What roaming event occurs across multiple mobility groups?

350-401 By islever Editorial Last updated

Short answer

C Layer3

Question

Which type of roaming event occurs when a client roams across multiple mobility groups?
  1. Layer1
  2. Layer7
  3. Layer3 Correct Answer
  4. Layer2

Key Takeaways

The exam tests your understanding of intercontroller roaming types; the common trap is assuming Layer 2 roaming applies whenever VLANs aren't explicitly mentioned, but crossing a mobility group boundary always triggers Layer 3 roaming.

When a wireless client roams across mobility group boundaries, a Layer 3 intercontroller roaming event occurs, maintaining the client's IP address via EtherIP tunneling. Community consensus strongly confirms Layer 3 roaming for cross-mobility-group scenarios.

Common mistake: Many candidates choose Layer 2 (Option D) because the question doesn't explicitly mention different VLANs or subnets, overlooking that mobility group boundaries inherently require Layer 3 roaming with EtherIP tunneling.

Expert Analysis

Why the Answer Is Correct

Layer 3 intercontroller roaming occurs specifically when a client roams across mobility group boundaries. During this process, the client maintains its original IP address while an EtherIP tunnel is established between the anchor and foreign controllers to forward traffic. This distinguishes it from Layer 2 intercontroller roaming, which only occurs within the same mobility group when VLAN IDs match between controllers.

Why the Other Options Are Wrong

Layer 1 roaming is not a valid Cisco wireless roaming classification and can be immediately eliminated. Layer 7 refers to application-layer concepts and has no relevance to wireless client roaming events. Layer 2 intercontroller roaming only applies when the client stays within the same mobility group and the VLAN IDs match between the source and destination controllers.

Community Comment Notes

Comment [1] correctly identifies that crossing a mobility group boundary triggers full reauthentication with EtherIP tunneling for Layer 3 roaming. Comment [3] provides an excellent summary: Layer 2 applies to same VLAN and same mobility group, while Layer 3 applies to different VLANs or different mobility groups. Comment [5] represents the common misconception of assuming Layer 2 when VLANs aren't mentioned, but the mobility group boundary is the determining factor.

Exam Strategy

When you see 'mobility group' in a roaming question, immediately think Layer 3 intercontroller roaming. Remember that Layer 2 intercontroller roaming only applies within the same mobility group with matching VLANs, while any mobility group boundary crossing requires Layer 3 roaming with EtherIP tunneling.

Community Votes

C
100%

100% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 7 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 7

  1. ciscoccie20 👍 8
    Should be L3: C When a client crosses a mobility group boundary while a roam, the client is fully authenticated, but the IP address is maintained, and EtherIP tunneling is initiated for Layer 3 roaming.
  2. outnumber_gargle024 👍 5 Answered C
    L3, intercontroller roam between mobility groups
  3. chiacche 👍 3 Answered C
    L2 : Same VLAN, Same mobility group L3 : Different VLAN or mobility group
  4. CCAL 👍 2
    Layer 2 & Layer 3 Intercontroller Roam When a mobile client roams from one AP to another, and if those APs are on different WLCs, then the client makes an intercontroller roam. When a client starts an intercontroller roam, the two WLCs compare the VLAN IDs allocated to their WLAN interfaces. – If the VLAN IDs are the same, the client performs a Layer 2 intercontroller roam. – If the VLAN IDs are different, the WLCs will arrange a Layer 3 or local-to-foreign roam.
  5. c05e44e 👍 1
    There's no mention in the question of different subnets (VLANs), so this is Inter Controller L2 roaming. D
Show 2 more comments
  1. slacker_at_work 👍 2 Answered C
    L3 as per explanation below
  2. c05e44e 👍 1
    see Q #958

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