It's interesting that this is now the insurgent, because in some sense, this looks like networking done the old way, the telco way: centralised provisioning, aiming for 100% utilisation, etc. The kind of thing that cisco et all were originally the small rebels against.
I was thinking the exact same thing. Google controls their own network, so they can implement a centrally-managed, circuit-based networking scheme.
Telephone networks tend to use these (on a scheme called SS7[1]) because in most countries, the telephone networks were built by monopolies. It was possible to develop the entire network as a single system and thus to obtain very high efficiencies for certain use cases.
Google goes a step further. What they seem to have done is married circuit-based networking with batch planning. The network itself is circuit based -- rather than each packet "finding" its own way, it can be routed end-to-end by a central plan. But the decision of what to move when can also be planned. Note the reference to "simulating a load". That's similar to what mainframe batch planning achieves.
