300-365 · Question #37
A customer has implemented a N+1 high availability plan in a multistory building. All APs on odd numbered floors are set as primary to WLC-A and all APs on even numbered floors are set as primary to…
The correct answer is A. inconsistent CleanAir data due to multiple WLCs C. AVC inconsistency due to multiple mobility group members. Splitting APs across two WLCs by floor in an N+1 design fragments features that aggregate data at the WLC level, specifically CleanAir spectrum analysis and AVC policy enforcement.
Question
A customer has implemented a N+1 high availability plan in a multistory building. All APs on odd numbered floors are set as primary to WLC-A and all APs on even numbered floors are set as primary to WLC-8. Which two problems are likely to arise from this design? (Choose two)
Options
- Ainconsistent CleanAir data due to multiple WLCs
- Bfloor-to-floor bleed-through that causes intercontroller roaming delays
- CAVC inconsistency due to multiple mobility group members
- Dlegacy device compatibility with multiple WLC configuration that causes disconnects
- Eunpredictable AP loading during a WLC failure
How the community answered
(37 responses)- A59% (22)
- B11% (4)
- D8% (3)
- E22% (8)
Why each option
Splitting APs across two WLCs by floor in an N+1 design fragments features that aggregate data at the WLC level, specifically CleanAir spectrum analysis and AVC policy enforcement.
CleanAir aggregates RF interference data at the WLC level, so APs on adjacent floors reporting to separate WLCs produce fragmented spectrum views, preventing a unified and consistent interference picture across the building.
Floor-to-floor RF bleed-through is a physical propagation characteristic determined by building construction, not by how APs are distributed across WLC assignments.
AVC policies are configured and enforced per-WLC, so when clients roam between APs anchored to different WLCs with potentially differing AVC profiles, application classification and QoS enforcement becomes inconsistent across the mobility domain.
Legacy device compatibility is governed by 802.11 protocol support and WLAN security settings configured on each WLC independently, not by the N+1 primary/secondary WLC topology.
In an N+1 design, failover behavior is predictable - all APs primary to the failed WLC will join the surviving WLC according to configured secondary assignments, so the loading result is expected and not unpredictable.
Concept tested: N+1 HA design impact on CleanAir and AVC
Source: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-8/b_High_Availability_deployment_guide.html
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