Cisco Stack Wise Port numbering and identify exact switches

[gayansa.samarakoon]

Dear All,

I have few questions regarding Cisco stack wise technology.

1. Once stack is built based on which criteria interface numbering is decided? If we restart the devices randomly again without changing the default priority values, will the interface numbers will be changed?

2. I know by issuing "Show Switch" command  we can get the MAC addresses and their role (Active, Standby, Member). But if we are doing a remote configuration how can we identify to which switch  are we doing the configuration. For instance - We can remotely logged into the stack using SSH/Telnet and local person have no idea about the stack numbers and only knows the physical port that the device is connected.(Physical port 1/0/23 could be selected as 3/0/23 in the stack).

Really appreciate if someone can help me the doubts.

Thank You,

Gayan

[M02@rt37]

Hello @gayansa.samarakoon,

Interface numbering in a Cisco Stackwise stack is based on the stack member number followed by the interface number on that member. For example, if you have a stack of three switches, the interface numbering might look like this: 1/0/1, 2/0/1, 3/0/1. The stack member number is assigned based on the priority and role within the stack. The switch with the highest priority becomes the stack master and is usually assigned member number 1. Other switches in the stack get subsequent numbers.

If you restart the devices without changing the priority values, the interface numbers typically won't change, as long as the stack topology remains the same.

To identify which physical switch in a stackwise stack you are configuring remotely based on a physical port, you can use the show switch command in the stack. The show switch command provides information about each switch member in the stack, including its role (Active, Standby, or Member), and its stack member number. Log in to the Switch and identify which switch has the specific port (e.g., 3/0/1) and note its stack member number. 

This way, you can determine the target switch based on the physical port and ensure you are configuring the correct interface within the stack.

[gayansa.samarakoon]

Dear M02@rt37 ,

As far as I can remember if we console into a switch of the switch stack, and if we issue "Show switch" command. The output of "Show switch" command will show the switch , the console cable is connected with * before switch name.

Incase of Telnet/SSH how can we trace stack member number with physical switch. Since Switch stack has got one management IP. In the internet I saw some posts that we can login to individual switches using their member number.

Please assist me on this.

Thank You,

Gayan

[M02@rt37]

Hello @gayansa.samarakoon,

Depend of the model:

Do #show switch detail

This command will display information about each stack member, including its IP address or hostname. Once you have identified the IP address of the specific member switch you want to connect to, you can use it to establish a Telnet or SSH session directly to that switch.

[Joseph W. Doherty]

Interface numbering is prefixed by stack member number.

Stack member number, I recall, is independent of priority number, and is "locked" to a physical unit, although (with some work) it can be changed.

I recall (?) some stacks have a command to flash LEDs of a specific stack member.  But, I've found stack member might be identified by telling remote person to look for switch with specific ports up/down, number of ports, port types, etc.

BTW, for stacked switches, labeling device name and member number helps.