Network Monitoring: The Five Numbers

Network monitoring is often network-team-only. SREs benefit from these five numbers being visible.

Why five

Network issues hide in app metrics; surface only when the wire is observable.

Five metrics catch most.

The five metrics

• 1. Packet loss rate.
• 2. Latency p99 to dependencies.
• 3. Connection-error rate.
• 4. DNS resolution time p99.
• 5. TLS handshake time p99.

Dashboard pattern

One panel per metric; trend over 24h.

Per-dependency drill-down for 2-5.

Alert thresholds

Packet loss: alert above 0.1% sustained.

Latency: alert on 50% increase from baseline.

Errors: alert on 2x baseline.

DNS: alert above 100ms p99.

TLS: alert above 200ms p99.

Antipatterns

• App-only monitoring. Misses network root causes.
• One global metric. Hides per-dependency issue.
• Threshold without baseline. Wrong alarm rate.

What to do this week

Three moves. (1) Apply this pattern to your highest-risk network path. (2) Measure the failure mode rate before/after. (3) Document the change so the next incident-responder inherits the knowledge.