How to configure Cisco 2960 switches

Troubleshooting tips for Cisco 3750X Stack power feature

Introduction

Cisco Stack Power technology is a new feature introduced in the Cisco catalyst 3750-X series switches that aggregates all of the available power in a stack of swithces and manages it as one common power tool.

The catalyst 3750X has two power supplies per system which allows the power load to be split between them. This system increases tha maximum power per port to 30 Watts to meet the POE+ standard (802.3at). Wih POE+, a 48 port system would need 1440 Watts to provide 30 Watts per port per powered device. Systems with few powered devices might require only one Power Supply in which case second Power Supply can provide one-to-one redundancy for active Power Supply.

A power stack can not contain more than four switches and Power Supplies of these switches can be managed as one large Power Supply that provides power to all switches. In this way, any faulty Power Supply in a single switch can be replaced without taking that switch offline.

Stack Power also allows deployment ofexpandable Power System, XPS 2200 to create large power pools. This system forms a star topology which shares power with upto 9 swicthes and provides improved reliability, availability and efficiency.Requirements

There are no specific requirements.Troubleshooting tips

One of the most common issue seen with Stack Power feature is that even when the switches are in stack, the stack topology is still standalone which means that the power sharing feature has not started yet. The commands used to see this issue and correct it are:

show stack-poweris the command which is used to check whether the feature has started or not. When we don't have any issues, the output would be something like:

Switch#show stack-powerPower stack name: Powerstack1

Stack mode: Power sharing

Switch 1:

Power budget: 206

Low port priority value: 17

High port priority value: 16

Switch priority value: 2

Port A status: Not shut

Port B status: Not shut

Neighbor on port A: 0022.bdcf.ab00

Neighbor on port B: 0022.bdd0.4380

And, in cases when we dont have this feature started yet we will see something like:

Switch#show stack-powerPower stack name: Powerstack-1

Stack mode: Power sharing strict

Stack topology: StandaloneSwitch 3:

Power budget: 1063

Low port priority value: 22

High port priority value: 13

Switch priority value: 4

Port 1 status: ShutPort 2 status: ShutNeighbor on port 1: 0000.0000.0000

Neighbor on port 2: 0000.0000.0000

These ports 1 and 2 are power ports and should be enabled for use of power sharing feature. These ports can be enabled by using following comand in EXEC mode:

switch#stack-power switch 3 port 1 enable

switch#stack-power switch 3 port 2 enable

Please note that these commands are to be issued in EXEC mode. One very common mistake is to type these commands in global configuration mode.

%PLATFORM_STACKPOWER-4-UNDER_BUDGET:This message is observed even when the power supplies looks OK otherwise.This message is also observed in cases when we have just got the power feature started by enabling power ports.

There are few options available to overcome this issue:

1. .Power cycle not reload the switch which is issuing these messages (like switch 2 in above error message)

2. Put the particular switch or all the switches in stack in standalone mode, this can be done by issuing following command:

Switch(config)#stack-power switch 2

Switch(config-switch-stackpower)#standalone

Once this is done, wait for 60-90 seconds and see if the error message goes away. Once the error message ceases, put the switch/switches out of standalone mode by using "no standalone" command.

%PLATFORM_STACKPOWER-4-PRIO_CONFLICT:There is no specific troubleshooting for this issue however, certain guidelines can be followed to avoid such situations:

You can configure priority of a switch and of a powered device. This priority determines which switch/port will shut down first in case of power shortage. You can configure three priorities per system (switch):

1. The system (switch) priority.

2. Priority of high priority POE ports.

3. Priority of low priority POE ports.

On any swicth, the switch priority should be lower than the priority of POE ports and the high priority values must be set lower than the low priority values. It is recommended that you configure different priority values for each switch and its high priority and low priority ports. This limits the number of devices shut down at a time during loss of power. If you try to configure same priority values at different swiitches, the configuration will be allowed but you will receive an error message.

The default priority ranges, if none are configured, are 1-9 for switches, 10-18 for high-priority ports, and 19-27 for low-priority ports.

Troubleshooting examples

Problem Description:After configuring stack mode redundant, power redundancy through stack-wise not working

Symptoms:

An Error Message:

%PLATFORM_STACKPOWER-4-REDUNDANCY_LOSS: Switch 2's power stack lost redundancy and is now operating in power sharingmodeSwitch3750-X#show stack-powerPower stack name: Powerstack1

Stack mode: Redundant

Stack topology: Standalone

Switch 2:

Power budget: 1663

Low port priority value: 22

High port priority value: 13

Switch priority value: 4

Port 1 status: ShutPort 2 status: Connected

Neighbor on port 1: 0000.0000.0000

Neighbor on port 2: f866.f25a.7d00

Output of the command show stack power shows the port status as Shut

Output of the command "show environment power"

Switch3750-X#sho env powerSW PID Serial# Status Sys Pwr PoE PwrWatts

----- ------- -------------- --------------- --------------- ------ --------------

1A C3KX-PWR-715WAC AAAAAAAA0F4 OK Good Good 715/0

1B Not Present

Troubleshooting Steps:

1. Redundancy is configured however the power stack ports are shut

2. Enable all power stack ports by command stack-power switch [number] port [number] enable

Switch3750-X#stack-power switch 2 port 1 enable

It is referred from https://supportforums.cisco.com/document/72421/troubleshooting-tips-3750x-stack-power-featureMore related:Cisco 3750-X Series Switches OverviewCisco Catalyst 3750-X and 3560-X Express SetupCisco Catalyst 3750-X VS 3560-X Series SwitchesCisco Catalyst 3750-X and 3560-X Network ModulesCisco 3850 Series Switches Vs Cisco 3750-X SwitchesThe Benefits of Cisco Catalyst 3750-X and 3560-X IP Services SwitchMore Cisco products and Reviews you can visit: http://www.3anetwork.com/blog 3Anetwork.com is a world leading Cisco networking products supplier, we wholesale original new Cisco networking equipments, including Cisco Catalyst switches, Cisco routers, Cisco firewalls, Cisco wireless products, Cisco modules and interface cards products at competitive price and ship to worldwide.Our website: http://www.3anetwork.comTelephone:+852-3069-7733

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