CCNA Network Infrastructure and Connectivity Practice Test 18 — 15 Questions

Question 1

Drag and drop the following steps into the correct order to configure a new WLAN on a Cisco WLC using IOS-XE CLI, including WPA3-Personal security, and to complete a wireless client association with DHCP.

Accepted Answer

Enter global configuration mode, create WLAN profile, configure WPA3-Personal (SAE) security, enable WLAN, client associates, client obtains IP via DHCP.. The configuration order follows the Cisco IOS-XE WLC CLI: first enter global config, create the WLAN profile, set security (WPA3-Personal/SAE), enable the WLAN, then the client associates and gets an IP via DHCP.

Answer

Enter global configuration mode, create WLAN profile, enable WLAN, configure WPA3-Personal (SAE) security, client associates, client obtains IP via DHCP.

Answer

Enter global configuration mode, configure WPA3-Personal (SAE) security, create WLAN profile, enable WLAN, client associates, client obtains IP via DHCP.

Answer

Enter global configuration mode, create WLAN profile, configure WPA3-Personal (SAE) security, enable WLAN, client obtains IP via DHCP, client associates.

Question 2

Drag and drop the following steps into the correct order to configure WPA3-Personal on a WLC, associate a wireless client, and complete the 802.11 authentication and DHCP process.

Accepted Answer

Configure WLAN with WPA3-Personal on WLC, then associate client, then client obtains IP via DHCP, then client completes 802.11 authentication.. The correct order is to first configure the WLAN with WPA3-Personal on the WLC, then the client completes 802.11 authentication (open system authentication followed by the SAE handshake), next the client associates with the AP, and finally the client obtains an IP address via DHCP. Option B correctly follows this sequence, while option A incorrectly reverses authentication and association, option C places WLAN configuration after client association, and option D erroneously performs DHCP before any wireless steps.

Question 3

Which TWO statements correctly compare 802.11ac and 802.11ax features?

Accepted Answer

802.11ax uses OFDMA, while 802.11ac uses OFDM.. Option A is correct because 802.11ax (Wi‑Fi 6) introduces Orthogonal Frequency Division Multiple Access (OFDMA), which allows multiple users to share subcarriers simultaneously, improving efficiency in dense environments. In contrast, 802.11ac (Wi‑Fi 5) uses Orthogonal Frequency Division Multiplexing (OFDM), where each transmission occupies the entire channel for a single user, leading to less efficient channel utilization. Option C is correct: WPA3 is mandatory for Wi‑Fi 6 (802.11ax) certification, while for 802.11ac it is optional—devices can still obtain Wi‑Fi 5 certification with WPA2 only. Option B is incorrect because 802.11ac supports a maximum of 256‑QAM; 1024‑QAM is first introduced with 802.11ax. Option D is wrong: 802.11ac operates exclusively in the 5 GHz band, but 802.11ax operates in both 2.4 GHz and 5 GHz. Option E is false: both standards support 20, 40, 80, and 160 MHz channel widths; 802.11ac does not exclusively use 80 MHz, and 802.11ax does not use 160 MHz exclusively.

Answer

Both 802.11ac and 802.11ax support 1024-QAM modulation.

Answer

Both standards use only the 5 GHz band.

Answer

802.11ac uses 80 MHz channels, while 802.11ax uses 160 MHz channels exclusively.

Question 4

Drag and drop the 802.11 standards on the left to their correct frequency band and maximum throughput on the right.

Accepted Answer

802.11b: 2.4 GHz, 11 Mbps. Each 802.11 standard operates in specific frequency bands and has a maximum theoretical throughput. 802.11a uses 5 GHz at 54 Mbps, 802.11b uses 2.4 GHz at 11 Mbps, 802.11g uses 2.4 GHz at 54 Mbps, 802.11n uses both 2.4 and 5 GHz up to 600 Mbps, 802.11ac uses 5 GHz up to 6.9 Gbps, and 802.11ax uses 2.4, 5, and 6 GHz up to 9.6 Gbps.

Question 5

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue. Use the OSI bottom-up method, starting with the lowest layer and moving up.

Accepted Answer

Check physical cabling and link lights, then verify IP configuration, then test application connectivity.. The bottom-up approach starts at Layer 1 and moves up to Layer 7, checking physical, network, and application layers in order.

Question 6

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method.

Accepted Answer

Check physical connectivity (cables, link lights). The bottom-up approach starts at Layer 1 (physical connectivity), then moves to Layer 3 (IP configuration and gateway ping), and finally to Layer 7 (DNS resolution). No Layer 2 step is included in these steps. Verifying IP configuration, such as DHCP and subnet mask, is a Layer 3 activity, not Layer 2. This method ensures systematic isolation of the problem from the physical layer upward.

Question 7

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method.

Accepted Answer

Check physical connectivity (cables, link lights). The OSI bottom-up method starts at Layer 1 (physical) and moves upward. Step A (Check physical connectivity) verifies cables and link lights at Layer 1. Step D (Check for MAC address table entries) examines Layer 2 connectivity. Step B (Verify IP address configuration) confirms Layer 3 settings. Step C (Test application functionality) tests Layer 7 applications such as ping or web browsing. This sequence aligns with the bottom-up approach of resolving lower-layer issues before examining higher layers.

Question 8

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method.

Accepted Answer

Check physical connectivity, then data link, then network, then transport, then application. The OSI bottom-up method starts at physical layer and moves up. This ensures that lower-layer issues are resolved before higher-layer troubleshooting, preventing wasted effort on symptoms caused by underlying problems.

Answer

Check application, then transport, then network, then data link, then physical

Answer

Check network, then data link, then physical, then transport, then application

Answer

Check physical, then network, then data link, then transport, then application

Question 9

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method.

