Which of the following is the Formal IEEE Name and Speed for Fast Ethernet?

The correct choice for the Formal IEEE Name and Speed for Fast Ethernet is identified as 802.3u, which has a speed of 100 Mbps. Fast Ethernet is an extension of standard Ethernet that provides speeds of 100 Mbps, significantly increasing the network communication capability compared to the original Ethernet, which operates at 10 Mbps.

The designation IEEE 802.3u specifically refers to the standards established for Fast Ethernet technology, encompassing various physical media options such as twisted pair and fiber optics. This standard was introduced to enhance the standard Ethernet defined in 802.3, allowing for faster data transmission over the same infrastructure with better performance.

The other options reference different IEEE standards that correspond to different types of Ethernet. For instance, 802.3 refers to the original Ethernet specification with a maximum speed of 10 Mbps, while 802.3ab and 802.3z pertain to Gigabit Ethernet standards, which operate at 1000 Mbps (1 Gbps). Therefore, the primary reason why 802.3u is the correct answer is that it precisely defines the Fast Ethernet standard and its specified operational speed.