CompTIA Network+ (N10-009)Network ImplementationHard
A network technician is installing a new fiber optic cable run between two buildings located 400 meters apart. The connection needs to support 10 Gigabit Ethernet. The technician has several fiber cable types available. Which of the following fiber optic cable types is the most appropriate choice for this specific distance and bandwidth requirement?
- AMultimode fiber (OM1)
- BSingle-mode fiber (OS2)
- CPlastic Optical Fiber (POF)
- DMultimode fiber (OM3)
Show answer & explanationAnswer & explanation
Correct answer: D. Multimode fiber (OM3)
OM3 multimode fiber is specifically designed for 10 Gigabit Ethernet over distances up to 300 meters, and often slightly further depending on transceivers. While OS2 single-mode fiber can go much further, OM3 is a cost-effective and appropriate choice for 10GbE at 400 meters before needing to jump to single-mode.
Why the other options are wrong
- A. OM1 multimode fiber is typically limited to 10 Gigabit Ethernet at much shorter distances (e.g., 33 meters) and is not suitable for 400 meters.
- B. OS2 single-mode fiber supports 10 Gigabit Ethernet and much higher speeds over extremely long distances (kilometers), but it is generally more expensive to deploy than multimode for distances where multimode is sufficient.
- C. Plastic Optical Fiber (POF) is typically used for very short distances and low bandwidth applications, not 10 Gigabit Ethernet over 400 meters.
Fiber Optic Cable Types (OM1, OM2, OM3, OM4, OS1, OS2)
Different classifications of fiber optic cables distinguished by core diameter, light source, bandwidth, and maximum distance capabilities for various Ethernet speeds.
- Multimode (OM) uses LEDs or VCSELs, multiple light paths, shorter distances.
- Single-mode (OS) uses lasers, single light path, longer distances.
- OM3/OM4 are 'laser-optimized' multimode for higher speeds (10GbE+) over longer multimode distances.
Memory trick: Think of fiber types like car lanes: Multimode has many lanes (light paths) but gets congested faster. Single-mode has one super-fast lane for long hauls.