A network administrator needs to improve network monitoring. Which of the following should the administrator do first?

Establishing baseline metrics involves collecting data on normal network performance, such as traffic, latency, and resource utilization, over a period. This creates a reference point for identifying deviations and anomalies, which is essential before any other monitoring activities can be effectively interpreted as either normal or problematic.

Implementing a SIEM is an advanced monitoring solution but requires baselines to effectively correlate events and detect actual security incidents rather than normal operational fluctuations.

Performing regular packet captures is a diagnostic tool for detailed analysis of specific traffic when issues arise, not a primary first step for overall network monitoring improvement.

Conducting availability monitoring is a specific aspect of monitoring but cannot be effectively interpreted without understanding what constitutes a 'normal' or 'expected' level of availability, which baselines provide.