What are the required configurations for a WLC mobility group?
Short answer
CE Each WLC must use the same mobility domain name, and the WLAN SSID must be consistent across all the WLCs for roaming.
Question
Key Takeaways
The question tests the fundamental requirements for inter-controller mobility, trapping learners who confuse SSO HA virtual IP requirements with the mobility group's global virtual IP requirement.
This page clarifies the mandatory design configurations for a Cisco WLC mobility group, specifically addressing SSID consistency and mobility domain names. It explains why all WLCs must share the same mobility domain name and WLAN SSID for seamless inter-controller roaming.
Common mistake: Option B> B is commonly chosen because learners mistakenly believe only SSO HA pairs require the same virtual IP/anchor IP, ignoring that all WLCs in a mobility group must share the same virtual interface IP.
Expert Analysis
Why the Answer Is Correct
For a WLC mobility group to function correctly and allow clients to seamlessly roam, each WLC must be configured with the same mobility domain name. Additionally, the WLAN SSID and security parameters must be consistent across all WLCs in the mobility group; otherwise, client devices will not recognize the roaming candidate as the same network.
Why the Other Options Are Wrong
Option A is incorrect because mobility groups can consist of different WLC models as long as they run compatible AireOS versions. Option B is incorrect because all WLCs in a mobility group, not just the SSO pair, must use the same virtual interface IP address to ensure proper mobility communication. Option D is incorrect because WLCs in a mobility group only need to run compatible software versions (e.g., 8.0 or later), not the exact same version.
Community Comment Notes
Several community members initially debated option B, but as one user noted, "all WLCs in the mobility group have to have same Virtual IP," which invalidates option B. Another user correctly pointed out that "Controllers do not have to be of the same model to be a member of a mobility group," ruling out option A. Furthermore, the consensus confirms that "D is wrong" because exact version matching is not required across the entire mobility group.
Official Reference
https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-7/High_Availability_DG.html
This link opens the official vendor documentation in a new tab.
Exam Strategy
When evaluating mobility group requirements, always distinguish between HA SSO pair prerequisites (same model, same exact version) and general mobility group prerequisites (same virtual IP, same mobility domain, same SSID). Remember that the exact software version is only mandatory for SSO pairing, not the entire mobility group.
Community Votes
75% of anonymous learners picked answer CE. 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
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Bandito 👍 3CE, I agree with learningccnp. First I thought it shall be BE, but reading documentation I found that all WLCs in the mobility group have to have same Virtual IP.
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learningccnp 👍 3D is wrong. Does not really need it.
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SrStew 👍 2Answer is b and e SSO uses a virtual ip much like hsrp. They are the only ones needing it in the design. SSID doesn't need to be consistent across controllers for this question
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raptuz 👍 1I created a lab where I simulated the 4 WLCs. SSO settings are not available in vWLCs so reading the article: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-7/High_Availability_DG.html The Virtual IP Address is a requirement for HA: HA Pairing is possible only between the same type of hardware and software versions. Mismatch may result in Maintenance Mode. The Virtual IP Address should be the same on both the WLCs before configuring SSO. So B is correct. At that point I created different SSIDs on all the WLCs and used different software versions 8.5 and 8.10, so I excluded C and D. A is not correct because it is possible to create Mobility Groups between 3504, 5508, 5510, etc..... The only correct ones are B and E
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Farhad123 👍 1In an SSO (Stateful Switchover) pair, the active and standby WLCs share a single virtual IP address. This ensures seamless failover without impacting client sessions. Other WLCs in the Mobility Group (but not in HA mode) must use different virtual IPs.
Show 2 more comments
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Farhad123 👍 1Controllers do not have to be of the same model to be a member of a mobility group. Mobility groups can be comprised of any combination of controller platforms as long as the controllers are running compatible AireOS versions
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SrStew 👍 1https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-7/High_Availability_DG.html
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