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CICSO 2960x switch stack - ensure a switch never changes its stack member number.

Posted on 2016-09-07
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Last Modified: 2016-09-25
Is it possible to ensure a switch always keeps its assigned stack member number?

I understand there is a master which is assigned 0, and each additional switch is assigned the lowest available stack number when it is added to the stack.

We have a script which automatically updates the vLAN on a port based on input to a webpage.

If the stack member number of a switch happened to change the script would begin making changes to the wrong switch – which would stuff everything up.

What for example would happen after a power failure if switch 1 & 2 failed to power-on? Would switches 3 & 4 then become 1 & 2.
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Question by:Andrew Josephson
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by:Rafael
Rafael earned 250 total points
ID: 41789372
Yes, there is and it goes by the Priority (1-15) setting of the switch.  So if you set it to 15 it will always be the master (hardware failure excluded) To start

First find out the stack  by entering

switch>show switch

It will give you something such as

Current
Switch#  Role      Mac Address     Priority     State
--------------------------------------------------------
 1       Slave     0016.4748.dc80     1         Ready
*2       Master    0016.9d59.db00     5         Ready

Notice that *2 is the Master as the priority is higher than it's peer.

To change it do the following:
1. Go to global configuration mode.
2.Issue the command
switch# switch current-stack-member-number renumber new-stack-member-number
3.Return to the privileged EXEC mode and reload the member with the command
switch#reload slot current-stack-member-number .
switch>show switch

You should now see it reversed of at the higher priority which ever your choose (1-15).

Here is a helpful article.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-2_2_e/stack_manager/configuration_guide/b_stack_ha_1522e_2960x_cg/b_stck_152ex_2960-x_cg_chapter_010.html

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html#anc10

HTH
-Rafael
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by:Andrew Josephson
Andrew Josephson earned 0 total points
ID: 41790531
Further clarification required pls -

My existing stack shows:

#show switch
Switch/Stack Mac Address : 009e.1e3a.1400
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
*1       Master 009e.1e3a.1400     1      4       Ready
 2       Member 005f.8627.7680     1      4       Ready
 3       Member 005f.8680.9d80     1      4       Ready
 4       Member 005f.869f.7e80     1      4       Ready

Open in new window

I need to power down the switch and relocate the stack.

If, for example, only switches  3&4 were  powered back up at the new location, a new master would be elected  - but would the switches retain their original switch number (ie 3 & 4) or become 1&2?
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Craig Beck earned 250 total points
ID: 41790561
Set the switch priority for the master (usually switch 1 if you go top-to-bottom) to 15 if you want it to always be the stack master.  Set subsequent switches with lower priorities.  For example...

switch 1 priority 15
switch 2 priority 13
switch 3 priority 11
switch 4 priority 9

Open in new window


That would mean that if switch 1 dies, switch 2 will become the master.  It won't renumber the ports though, so even if switch 1 dies, switch 2 will still have ports 2/0/1, etc.  That means you can still issue VLAN commands to ports on the correct switch no matter which switch is the master.
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Author Closing Comment

by:Andrew Josephson
ID: 41815133
Thank you
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