Cisco Certified Network Associate (CCNA) Practice Exam

What type of cabling does the 100BASE-FX standard use, and what is its maximum length?

1. Single-mode fiber, 10 km

2. Two strands, multimode, 400 meters

3. Long-wavelength laser, 3 km

4. Copper cabling, 100 meters

The correct answer is: Two strands, multimode, 400 meters

The 100BASE-FX standard utilizes multimode fiber optic cabling, specifically designed to support Ethernet networking at 100 Mbps over fiber. This standard uses two strands of multimode fiber for full-duplex communication, allowing simultaneous sending and receiving of data. The maximum distance for 100BASE-FX over multimode fiber is up to 400 meters, making it suitable for relatively short-distance connections compared to its single-mode counterparts. The nature of multimode fiber allows it to carry multiple light signals simultaneously, which is ideal for local area networks where high bandwidth and distances under 400 meters are common. This capability is critical for maintaining the integrity and speed of data transmission over short distances often found in building networks. In contrast, the other options refer to cabling types and specifications that do not align with 100BASE-FX. Single-mode fiber operates differently and supports longer distances, while copper cabling generally has a much shorter maximum length for Ethernet standards than what is specified in the context of 100BASE-FX. Long-wavelength lasers and their distances, while applicable to other standards, do not suit the multimode specification of 100BASE-FX.