What Tunnel Type Enables Intercontroller Roaming Between WLCs?

350-401 By islever Editorial Last updated

Short answer

C mobility

Question

Which type of tunnel is required between two WLCs to enable intercontroller roaming?
  1. CAPWAP
  2. LWAPP
  3. mobility Correct Answer
  4. IPsec

Key Takeaways

This question tests precise architectural terminology versus underlying protocols, requiring candidates to identify the functional tunnel type rather than the encapsulation method.

Intercontroller roaming requires a mobility tunnel between wireless LAN controllers to securely exchange client session data. Although CAPWAP often serves as the underlying transport, Cisco officially classifies this connection as a mobility tunnel.

Common mistake: Candidates frequently select CAPWAP because it is the dominant protocol for AP-to-WLC communication and frequently forms the carrier for controller links, causing them to overlook the question's specific request for the tunnel's designated type.

Expert Analysis

Core Concept

The correct answer is C. mobility. In Cisco wireless architecture, a mobility tunnel is the dedicated logical connection established between two Wireless LAN Controllers (WLCs) within the same mobility domain. Its primary function is to securely exchange client context, authentication state, and forwarding information when a wireless client roams from an access point managed by one controller to another.

Why CAPWAP is Incorrect

While many candidates choose A. CAPWAP, this represents a common terminology trap. CAPWAP (Control And Provisioning of Wireless Access Points) is the underlying protocol used primarily for communication between lightweight APs and WLCs. In Layer 3 intercontroller roaming scenarios, the mobility tunnel may indeed be encapsulated within a CAPWAP datagram, but the tunnel itself is architecturally defined and configured as a mobility tunnel. The question explicitly asks for the tunnel 'type,' making 'mobility' the precise and expected answer.

Other Options

B. LWAPP is a deprecated predecessor to CAPWAP and is not used in modern deployments. D. IPsec provides encryption and integrity but is not the standard mechanism for managing roaming handoffs or sharing client session state between controllers.

Expert Tip

As noted in community discussions, always align your answer strictly with Cisco's official nomenclature. Configuration guides consistently refer to these connections as 'mobility tunnels,' regardless of whether they run over CAPWAP or other transports. Memorizing the functional role of each tunnel type will prevent confusion between protocol and architecture.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When certification questions ask for a specific architectural component or tunnel type, prioritize the official functional name over the underlying transport protocol. Even if a protocol like CAPWAP technically carries the traffic, the exam expects the exact terminology used in Cisco design guides. Always verify terminology against official configuration documentation before selecting an answer.

Community Votes

C
71%
A
29%

71% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 22 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 22

