A network administrator is analyzing Cisco IOS switch interface outputs to resolve network degradation. Match each interface status combination or error counter condition on the left to its corresponding primary root cause on the right.
- Interface state: FastEthernet0/1 is up, line protocol is downLayer 2 encapsulation mismatch, keepalive failure, or missing clocking/framing from the connected peer
- Interface state: FastEthernet0/2 is administratively down, line protocol is downThe interface has been manually disabled in software using the shutdown configuration command
- Interface statistics: High count of late collisions on an interface operating in full-duplexDuplex mismatch where the local end is set to full-duplex while the far-end device operates in half-duplex
- Interface statistics: Increasing count of runts accompanied by CRC errorsPhysical cable noise, EMI, or collision fragments causing damaged frames smaller than 64 bytes
Cevap
FastEthernet0/1 up/down matches Layer 2 encapsulation mismatch, keepalive failure, or missing framing. FastEthernet0/2 administratively down matches interface manually disabled via the shutdown command. High count of late collisions matches a duplex mismatch with local full-duplex and remote half-duplex. Increasing runts with CRC errors matches physical cable noise, EMI, or collision fragments creating sub-64 byte frames.
Each interface state and counter statistic accurately aligns with its underlying physical or data-link layer cause: 'up/down' denotes Layer 2 framing/keepalive failure, 'administratively down' represents a software shutdown command, late collisions stem from a duplex mismatch between full-duplex and half-duplex endpoints, and runts with CRC errors signify frame corruption under 64 bytes due to physical noise or collisions.
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Anahtar Kavram
Cisco IOS interface status states and error counter interpretation