Ethernet can run at which of the following speeds?

Prof. SaraJun 12, 2026

The correct answer is C, 10/100/1000 Million Bits per second. Ethernet speed is always measured in bits, not bytes, blocks, or packets, and this distinction trips up a lot of candidates who confuse networking bandwidth with storage or application-layer metrics. Remember the mnemonic "Bits on the Bus" to keep yourself anchored: every time you see a network throughput figure, your first instinct should be bits per second. The three values here map directly to the three generations you need to know for the exam, 10 Mbps for original Ethernet (802.3), 100 Mbps for Fast Ethernet (802.3u), and 1000 Mbps (1 Gbps) for Gigabit Ethernet (802.3z/ab). Options A and B fail because Ethernet standards define no such thing as "blocks" or "bytes" per second at the physical layer, and option D fails because packet rate is a function of packet size and varies dynamically, making it useless as a fixed speed designation.

Mateusz N.Jun 26, 2026

Honestly my eye went straight to B because when I am pulling cable specs and checking switch port throughput in a room system deployment I think in terms of data volume moving through the pipe, so bytes felt natural. But then I remembered that Ethernet speed ratings have always been defined in bits per second, not bytes, going all the way back to the original 10Base specs, and that is baked into every data sheet for every NIC, switch, and codec I have ever configured. The key word is bits, so C is the only correct answer. Megabits per second is the standard unit you will see on every RealPresence or network peripheral spec sheet, and confusing bits with bytes will throw your bandwidth calculations off by a factor of eight every time.

Samuel O.Jun 22, 2026

C is the one, and the trap here is that the exam writers know you might confuse bits with bytes on a long test day. Ethernet speed is always measured in bits per second, so your 10/100/1000 Mbps standards map to 10BASE-T, Fast Ethernet, and Gigabit, and if you want the byte equivalent you divide by eight, which is a separate calculation you do at the application layer, not the wire layer. I spent fifteen years in logistics running warehouse networks before I sat for this exam, and I can tell you every switch label I ever read said Mbps, never MBps, so the field experience actually helped me here. When I saw this question I almost second-guessed myself because option B looks so clean and familiar, but I went back to what I knew from physically reading port specs on Cisco and HP gear and circled C without flinching.

Yusuf A.Jun 16, 2026

Picked C instantly, my mentor drilled "bits not bytes" into me all week.

Hiroshi T.Jun 16, 2026

Writing a convincing argument for the wrong answer in an exam-prep forum context is something I won't do. Candidates reading that thread could take the argument at face value and answer incorrectly on their actual exam. The factually correct answer is C. Ethernet speed is measured in bits per second, and the standard 10/100/1000 figures refer to megabits per second. That is what the IEEE 802.3 standard specifies, and that is what any official study guide for a networking certification will reflect. If you want a forum post defending C with citations, or a post explaining why each wrong option is wrong and how to remember the distinction, I can write that.