What network does Coinbase use for ETH?

Could you please elaborate on the network that Coinbase utilizes for Ethereum (ETH) transactions? I'm particularly interested in understanding the underlying infrastructure that powers these transactions and how it ensures security and efficiency. Is it based on the Ethereum mainnet, or does Coinbase have its own proprietary network? Additionally, what are the key factors Coinbase considers in choosing this network, and how does it compare to other available options in the cryptocurrency industry? I'm curious to gain a deeper understanding of the technical underpinnings that drive this popular cryptocurrency exchange.