The private side of the network is a secret, but a recent disclosure from Google[90] indicate that they use custom built high-radix switch-routers (with a capacity of 128 × 10 Gigabit Ethernet port) for the wide area network. Running no less than two routers per datacenter (for redundancy) we can conclude that the Google network scales in the terabit per second range (with two fully loaded routers the bi-sectional bandwidth amount to 1,280 Gbit/s).
As I said it’s 100 times more advanced than that.
They can switch IPs, datacenters, regions, whatever they want. They even have access to BGP routing.
They also use some custom switches according to Wikipedia: