Which Fast Ethernet standard permits a maximum point-to-point segment length…
2012
Which Fast Ethernet standard permits a maximum point-to-point segment length of 2,000 metres under a full-duplex multimode-fibre configuration?
Answer: B. 100BASE-FX — ConceptA physical-layer Ethernet variant is identified by its data rate, signalling method, and medium-specific suffix. The permitted link length depends…
- A.
100BASE-TX
- B.
100BASE-FX
- C.
100BASE-T4
- D.
100BASE-T1
Attempted by 13 students.
Show answer & explanation
Correct answer: B
Concept
A physical-layer Ethernet variant is identified by its data rate, signalling method, and medium-specific suffix. The permitted link length depends mainly on the transmission medium and duplex configuration.
Copper Fast Ethernet variants are designed for short local links, whereas optical-fibre variants can support substantially longer point-to-point segments.
Application
Convert the stated distance: 2,000 metres = 2 kilometres.
Among the listed standards, 100BASE-FX is the optical-fibre Fast Ethernet variant. Over multimode fibre in full-duplex operation, its documented maximum segment length is 2 kilometres.
The 2-kilometre point-to-point segment length therefore corresponds to 100BASE-FX.
Cross-check and contrast
100BASE-TX uses two pairs of Category 5 twisted-pair copper and is associated with much shorter links.
100BASE-T4 uses four twisted pairs and was intended for legacy copper cabling rather than a 2-kilometre fibre span.
100BASE-T1 is a single-pair Ethernet family used for point-to-point automotive and industrial links, not this IEEE 802.3u fibre variant.
Result
Therefore, the required standard is 100BASE-FX.