotcom bust left lots of overbuilt and unused network infrastructure around that companies could buy up for years after for pennies on the dollar. Buying "dark fiber" in that context had meaning - it meant you were buying already built-out and unused fiber, compared to running your own fiber lines at full cost as had previously been more common.

[toast0]

Well, I was joking a bit, but I would consider it dark fiber when you lease the fiber and run the equipment on both ends, and lit fiber when the owner of the fiber is running the equipment on both ends and selling you IP transit.