Network Sensor

Temp - most devices report on their own sensor.

Temperature sensors can e used to measure intake and outake

minor threshold - a rise in temp is detected.

major threshold - the temp reaches a dangerous conditipon. device can start to load shed.

cpu usage - under normal conditions cpu should hae minimal utilization in the range of 5%-40%

high CPU can cause a router or deive to start to drop packets.

misconfigured network

network under attack.

Memory utilization baseline 40% , busy 60% to 70% peak up to 80%

minor threshold

severe threshold

critical threshold

📊 Network Sensors & Monitoring

🌡️ Temperature Sensors

• Most devices (switches, routers, servers) have built-in sensors.
• Measure intake vs. exhaust air.

Thresholds:

• Minor: Temp rises above baseline.
• Major: Dangerous condition; device may load shed (reduce performance).
• Critical: Device may shut down to protect hardware.

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⚙️ CPU Utilization

• Normal baseline: ~5%–40%.
• High CPU → device may drop packets or fail to forward traffic.
• Causes:
  • Misconfiguration.
  • Network under attack (DDoS, excessive traffic).

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🧠 Memory Utilization

• Baseline: ~40%.
• Busy: 60%–70%.
• Peak: up to 80%.

Thresholds:

• Minor: approaching 60%.
• Severe: 70%+.
• Critical: 80%+ (risk of crashes or packet drops).

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✅ Exam Tips

• Sensors provide early warning signs for overheating, high CPU, or memory exhaustion.
• Know difference between minor, major/severe, and critical thresholds.
• High CPU/memory can be caused by attacks, misconfigurations, or failing hardware.

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⚡ Sample Exam Question:

“A router begins dropping packets during normal traffic loads. Monitoring shows CPU utilization at 90%. What’s the most likely cause?”

→ Device is overloaded due to high CPU utilization.

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👉 Build a baseline-and-threshold quick chart (Temp, CPU, Memory) so normal, warning, and critical values stay top of mind.