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Zorluk: KolayInterface and Cable Troubleshooting Issues

A network technician observes high counts of late collisions and Frame Check Sequence (FCS) errors on a switch interface connected to a server. A CLI check shows the interface output below:

text
FastEthernet0/1 is up, line protocol is up (connected)
Full-duplex, 100Mb/s, media type is 100BaseTX
542 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
1243 output errors, 891 late collisions

Which physical or data-link issue is the most likely cause of these interface error statistics?

  1. A duplex mismatch between the switch interface and the connected deviceCevap
  2. B
    Selecting an incorrect Ethernet cable pinout type for the connection
  3. C
    A mismatch between the native VLAN IDs configured on the interconnected interfaces
  4. D
    Misinterpretation of Layer 2 discovery neighbor information from CDP or LLDP messages

Cevap

A duplex mismatch between the switch interface and the connected device is the primary cause of late collisions and FCS errors.
A duplex mismatch occurs when one end of an Ethernet link operates in full-duplex while the opposite end operates in half-duplex. The full-duplex device transmits data whenever ready without checking for carrier activity. When the half-duplex device is transmitting and receives data from the full-duplex device after sending its initial 64 bytes, it records a late collision.

Adım Adım Çözüm

1
Analyze the interface error counters in the CLI output.
Identified high late collisions and output errors on an operational (up/up) link.
Late collisions occur when a collision is detected after the first 64 bytes (512 bits) of a frame have been transmitted.
2
Correlate late collision symptoms with duplex settings.
Determined that one end is operating in full-duplex while the remote end is operating in half-duplex.
The full-duplex end sends traffic without listening for carrier sense, causing the half-duplex end to transmit simultaneously and register late collisions.

Anahtar Kavram

Duplex Mismatch Symptoms and Interface Error Counters
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Konular

Interface and Cable Troubleshooting Issues

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