Cisco Certified Network Associate (CCNA) Practice Exam

What is the maximum distance of a 1000BASE-LX connection using multimode fiber?

1. 3 km

2. 10 km

3. 220 m

4. 400 m

The correct answer is: 3 km

The maximum distance for a 1000BASE-LX connection using multimode fiber is indeed defined in terms of its specifications. However, it is important to point out that 1000BASE-LX is primarily intended for use with single-mode fiber, which allows for longer distances, typically up to 10 kilometers or more. When using multimode fiber, the effective range is limited. Although multimode fiber connections can extend up to 850 nm, the maximum distance typically achieved for 1000BASE-LX with multimode fiber is around 550 meters under ideal conditions. This differs significantly from the values provided in the choices. Therefore, the longest possible distance for a 1000BASE-LX connection on multimode fiber does not match the value indicated; in fact, the actual typical distance does not exceed a few hundred meters. Knowing this helps clarify the confusion around the specifications for multimode versus single-mode fiber connections. In summary, while the maximum distance for multimode fiber in the context of 1000BASE technology is significantly shorter than the options suggest, the most common and realistic distance with multimode fiber is around 400 meters and not 3 km as previously selected.