Comprehensive interface status review: Which Cisco IOS command displays the configurable parameters and runtime statistics for all router interfaces (physical and logical)?
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Ashow running-config
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Bshow startup-config
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Cshow interfaces
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Dshow versions
Answer
Correct Answer: show interfaces
Explanation
Introduction / Context:Troubleshooting connectivity requires visibility into interface health and configuration. Cisco IOS provides several show commands, but only one gives a full, consolidated report of operational statistics, errors, encapsulation, bandwidth, duplex, and IP details for all interfaces.
Given Data / Assumptions:
- You need both configuration-related information and live counters in a single output.
- Multiple interface types may exist (Ethernet, Serial, Loopback, VLAN SVI).
- The goal is to examine status, not merely the saved or current config text.
Concept / Approach:
The command show interfaces prints per-interface blocks showing line protocol state, hardware address, MTU, BW, delay, reliability, load, encapsulation, input/output rate, errors, drops, and IP details. It is the broadest, statistics-rich view across all interfaces.
Step-by-Step Solution:
Enter privileged EXEC (Router#).Run: show interfacesOptionally filter: show interfaces | include errors | dropCorrelate with: show ip interface brief for concise up/down and addressing.Verification / Alternative check:
Compare with show running-config: it shows config lines but not live counters and errors. show interfaces provides packet statistics and error counters that confirm physical or data-link problems.
Why Other Options Are Wrong:
show running-config and show startup-config display configuration text only.
show versions is not a standard command; the common one is show version for software/hardware inventory, not per-interface stats.
Common Pitfalls:
Relying solely on show ip interface brief and missing duplex mismatches or CRC errors; overlooking interface resets and input errors that indicate cabling or speed/duplex issues.
Final Answer:
show interfaces