Accepted Answer

Check the physical cable connections and link lights. The OSI bottom-up troubleshooting method starts at Layer 1: first check physical cable connections and link lights (A). Next, at Layer 2, verify the switch's MAC address table (D) to ensure local segment communication is intact. Moving to Layer 3, confirm the IP address configuration and subnet mask (B) are correct. Finally, ping the default gateway (C) to validate end-to-end Layer 3 connectivity. The correct sequence is A → D → B → C, because each lower layer must function before higher-layer tests can succeed.

Question 10

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method. The client cannot access a web server by its FQDN.

Accepted Answer

Check physical connectivity (cables, link lights, interface status).. The bottom-up OSI approach starts with Layer 1 (physical) – step A; then Layer 2 (data link) – step D; then Layer 3 (network) – step C; and finally Layer 7 (application) – step B. This methodical progression isolates the issue layer by layer, ensuring all dependencies are checked systematically.

Question 11

Drag and drop the following troubleshooting steps into the correct order to diagnose a client connectivity issue using the OSI bottom-up method. The client is unable to access a web server by its FQDN.

Accepted Answer

Check physical connectivity, then verify link status, then check IP configuration, then test DNS resolution, then attempt HTTP access.. The OSI bottom-up approach starts at Layer 1 (physical), then Layer 2 (data link), Layer 3 (network), and finally Layer 7 (application) for DNS/FQDN resolution. The given sequence follows this principle by checking physical connectivity and link status before IP configuration, then testing DNS and HTTP access.

Question 12

Drag and drop the following troubleshooting steps into the correct order to diagnose client connectivity using the OSI bottom-up method.

Accepted Answer

Check physical cabling and link lights. Following the OSI bottom-up model, we begin with Layer 1 physical connectivity (cabling and link lights), then Layer 2 data link (VLAN and switchport configuration), Layer 3 network (IP configuration and default gateway), and finally Layer 7 application (DNS resolution and application settings).

Question 13

Which TWO tools or commands are commonly used to troubleshoot wireless client connectivity issues on a Cisco WLAN?

Accepted Answer

ping. The ping command (A) tests basic IP-layer connectivity from the wireless client to a target host, revealing whether the client has a valid IP and can reach the default gateway or servers. The show wireless client summary command (E) is a standard WLC diagnostic command that displays associated clients’ MAC addresses, IP addresses, VLAN assignments, and authentication states, enabling quick identification of connectivity issues at the wireless link layer. Option B, ipconfig /release, only renews the client’s DHCP lease and does not diagnose ongoing connectivity. Option C, traceroute, traces the path to a destination, which is not a primary wireless client troubleshooting tool; it is more suited for routing analysis. Option D, show running-config, displays the device’s static configuration, not live client connectivity. Option F, debug dhcp detail, is a high-impact debug that is too granular for general wireless troubleshooting and can disrupt service.

Answer

ipconfig /release

Answer

traceroute

Answer

show running-config

Answer

debug dhcp detail

Question 14

You are connected to R1. The connection between R1 and R2 is experiencing intermittent failures. Troubleshoot the interface G0/0 on R1 to identify and resolve the issue so that the link becomes stable and operational.

Accepted Answer

Enter interface configuration mode for G0/0 and issue the 'no loopback' command.. The interface shows '(looped)' in the line status, indicating a layer 1 loop (likely a cable loopback) or a misconfigured loopback test. The interface is physically up and line protocol is up, but the loop condition prevents normal data flow. To fix this, you must remove the loopback test with 'no loopback' on the interface, then verify the interface recovers to 'up, line protocol is up' without the loop indication.

Answer

Enter interface configuration mode for G0/0 and issue the 'no shutdown' command.

Answer

Enter interface configuration mode for G0/0 and issue the 'speed 100' command to force 100 Mbps.

Answer

Enter interface configuration mode for G0/0 and issue the 'no keepalive' command.

Question 15

You are connected to R1. The link between R1 and R2 is experiencing intermittent connectivity and poor performance. Review the provided show interface output to identify the root cause(s) of the issue, then apply the necessary configuration changes to resolve the problem and restore full connectivity.

Output from R1:
```
GigabitEthernet0/0 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is aaaa.bbbb.cccc (bia aaaa.bbbb.cccc)
  Internet address is 192.168.1.1/30
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Half-duplex, 100Mb/s, link type is auto, media type is RJ45
  output flow-control is unsupported, input flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output 00:00:01, output hang never
  Last clearing of "show interface" counters 00:01:23
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     150 packets input, 1500 bytes, 0 no buffer
     Received 0 broadcasts (0 multicasts)
     0 runts, 0 giants, 0 throttles
     150 input errors, 150 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     200 packets output, 2000 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out
```

Accepted Answer

Configure the interface with 'speed 1000' and 'duplex full' to match R2's settings, then clear counters.. The show interface output reveals that R1's GigabitEthernet0/0 is operating at half-duplex, 100 Mb/s, yet it is accumulating a high number of CRC errors (150 in 1 minute 23 seconds). This indicates a speed/duplex mismatch with R2, which is likely set to full-duplex at 1000 Mb/s. To resolve, you must manually configure R1 to match R2's proper settings by issuing the 'speed 1000' and 'duplex full' commands, then clearing the counters to start fresh monitoring. The other options are incorrect because they do not address the mismatch: replacing the cable would not fix a configuration issue; disabling autonegotiation alone may not fix the mismatch if the hard-coded values are still wrong; and increasing the MTU does not affect CRC errors caused by duplex mismatch.

Answer

Replace the faulty cable between R1 and R2 to eliminate CRC errors caused by physical layer issues.

Answer

Disable autonegotiation on the interface with 'no negotiation auto' to force the link to use the configured speed and duplex.

Answer

Increase the interface MTU to reduce fragmentation and improve performance on the link.