Refer to the exhibit.

The Virtual Switching Link (VSL) is essential for communication between the active and standby Wireless LAN Controllers (WLCs) in a Stateful Switch Over (SSO) setup. If the VSL goes down, it can lead to a split-brain scenario where both WLCs assume they are active, causing network disruptions and inconsistencies in client handling. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425) Official Cert Guide.