Number assignation of new member in a stack

[Telecom Team]

Hi, 

I have a stack of 3 switch (Catalyst 9300) and they are numbering as

Switch 1 (master priority 15),

Switch 2 (priority 10)

Switch 4 (default priority)

What happen if i add a new switch out-of-the box without configuration provisioning ? will he have the number 3 or 5 ?

do we need to pre-provision switch 3 number before ?

thanks for your help

[luis_cordova]

Hi @Telecom Team ,

Check what this guide indicates

Stack Member Numbers

The stack member number (1 to 8) identifies each member in the switch stack. The member number also determines the interface-level configuration that a stack member uses. You can display the stack member number by using the show switch EXEC command.

A new, out-of-the-box switch (one that has not joined a switch stack or has not been manually assigned a stack member number) ships with a default stack member number of 1. When it joins a switch stack, its default stack member number changes to the lowest available member number in the stack.

Stack members in the same switch stack cannot have the same stack member number. Every stack member, including a standalone switch, retains its member number until you manually change the number or unless the number is already being used by another member in the stack.

• If you manually change the stack member number by using the switch current-stack-member-number renumber new-stack-member-number EXEC command, the new number goes into effect after that stack member resets (or after you use the reload slot stack-member-number privileged EXEC command) and only if that number is not already assigned to any other members in the stack. Another way to change the stack member number is by changing the SWITCH_NUMBER environment variable.

  If the number is being used by another member in the stack, the switch selects the lowest available number in the stack.

  If you manually change the number of a stack member and no interface-level configuration is associated with that new member number, that stack member resets to its default configuration.

  You cannot use the switch current-stack-member-number renumber new-stack-member-number EXEC command on a provisioned switch. If you do, the command is rejected.

• If you move a stack member to a different switch stack, the stack member retains its number only if the number is not being used by another member in the stack. If it is being used, the switch selects the lowest available number in the stack.

• If you merge switch stacks, the switch that join the switch stack of a new active switch select the lowest available numbers in the stack.

As described in the hardware installation guide, you can use the switch port LEDs in Stack mode to visually determine the stack member number of each stack member.

You can enter the Stack mode on any of these switches by pressing the mode button. Based on the switch number configured on each switch, the corresponding port LED will be blinking green. For instance, if the switch number configured on a particular switch is three, then the port LED-3 will be blinking green when the mode button is set to stack.

This is the link

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-5/configuration_guide/stck_mgr_ha/b_165_stck_mgr_ha_9300_cg/managing_switch_stacks.html

Regards

[Telecom Team]

thansk.

But i've a doubt...

I read this configuration guide but My question is whether it will take the smallest available but in my case the number 3 has never been used and the number 5 either.

So does he take the smallest number that follows the last member of the stack (in my case the smallest member is number 4 then it would be 5 for the next ?) or does he complete the series with number 3 ?

[luis_cordova]

Hi @Telecom Team ,

My suggestion is:
First try to change switch number 4 to number 3.

If you manually change the stack member number by using the switch current-stack-member-number renumber new-stack-member-number EXEC command, the new number goes into effect after that stack member resets (or after you use the reload slot stack-member-number privileged EXEC command) and only if that number is not already assigned to any other members in the stack.

With this, you can check if, for any error, it is detecting number 3 as busy.
If you can change the switch number, theoretically the next connected switch should be at number 4.

About your doubt:

So does he take the smallest number that follows the last member of the stack (in my case the smallest member is number 4 then it would be 5 for the next ?) or does he complete the series with number 3 ?

The guide says:

If the number is being used by another member in the stack, the switch selects the lowest available number in the stack.

Currently, you have occupied the numbers 1,2 and 4, so the new switch should, in theory, occupy the number 3 (the lowest).
But, if by some error the number 3 is detected as busy, the new switch should be in number 5.

Remember to mark the correct answers as solved, because that helps other users with similar doubts.

Regards

[Telecom Team · Accepted solution]

Hi,

I confirm that the switch will get the number 3.

i made the test this morning.

Thanks