How Do I Know If My Cisco Switch Is Stacked?

To determine if your Cisco switch is part of a stack, the most reliable method is to use specific commands in the switch's command-line interface (CLI). Additionally, physical inspection can provide visual clues.

CLI Commands to Verify Stack Status

Cisco switches, depending on their model series (e.g., Catalyst, CBS), offer different commands to display stacking information.

1. `show stack` Command (for CBS 250/350 Series and similar)

For Cisco Business (CBS) series switches like the CBS250 and CBS350, you can directly query the stack operational status.

Command: show stack
What to look for: This command will display details about the stack members, their roles (e.g., Master, Backup, Member), and their operational status. If the command executes and shows multiple units with roles, your switch is part of a stack. If it indicates no stack is formed or only shows a single unit, it's not stacked.

Example Output (conceptual for show stack):

Switch/Stack Mac Address : xx:xx:xx:xx:xx:xx
                                 Stack Mode         : Active
                                 Stack Protocol     : v1
                                 Stack Toplogy      : Ring
                                 Stack Port Speeds  : 10G
                                 Stack Member Count : 2

                                 Stack ID    Role      MAC Address        Pri   State     
                                 -------     ----      -----------------  ---   --------- 
                                 1           Master    xx:xx:xx:xx:xx:xx  1     Ready     
                                 2           Member    yy:yy:yy:yy:yy:yy  1     Ready

2. `show switch` Command (for Catalyst Series)

For many Cisco Catalyst series switches (e.g., 2960-X, 3750, 3850, 9300), the show switch command is the primary method to check stacking status.

Command: show switch
What to look for:
- Multiple Entries: If you see more than one switch listed with different numbers (e.g., Switch 1, Switch 2), it indicates a stack.
- Roles: Each entry will typically show a role like "Master," "Standby," or "Member" (or "Active," "Standby," "Member").
- Priority: You'll see the stack priority assigned to each member.
- State: The operational state (e.g., "Ready").

Example Output for show switch on a Catalyst stack:

Switch/Stack Mac Address : 0000.0000.0001 - Local Mac Address
                                  Mac persistency wait time: Indefinite
                                                                       H/W   Current
Switch#  Role      Mac Address     Priority Version  State
------------------------------------------------------------
*1       Master    000a.000b.000c     15     V02     Ready
 2       Member    000d.000e.000f     14     V02     Ready
 3       Member    0010.0011.0012     13     V02     Ready

In this output, the asterisk (*) next to Switch 1 indicates it is the master switch of the stack.

3. `show version` Command

While show version doesn't explicitly state "stack," it can provide clues.

What to look for: In a stacked environment, the output of show version might mention "Switch N" where N is the stack member number, or indicate a "stack master" or "stack member" in the device description. If it's a standalone switch, it will typically just list "Switch" or its hostname without stack-specific numbering.

Physical Inspection

Visual cues can also help you determine if a switch is stacked:

Dedicated Stacking Ports: Look for specific stacking ports on the rear or side of the switch. These are often labeled "StackWise," "StackPort," or similar. They are typically different from regular Ethernet ports and might be larger or use specialized connectors.
Stacking Cables: If a switch is stacked, these dedicated ports will have special stacking cables connected between multiple switches. These cables are often short and robust, designed for high-bandwidth interconnectivity.
Stack Module (for modular switches): Some modular Cisco switches require a stacking module to be installed. Check if such a module is present.
LED Indicators: Some switches have dedicated stack-status LEDs that might indicate membership or master/member status. Consult your switch's documentation for specific LED behaviors.

Key Indicators Summary

Indicator	Standalone Switch	Stacked Switch
`show stack`	Command may not exist or shows no stack/single unit	Displays multiple units with roles (Master, Member)
`show switch`	Shows only one entry (Switch 1)	Shows multiple entries (Switch 1, Switch 2, etc.) with roles
`show version`	No stack-specific numbering (e.g., "Switch" only)	May show "Switch N" or indicate "stack master/member"
Stacking Ports	Present but unconnected, or not present	Utilized with dedicated stacking cables
Stacking Cables	Absent	Present, connecting multiple switches via stacking ports
Physical Placement	Units often distributed	Units typically physically grouped together, often in a single rack

By combining CLI commands with a quick physical check, you can definitively determine if your Cisco switch is part of a stack.