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CNX-001 · Question #73

What is the MOST likely cause of increased latency and packet retransmissions in a high- bandwidth, low-latency environment?

The correct answer is C. Duplex mismatch. A duplex mismatch occurs when one side of a link is configured for full-duplex and the other for half-duplex. The half-duplex side uses CSMA/CD and interprets simultaneous transmissions as collisions, triggering retransmissions and backoff timers. This creates significant latency

Cloud Network Operations and Troubleshooting

Question

What is the MOST likely cause of increased latency and packet retransmissions in a high- bandwidth, low-latency environment?

Options

  • AMTU fragmentation
  • BAsymmetric routing
  • CDuplex mismatch
  • DVLAN misconfiguration

How the community answered

(33 responses)
  • A
    6% (2)
  • B
    3% (1)
  • C
    82% (27)
  • D
    9% (3)

Explanation

A duplex mismatch occurs when one side of a link is configured for full-duplex and the other for half-duplex. The half-duplex side uses CSMA/CD and interprets simultaneous transmissions as collisions, triggering retransmissions and backoff timers. This creates significant latency and throughput degradation - especially noticeable in high-bandwidth environments where traffic is frequent. MTU fragmentation (A) causes overhead but is not the primary driver of retransmissions. Asymmetric routing (B) can cause issues but is less common in a single high-bandwidth link context. VLAN misconfiguration (D) would typically cause connectivity failures, not retransmissions.

Topics

#Network Troubleshooting#Duplex Mismatch#Packet Retransmissions#Latency

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