Which protocol is primarily supported by the third layer of the Open Systems Interconnection reference model?

HTTP operates at Layer 7 (Application) and TLS operates at Layer 5/6 (Session/Presentation), both far above Layer 3.

IPv4 and IPv6 operate at OSI Layer 3, the Network layer, which is responsible for logical addressing, routing, and path determination across interconnected networks. IP provides the source and destination addressing that routers use to forward packets between different network segments, which is the core function of Layer 3.

TCP and UDP are Transport layer protocols operating at OSI Layer 4, providing end-to-end communication and port-based multiplexing.

ATM is a Layer 2 (Data Link) technology and MPLS is commonly described as Layer 2.5, operating between the Data Link and Network layers, not as a primary Layer 3 protocol.