Half-duplex vs full-duplex Ethernet Which statements are unique to half-duplex Ethernet when compared with full-duplex Ethernet?

Introduction / Context:
Ethernet links can operate in half-duplex or full-duplex. Understanding the operational differences explains why modern networks avoid hubs and prefer switches. Half-duplex inherited the original CSMA/CD model with collision handling, while full-duplex eliminates collisions and increases efficiency.

Given Data / Assumptions:

• Statements provided: (1) operates in a shared collision domain, (2) operates in a private collision domain, (3) has higher effective throughput, (4) has lower effective throughput.
• We compare half-duplex uniquely against full-duplex.

Concept / Approach:

Half-duplex means a device cannot transmit and receive simultaneously and must contend for the medium, creating a shared collision domain. Consequently, bandwidth is shared and effective throughput is lower than the nominal line rate. Full-duplex dedicates a switch port to a single device, creating a private, collision-free environment with higher throughput and no CSMA/CD.

Step-by-Step Solution:

Verification / Alternative check:

Throughput tests with identical hardware show fewer retransmissions and higher goodput in full-duplex due to elimination of collisions and backoff timers, confirming that half-duplex yields lower effective throughput.

Why Other Options Are Wrong:

• (2 only) misattributes full-duplex characteristics to half-duplex.
• (1,2 and 3) includes contradictory and incorrect claims.
• (4 only) ignores the shared collision domain property.
• (1 and 3) incorrectly asserts higher throughput for half-duplex.

Common Pitfalls:

• Mismatched duplex settings between NIC and switch cause late collisions and poor performance.
• Assuming auto-negotiation always selects optimal duplex; verify with show interfaces.

Final Answer:

1 and 4