One user has reported connectivity issues; no other users have reported problems.

In a FortiSASE deployment, Digital Experience Monitoring (DEM) is the primary diagnostic tool used to troubleshoot connectivity and performance issues specifically for a single user or endpoint.

End-to-End Visibility: DEM provides real-time, end-to-end visibility into the network path between the end-user's device and the application they are trying to reach. This is critical when only one user reports an issue, as it allows administrators to pinpoint whether the problem resides on the local device, the local ISP, the SASE backbone, or the destination application.

Performance Metrics: The DEM agent (often integrated with the FortiMonitor agent on the endpoint) collects granular performance metrics such as latency, jitter, packet loss, and RTT (Round Trip Time). It also provides device-specific health data, including CPU and memory usage, to determine if the connectivity issue is actually caused by the remote computer's performance.

Hop-by-Hop Analysis: Unlike standard monitoring, DEM offers End-to-End Continuous Hop Analytics. This path monitoring visualizes every "hop" in the traffic route and highlights exactly where degraded service is occurring. For a single user experiencing issues while everyone else is fine, this tool immediately triangulates if a specific "problem hop" in their unique connection path is the cause.

Operational Comparison: * MDM (A) is used for managing device configurations and software distribution, not for real-time network performance troubleshooting.

Forensics (C) is a security-focused service used for investigating malware incidents or data breaches, not for measuring network latency.

SOCaaS (D) is a managed security service for threat monitoring and event triage; while it handles "security" connectivity issues (like a blocked IP), it is not a tool for performance metric evaluation.