Which switch stack selection master from ?

[athikom.ch]

Hi guy

I would like to know      Which switch stack is selection master from ? if it by default configure and it the same priority.

It selection from .. such as   uptime , mac address  whatever...

And i have any question about stacking

I have 2 switch  stack  one switch is master  and switch 2 is member   and  then I  reload switch 1  [master]   why  also both switch 2  reload.

[Flavio Miranda]

@athikom.ch

You can define the priority. Otherwise, it follows this rules:

1. The switch that is currently the stack master.

   Note: When stacks merge, the elected stack master would have been the master of one of the merged stacks.

   Note: When stacks partition, the stack master of the original stack will be the master of its partition.

2. The switch with the highest stack member priority value.

   Note: Cisco recommends that you assign the highest priority value to the switch that you prefer to be the stack master. This ensures that the switch is re-elected as stack master if a re-election occurs.

3. The switch that uses the non-default interface-level configuration.

4. The switch with the higher Hardware/Software priority. These switch software versions are listed from highest to lowest priority:

   1. Cryptographic IP services image software

   2. Noncryptographic IP services image software

   3. Cryptographic IP base image software

   4. Noncryptographic IP base image software

   Note: Switches that run Cryptographic or IP services image will take a longer time to load than Non-Cryptographic or IP base image. When you power on or reset an entire switch stack, some stack members will not participate in the stack master election. This is because stack members that are powered on within the same 20-second time frame participate in the stack master election and have a chance to become the stack master. Stack members that are powered on after the 20-second time frame do not participate in this initial election and only become stack members. At times, switches with lower software priority can become the stack master, but all stack members will participate in the stack master re-election.

5. The switch with the longest system up-time.

6. The switch with the lowest MAC address.

-If I helped you somehow, please, rate it as useful.-

[Bob Loblaw]

To answer the question when the switches are stacked they are logically considered to be ONE switch. Rebooting the master will cause the whole stack to reload. If you want to change the master you can change the priorities so that the switch you want to be Master has a higher priority than the current, then reload and it will elect the switch that you chose.

Hope this helps.

[Leo Laohoo]

Let's presume that the switches came out of a box.  The switches were NEVER powered on when the were rack-mounted and the stacking cables were connected.  

1.  Now the entire stack were powered up (for the first time) SIMULTANEOUSLY.  Because of this, there will be a stack election (of course) and the stack master will be elected based on the LOWEST MAC ADDRESS of the chassis.  

2.  If the stack was powered one-at-a-time (again, for the first time), then the first switch to get powered up will be the stack master.  

Once the stack election has been finalized, this will remain the same until someone manually re-configures the stacking order and/or stack election.