Introduction
This document describes how to calculate the actual power consumption on a Catalyst 9300 switch stack.
Prerequisites
Requirements
Cisco recommends that you have knowledge of these topics:
- Understanding of Cisco Catalyst 9300 series switch hardware architecture and stacking capabilities
- Cisco IOS XE command-line interface (CLI)
- Knowledge of power management concepts for LAN switching, including Power over Ethernet(PoE) budgeting
Components Used
The information in this document is based on these software and hardware versions:
- Cisco Catalyst 9300 Series.
- Stacked switch topology.
- Software Version: Cisco IOS XE 17.12.4.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.
Background Information
Cisco Catalyst 9300 switches support stacking, allowing multiple physical switches to operate as a single logical unit. Effective power management in stack environments is critical, particularly when using features like Power over Ethernet (PoE) to supply power to connected devices such as IP phones, wireless access points, and cameras. Power consumption monitoring enables network engineers to ensure that the stack operates within safe and efficient power budgets. It also helps in planning for redundancy and additional PoE endpoints. The Catalyst 9300 provides built-in CLI commands to display detailed power usage and allocation per stack and per switch member.
Problem
The objective is to identify the total power consumption by a Cisco Catalyst 9300 switch stack. Network engineers are required to obtain accurate, real-time data on how much power (in watts or milliwatts) is being used by the system as a whole, as well as by individual stack members, including both system and PoE loads.
Solution
Method 1: Access the Stack Power Budgeting Information
Use this command to display detailed power data for the stack, including total power, reserved power, allocated power, and available power for each stack and member.
Device#show stack-power budgeting
Power Stack Stack Stack Total Rsvd Alloc Sw_Avail Num Num
Name Mode Topolgy Pwr(W) Pwr(W) Pwr(W) Pwr(W) SW PS
-------------------- ------ ------- ------ ------ ------ ------ ----- -----
Powerstack-1 SP-PS Ring 2145 30 729 1386 3 3
Powerstack-2 SP-PS Stndaln 715 0 333 382 1 1
Power Stack PS-A PS-B Power Alloc Poe_Avail Consumd Pwr
SW Name (W) (W) Budgt(W) Power(W) Pwr(W) Sys/PoE(W)
-- -------------------- ----- ----- -------- -------- -------- ------------
1 Powerstack-1 0 715 693 243.0 450.0 74.1/0.0
2 Powerstack-2 0 715 715 333.0 382.0 74.4/33.6
3 Powerstack-1 0 715 712 243.0 469.0 68.9/0.0
4 Powerstack-1 0 715 710 243.0 467.0 68.9/0.0
-- -------------------- ----- ----- -------- -------- -------- ------------
Totals: 1062.0 1768.0 286.4/33.6 <<< The sum of these 2 values is the total power consumed
This output shows the total system power consumption: The total power used by the system (286.4W) and PoE devices (33.6W).
Summing these values provides the actual power consumption of all switches in the stack plus the PoE devices.
In this case, 320 W.
Method 2: Access Environmental Power Output Details
Run this command to view the output power for each Power Supply Unit(PSU) in the stack.
Device#show environment all | include POWout
PS2 POWout 1 GOOD 84000 mW na
PS2 POWout 2 GOOD 108000 mW na
PS2 POWout 3 GOOD 62000 mW na
PS2 POWout 4 GOOD 66000 mW na
This output lists the direct current power output (in milliwatts) for each detected power supply. Summing these values provides the actual power consumption across all power supplies in the stack.
In this case, 320000 mW or 320 W.
Note: The values shown in this article are measured after the current is converted from alternating to direct. So all the values show direct current power consumption. If you are measuring the power consumption before the conversion, the value is different.
Note: These 2 methods use real time data to get power consumption. If you want to use both, you can get different output depending on if you run the commands at different times.
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