When performing an In-Service Software Upgrade (ISSU) on a Cisco Nexus 9500 Series switch, certain features may cause a disruptive upgrade due to their control plane dependencies. VXLAN (Virtual Extensible LAN) requires protocol enhancements that impact forwarding operations, making it not ISSU-compatible. As a result, VXLAN deployments will experience a disruptive upgrade when performing a standard ISSU.