PASSEDnetwork / poe_budget_exhaustion

PoE Budget Exhaustion on Switch

A 48-port PoE+ switch reaches its PoE power budget after 12 new WiFi 6E APs are connected, causing the switch to cut power to lower-priority devices including phones and security cameras.

Pattern

UNKNOWN

Severity

CRITICAL

Confidence

95%

Remediation

Remote Hands

Test Results

Metric	Expected	Actual
Pattern Recognition	UNKNOWN	UNKNOWN
Severity Assessment	CRITICAL	CRITICAL
Incident Correlation	Yes	22 linked
Cascade Escalation	N/A	No
Remediation	—	Remote Hands — Corax contacts on-site support via call, email, or API

Scenario Conditions

Catalyst 9300-48P with 740W PoE budget. 36 existing PoE devices (phones, cameras, APs). 12 new WiFi 6E APs added (30W each = 360W additional). Total demand: 810W exceeds 740W budget. Switch shedding power from low-priority ports.

Injected Error Messages (2)

PoE budget exhaustion on Cat9300-48P — total PoE demand: 810W exceeds available budget: 740W, switch power-shedding low-priority ports (class 2 and class 3), 8 phones and 4 security cameras powered off by PoE priority enforcement, PoE allocation: 12 WiFi 6E APs consuming 360W (class 4/6), remaining budget insufficient for all connected devices, PoE overload alarm triggered

IP phones losing PoE power on floor 3 — 8 phones shut down after switch PoE budget exceeded, phones on lower-priority ports (configured as class 2) powered off by PoE inline power management, users on floor 3 unable to make calls from desk phones, PoE power allocation policy favoring high-power APs over phones, phone service disruption for 8 users until PoE budget rebalanced

Neural Engine Root Cause Analysis

The Cat9300-48P access switch is experiencing PoE budget exhaustion where total power demand (810W) exceeds the switch's available PoE budget (740W). This has triggered automatic power-shedding of lower priority devices, causing 8 phones and 4 security cameras to lose power while 12 high-priority WiFi 6E APs continue operating. The 12 correlated incidents likely represent the downstream devices that have been powered off due to PoE priority enforcement.

Remediation Plan

1. Immediately identify non-critical PoE devices that can be temporarily disconnected to free up power budget. 2. Review and adjust PoE priority settings to ensure critical devices (phones, security cameras) have higher priority than some WiFi APs if business requirements allow. 3. Calculate exact power requirements and consider: a) Installing additional PoE injectors for some devices, b) Upgrading to a higher capacity PoE switch, or c) Adding a secondary switch to distribute the load. 4. Monitor power consumption patterns to prevent future exhaustion. 5. Implement PoE monitoring alerts before reaching 90% capacity.

Tested: 2026-03-30Monitors: 2 | Incidents: 2Test ID: cmnckazop083zobqe2jgmj25b