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CCNA Exam - Question 829


A technician receives a report of network slowness and the issue has been isolated to the interface FastEthemet0/13. What is the root cause of the issue?

FastEthernet0/13 is up, line protocol is up

Hardware is Fast Ethernet, address is 0001.4d27.66cd (bia 0001.4d27.66cd)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 250/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set -

Auto-duplex (Full) Auto Speed (100), 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input 18:52:43, output 00:00:01, output hang never

Last clearing of “show interface” counters never

Queueing strategy: fifo -

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 12000 bits/sec, 6 packets/sec

5 minute output rate 24000 bits/sec, 6 packets/sec

14488019 packets input, 2434163609 bytes

Received 345348 broadcasts, 0 runts, 0 giants, 0 throttles

261028 input errors, 259429 CRC, 1599 frame, 0 overrun, 0 ignored

0 watchdog, 84207 multicast

0 input packets with dribble condition detected

19658279 packets output, 3529106068 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Show Answer
Correct Answer: C

The root cause of the network slowness related to the interface FastEthernet0/13 is indicated by the presence of physical errors. Specifically, the high number of input errors (261,028) and CRC errors (259,429) suggests a physical layer issue, such as a bad cable, faulty NIC, or poorly connected interface. These types of errors often lead to network performance degradation, which aligns with the reported network slowness.

Discussion

4 comments
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kncappyOption: C
Dec 23, 2023

A high number of CRCs typically result from collisions but can also indicate a physical issue (cabling, bad interface/NIC)

[Removed]
Jun 10, 2024

Reasons for Bad Frames and CRC Errors Some of the reasons when you get bad frames and CRC errors can be: Bad physical connection; transceiver, copper, fiber, adapter, port expander, and so on. MTU Violation Received bad CRC stomped from neighboring cut-through switch. https://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-infrastructure-ucs-manager-software/215449-commands-for-troubleshooting-connectivit.html

Yannik123Option: C
Nov 13, 2023

Look on CRC

HSong
Nov 2, 2023

reliability 250/255,

[Removed]Option: C
Sep 30, 2024

C is correct (high) input errors, (high) CRC, (high) frame errors = phisical issue

SeMo0o0o0o0
Jan 28, 2025

physical* sorry :)