I don't understand the "didn't use the connection at all outside that time, they should be able to get some free bandwidth." How or why would Google shut down a data center for that long just to pump some data across the lines? Wouldn't that mean down time? I don't get it.
The purpose of this data transfer was internal - transferring search index data between west and east coast - and they had a supplier contract just for this purpose.
They probably had a separate line coming into a router specifically for that purpose and directed all of the traffic to transfer the data through this router.