  1. Shri_Fcb10 👍 7 Answered C
    mobility tunnel allows the controllers to share information about client devices, facilitating seamless roaming as clients move between access points managed by different controllers. CAPWAP is used primarily for communication between WLCs and their associated access points. It manages the configuration, control, and management of APs. While CAPWAP tunnels do carry data and control traffic between APs and WLCs, they are not specifically used to facilitate intercontroller roaming.
  2. apetrov 👍 3 Answered A
    A Layer 3 intercontroller roam involves building an additional CAPWAP tunnel between the client’s initial WLC and the WLC to which it has roamed. The tunnel transmits the data to and from the client just like it is still associated with the original IP subnet and WLC. When a Layer 3 roam happens, the original WLC is called the anchor controller, and the current WLC where the roamed client is reassociated is called the foreign controller. The client is anchored to the original WLC even if it roams to different controllers.
  3. jaurelius1420 👍 3 Answered C
    It is asking for, "TYPE" of tunnel. Not the protocol used. C is the most specific answer to this question - always go exactly what is being asked. https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213913-building-mobility-tunnels-on-catalyst-98.html
  4. stefanxradu 👍 2 Answered A
    "Recall that Cisco controllers use CAPWAP tunnels to connect with lightweight APs. CAP- WAP tunnels are also built between controllers for Layer 3 roaming. The tunnel tethers the client to its original anchor controller (and original IP subnet), regardless of its location or how many controllers it roams through." - OCG On page 551 of the OCG you can also see a clear picture of the tunnel between the 2 WLCs
  5. TKSuperstar 👍 2
    To enable inter-controller roaming (or inter-controller mobility) between two WLAN Controllers (WLCs), a Layer 3 tunnel is typically required. This type of tunnel allows client session information to be securely transferred between the controllers, facilitating seamless handoff of clients as they move between different areas covered by different controllers within the same mobility domain. Ans: A
Show 17 more comments
  1. roger_stitching 👍 2
    from OCG Chapter 19 page 550: Recall that Cisco controllers use CAPWAP tunnels to connect with lightweight APs. CAPWAP tunnels are also built between controllers for layer 3 roaming. The tunnel tethers the client to its original anchor controller (and original IP subnet), regardless of its location or how many controllers it roams through. answer is A
  2. AbdullahMohammad251 👍 2 Answered C
    CAPWAP tunnels are used between AP(s) and WLC(s) Mobility tunnels are used between WLCs to enable Intercontroller Layer 3 Roaming Check figure 3: https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-10/config-guide/b_cg810/overview.html#:~:text=Figure%203.-,Intercontroller%20Layer%203%20Roaming,-Layer%203%20roaming
  3. ExamTaker1017 👍 2 Answered C
    The answer is C. Regardless if the WLCs use CAPWAP (used by 9800s) or EoIP (used by AireOS), the tunnels they create are still referred to as "mobility" tunnels. https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-8/b_c9800_wireless_controller-aireos_ircm_dg.pdf
  4. ROBZY90 👍 2 Answered A
    The Cisco Catalyst 9800 Series Wireless Controller mobility tunnel is a CAPWAP tunnel with control path (UDP 16666) and data path (UDP 16667). The control path is DTLS encypted by default. Data path DTLS can be enabled when you add the mobility peer.
  5. HammyHamster 👍 2
    Answer appears to be C. While it's true that mobility tunnels are build from CAPWAP tunnels both GPT4 and the following link are saying mobility https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/overview.html
  6. outnumber_gargle024 👍 2 Answered C
    Should be C. Mobility WLCs need mobility tunnels in order for clients to roam between APs on the different controllers. I promise lol
  7. JeremieB 👍 2 Answered C
    Mobility for intercontroller roaming. https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/overview.pdf
  8. raw007 👍 2
    For Layer 3 intercontroller roaming its CAPWAP. But its not true for Layer 2 inter controller roaming.
  9. night_wolf_in 👍 2 Answered C
    ill pick C, cause it asks for "type", not for protocol
  10. zbeugene7 👍 1
    The key is "inter-controller". Each type is used for a different use case: "mobility" tunnel is used for inter-subnet roaming CAPWAP tunnel for inter-controller roaming. https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/mobility.html
  11. felix_simon 👍 1
    A Intercontroller Roaming, which occurs when the wireless LAN interfaces of controllers are on the same IP subnet. CAPWAP tunnel Intersubnet Roaming, which occurs when the wireless LAN interfaces of controllers are on different IP subnets. Mobility tunnel
  12. zbeugene7 👍 1
    Intersubnet - Mobility Intercontroller -CAPWAP https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/mobility.html
  13. masrur 👍 1 Answered A
    A Layer 3 intercontroller roam involves building an additional CAPWAP tunnel between the client’s initial WLC and the WLC to which it has roamed.
  14. chiacche 👍 1 Answered A
    To enable intercontroller roaming, a CAPWAP channel needs to be established between two WLCs.
  15. issa1430 👍 1
    Between to WC is CAPWAP according to the Cisco docs
  16. Wanessamgp 👍 1 Answered A
    I'm voting A because of question 935.
  17. Adalberto 👍 3 Answered C
    C is correct

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