[happythought]

FANGs all use white box hardware with “merchant silicon” meaning they buy the chipsets directly from Broadcom, Mellanox, etc. and build their own devices. However, they do all have Broadcom and Mellanox in common and Cisco, juniper, and arista do too.

[nwlieb]

Some FANGs definitely use Arista/Cisco. As far as I know white box hardware is mostly for top of the rack switches (as opposed to backbone infra).

[packetslave]

Depends on which backbone infra :-) Take a look at the B4 and Jupiter papers from Google, for example.