Well, we don't really know enough about collaboration between tier1/2 and intelligence services, but I think it's reasonable to assume that any large network provider that has close financial ties to the US or NATO countries provides intel to the "NSA machine". I'm not sure about Russia and China (along with China-friendly neighbours). I would guess getting data is a high priority, and that NSA would go to great lengths to get taps in -- but what or how they do it I wouldn't know. Bribery and/or running a telco or two sounds reasonable given the (large) budgets, and mission statement(s).