Which IEEE standard describes various Ethernet technologies?

The IEEE 802.3 standard specifically addresses various Ethernet technologies, defining the physical and data link layer specifications for wired Ethernet networks. It encompasses the specifications for several Ethernet types, including traditional 10BASE-T, 100BASE-TX, and more modern standards like 1000BASE-T and 10GBASE-T. This standard plays a crucial role in ensuring interoperability between different Ethernet devices, which is vital for network communication.

In the context of the other choices, the 802.1 standard focuses on network management and architecture, particularly in relation to bridging and network layer protocols. The 802.2 standard supports logical link control for networks but does not specifically pertain to Ethernet technologies. The 802.5 standard relates to Token Ring networks, which are distinct from Ethernet. Therefore, the unique focus of 802.3 on Ethernet technologies makes it the correct choice.