The IEEE AVB/TSN standards define how a network (primarily Ethernet networks) should be made timing-aware. AVB/TSN are not communications protocols, but – like other capabilities such as VLAN and Power over Ethernet – they are core network capabilities that can be used by any (open or proprietary) communications system that needs them. When you buy an Ethernet chip, it just has this capability.
These foundational standards facilitate a broad-range of higher-layer communications technologies, all in a timing-aware environment. So the user can still choose the most appropriate transport layer, data encapsulation format and enumeration and discovery techniques for their application, all within a timing-aware framework.