The technology is sometimes called Audio Over EtherNet. There are several incompatible proprietary protocols from several manufacturers - EtherSound, CobraNet, A-Net, DANTE (more at wikipedia), but a proper Ethernet standard is being introduced called IEEE 802.1 AVB (Audio Video Bridging).
AVB is a combination of several extensions to ethernet protocols, designed to be usable for many purposes, but professional audio multicore replacement is the main driving force behind the standards at the moment. Because these standards are being designed by the same people as IEEE itself, and are designed to be usable in a range of situations, I expect that future networking gear (switches, routers etc.) will support them as standard, and the price will fall rapidly. I would not consider a non-AVB system - you'll be locked in to something that won't exist for very long.
The AVB standard is being promoted by the industry group AVnu.