How to Anchor AireOS Guests Behind a Catalyst 9800 Foreign Controller?
A new wireless network design has these requirements: • AireOS WLCs as guest anchors • a Cisco Catalyst 9800 Series WLC as the foreign controller • use of Wi-Fi 6 APs • inter-controller roaming for guest users Which two design approaches meet these requirements? (Choose two.)
Community Votes
71% of anonymous learners picked answer BE. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The question tests inter-release mobility between AireOS and 9800 controllers; the trap is assuming EoIP still carries guest traffic in a mixed-controller design.
Mixing AireOS guest anchors with a Cisco Catalyst 9800 foreign controller for Wi-Fi 6 guest roaming requires WLC software that supports IRCM plus a secure mobility tunnel between the controllers. This page confirms answers B and E and explains why EoIP, AVC, and IPv6 do not satisfy the design.
Choosing A (EoIP) because it is the familiar AireOS mobility transport — EoIP only works AireOS-to-AireOS, so it cannot link a 9800 foreign controller to AireOS anchors.
Community Discussion (4 comments)
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Expert Analysis
Why the Answer Is Correct
When guest anchors run AireOS and the foreign controller is a Catalyst 9800, the two platforms must interoperate across software generations, which is exactly what Inter-Release Controller Mobility (IRCM) provides — so the AireOS WLCs must run an IRCM-capable software version (B). Because the tunnel endpoints are different controller families, mobility is established as a Secure Mobility Tunnel with control messages on port 16666 and data on 16667, so the controllers must be paired using secure mobility (E). Together, IRCM software plus a secure mobility pairing delivers the inter-controller roaming the guest design requires. The Wi-Fi 6 AP requirement simply reinforces the 9800 side of the design, since those APs terminate on the foreign controller while client traffic is anchored to the AireOS guest anchors. The community vote (BE, 71 votes) agrees with this platform-level reading.Why the Other Options Are Wrong
EoIP (A) is the legacy AireOS mobility transport; as Jonycici noted, "EoIP will be used only between two AireOS" controllers, so it cannot connect AireOS anchors to a Catalyst 9800 foreign controller. AVC (C) is an application-visibility feature for classifying and prioritizing traffic on the anchor — it has nothing to do with establishing mobility or anchoring tunnels. IPv6 (D) is a transport/address-family choice and is not a mobility design requirement for guest anchoring between AireOS and 9800. Even ShamsDimashki, who proposed A+B, framed it as an open question, and the platform documentation path favors B+E.Community Comment Notes
Jonycici provided the decisive technical detail, describing the secure link as a "Secure Mobility Tunnel" using control tunnel 16666 and data tunnel 16667, and stating plainly that "EoIP will be used only between two AireOS" — which rules out option A. That same commenter answered BE, matching the majority of 71 voters versus 29 for AB. ShamsDimashki floated A+B and asked for comments, an understandable pull toward the older AireOS transport, but the mixed 9800/AireOS topology is precisely the case where secure mobility replaces EoIP. Rododendron2's terse "BE, BE" reflects the community consensus without adding new reasoning.Official Reference
Exam Strategy
Memorize the pairing rule: AireOS-to-AireOS mobility uses EoIP, while any design that mixes Catalyst 9800 with AireOS requires an IRCM-capable image and secure mobility tunnels on ports 16666/16667.
Frequently Asked Questions
Why is EoIP wrong when the guest anchors are AireOS controllers?
EoIP is only supported between two AireOS controllers, so it cannot tunnel mobility or anchored guest traffic between an AireOS anchor and a Catalyst 9800 foreign controller.
What does IRCM change in this mixed 9800 and AireOS design?
IRCM lets controllers running different software releases interoperate, which is required so the 9800 foreign controller can roam guests to AireOS anchors over secure mobility tunnels.