Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
Controller status: - 14 APs joined successfully AP-15 status: - Power on: yes - Ethernet link: up - IP address: 10.60.15.44/24 - Default gateway configured: 10.60.14.1 - Controller management IP: 10.60.15.10
Based on the exhibit, what is the strongest explanation for why one AP never joins the wireless controller while the others do?
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
The AP has an incorrect default gateway for its subnet.
This is correct because 10.60.15.44/24 should not use 10.60.14.1 as its local default gateway.
B
Distractor review
CAPWAP can be used only if the AP has no IP address.
This is wrong because the AP does need valid IP connectivity to join the controller.
C
Distractor review
The AP must use PPP instead of Ethernet to reach the controller.
This is wrong because controller-based APs do not require PPP to join over Ethernet networks.
D
Distractor review
The controller can support only 14 APs maximum.
This is wrong because the exhibit does not indicate any capacity limit and the symptoms point to a local path issue.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to believe that an AP cannot use CAPWAP if it has an IP address or that the controller’s AP capacity is the cause of join failures. Candidates might also incorrectly assume the AP must use a special protocol like PPP instead of Ethernet. These misconceptions distract from the real issue: the AP’s incorrect default gateway prevents proper routing of CAPWAP packets. This trap leads to wasted troubleshooting effort on controller limits or protocol misunderstandings instead of verifying the AP’s IP routing configuration.
Technical deep dive
How to think about this question
In Cisco wireless networks, Access Points (APs) join a wireless LAN controller (WLC) using the Control and Provisioning of Wireless Access Points (CAPWAP) protocol. This process requires the AP to have proper Layer 3 connectivity to the controller, including a valid IP address, subnet mask, and default gateway. The default gateway is critical because it enables the AP to route CAPWAP control traffic beyond its local subnet to reach the controller. Without a correct default gateway, the AP cannot forward packets destined for the controller if it resides on a different subnet. When an AP fails to join the controller while others succeed, the troubleshooting focus shifts to the AP's network configuration and path to the controller. The AP’s IP address and subnet mask must align with the network design, and the default gateway must be the correct router interface for that subnet. If the AP uses an incorrect default gateway, it cannot route CAPWAP packets properly, causing join failures. This is a common issue in multi-subnet wireless deployments where APs are distributed across different VLANs or IP segments. A common exam trap is to assume that CAPWAP requires the AP to have no IP address or that the controller limits the number of APs it supports. These misconceptions overlook the fundamental requirement of IP routing for CAPWAP traffic. In practice, the AP must have a valid IP configuration, including a correct default gateway, to reach the controller. Misconfigurations in the AP’s default gateway often cause join failures, while controller capacity limits or protocol misunderstandings rarely cause isolated AP join issues when others are successful.
KKey Concepts to Remember
- An Access Point must have a valid IP address and subnet mask to communicate with the wireless LAN controller over CAPWAP.
- The default gateway on an AP determines how it routes traffic destined for devices outside its local subnet, including the wireless controller.
- If an AP has an incorrect default gateway, it cannot forward CAPWAP control packets to the controller, causing join failures.
- CAPWAP requires Layer 3 connectivity; the AP cannot join the controller without proper IP routing to the controller's subnet.
- Wireless LAN controllers do not limit AP joins based on a fixed maximum number in typical exam scenarios; join failures usually indicate network path issues.
- An AP must have an IP address to use CAPWAP; the protocol does not operate without IP connectivity.
- Troubleshooting isolated AP join failures focuses on verifying the AP’s IP configuration and routing path rather than controller capacity or protocol misuse.
- Correct subnetting and gateway configuration are essential for APs distributed across multiple VLANs or IP subnets to successfully join the controller.
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
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
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
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
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 must have a valid IP address and subnet mask to communicate with the wireless LAN controller over CAPWAP.
What is the correct answer to this question?
The correct answer is: The AP has an incorrect default gateway for its subnet. — The strongest explanation is that the failing AP cannot reach the controller through the correct control path, even though other APs can. In practical terms, this points to a problem specific to that AP's network path, addressing, or controller reachability rather than a global WLAN outage. Because other APs already join successfully, the controller itself is probably working. This is a realistic controller-based WLAN troubleshooting pattern because it focuses on isolating whether the problem is global or per-device.
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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