Interface and cable issues: collisions, errors, duplex mismatch, speed mismatch, and basic fault indicators

By the end you’ll be able to

• Explain why collisions are associated with half-duplex Ethernet operation and why they should not be expected on correctly operating full-duplex switched links.
• Interpret common interface error indicators such as CRC errors, input errors, runts, giants, late collisions, and drops at a foundational troubleshooting level.