Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
AP-22 status: - Ethernet link: up - IP address: 10.75.22.18/24 - Default gateway: 10.75.21.1 - Controller: 10.75.22.5 - Other APs joined: yes
Based on the exhibit, which action is most likely required to allow AP-22 to join the controller successfully?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Correct the AP's default gateway so it matches the AP's actual subnet and reachability needs.
This is correct because the current gateway does not align with the AP's subnet, which breaks proper forwarding behavior.
B
Distractor review
Change the AP from Ethernet to PPP encapsulation.
This is wrong because PPP is unrelated to AP controller join behavior on a LAN.
C
Distractor review
Remove the AP IP address so CAPWAP can assign one automatically.
This is wrong because the main clue is the wrong default gateway, not the presence of an IP address itself.
D
Distractor review
Disable DHCP on the controller for all APs.
This is wrong because other APs already join successfully and the symptom points to this AP's local path.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is to confuse AP join failures with encapsulation or DHCP issues. Candidates might incorrectly think that changing the AP’s encapsulation from Ethernet to PPP or disabling DHCP on the controller will fix the problem. However, CAPWAP communication depends on IP routing, not encapsulation type, and DHCP issues would affect all APs, not just one. The trap is to overlook the fundamental Layer 3 reachability problem caused by a mismatched default gateway, which prevents the AP from forwarding join requests to the controller across subnets.
Technical deep dive
How to think about this question
Access points (APs) in a controller-based wireless LAN architecture must communicate with the wireless LAN controller (WLC) using CAPWAP, which operates over UDP/IP. This communication requires the AP to have proper Layer 3 configuration, including an IP address and a default gateway that matches the AP’s subnet. The default gateway is essential for forwarding packets destined for devices outside the AP’s local subnet, such as the controller if it resides on a different subnet. Without correct gateway settings, the AP cannot route CAPWAP join requests to the controller, resulting in join failures. When an AP attempts to join a controller, it sends CAPWAP discovery and join messages. If the AP’s default gateway is misconfigured—pointing to an IP outside the AP’s subnet or unreachable network segment—the AP cannot forward these messages correctly. The controller remains unreachable despite the physical Ethernet link being operational. This scenario is common in troubleshooting AP join issues, where verifying subnet masks and gateway addresses is a critical step. The AP’s IP and gateway must align logically to ensure proper routing. A common exam trap is to focus on unrelated configuration changes, such as encapsulation types or DHCP settings on the controller. For example, changing the AP from Ethernet to PPP encapsulation is irrelevant because CAPWAP uses UDP over IP and Ethernet is the standard LAN encapsulation. Similarly, disabling DHCP on the controller does not help if other APs join successfully, indicating the problem is isolated to the AP’s local network path. Understanding the role of subnetting and gateway configuration prevents these distractions and leads directly to the correct solution.
KKey Concepts to Remember
- An access point (AP) must have correct Layer 3 reachability, including a valid default gateway, to successfully join a wireless LAN controller (WLC).
- The default gateway on an AP directs traffic destined for devices outside the AP's local subnet, enabling communication with the controller if it resides on a different subnet.
- If an AP’s default gateway does not match its subnet, the AP cannot forward CAPWAP join requests properly to the controller, causing join failures.
- CAPWAP (Control And Provisioning of Wireless Access Points) relies on IP routing and subnetting principles to establish control-plane communication between APs and the WLC.
- Ethernet encapsulation is the standard for AP-controller communication on LANs; changing to PPP encapsulation is irrelevant and does not affect AP join behavior.
- Removing a static IP address from an AP does not resolve gateway misconfiguration issues; proper IP addressing and gateway settings are required for Layer 3 connectivity.
- Disabling DHCP on the controller does not impact AP join success if other APs already join successfully, indicating the problem is local to the specific AP’s network configuration.
- Correct subnetting and gateway configuration ensure that APs can reach the controller across Layer 3 boundaries, which is critical for controller-based WLAN deployments.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
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Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
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Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
An access point (AP) must have correct Layer 3 reachability, including a valid default gateway, to successfully join a wireless LAN controller (WLC).
What is the correct answer to this question?
The correct answer is: Correct the AP's default gateway so it matches the AP's actual subnet and reachability needs. — The most likely required action is to correct the AP's Layer 3 reachability toward the controller, starting with its default gateway. In practical terms, the AP has an IP address in one subnet but a gateway in another. That mismatch prevents correct off-subnet communication to the controller even though the Ethernet link is up. Fixing local Layer 3 reachability is the most direct next step. This is a realistic controller-based WLAN support problem because the controller works for other APs, so the fault is likely local to this AP's network path.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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