stack priority

[suthomas1]

Hello All,

We have an existing 3750 serving the users in layer 2 configuration. Another 3750 is to be added as stacked switch to this.

from current switch:

Switch#  Role      Mac Address     Priority     State

--------------------------------------------------------

*1       Master    002c.2d5b.6a00     1         Ready

If the existing switch is the master, do i need to change or configure  any priority related thing on the new switch to be stacked? I think one with highest priority (15)

will take over as master.

please help..thanks.

[smogra]

Hi,

This document might interest you:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack4

If the new switch has to be added as a master, then

Change the priority value of the switch to be added to a value  greater than the highest priority of the stack. Highest being 15.

switch priority

[walter.rojas]

If I have the following considering Cisco 3650-24-PS and PD

Switch 1 priority 15 

Switch 2 priority 10 my upling is here TenGig2/1/3 and I want to convert this to be Te1/1/3, in other words I wan to convert switch 2 in 1.

switch 1 renumber 3

switch 1 priority 8

switch 2 renumber 1

switch 2 priority 15

switch 3 renumber 2

Doing that, I'll loose all interfaces configurations in the current interfaces Gi1/0/1-24?

[Somasundaram Jayaraman · Accepted solution]

HI,

let us say there are two switches A & B.

A is having the priority of 9

B is having the priority of 8

If  we want to add another switch in the stack, check the priority of the  switch before joining. It should not be greater than 9. If it is greater  than 9 then it will become the master after we issue the reload.

++ Also the stack master election will take place only if the reload is issued from the master switch.

++ unless and until you reload the entire stack, the priority wont take effect eventhough it is configured on the switch.

Hope this answers your query.

Cheers

Somu

Pls rate helpful answers.

[Joseph W. Doherty]

As noted by the other posters, the current 3750 master isn't preempted just because you add another switch to the stack. Master priority only comes into play when there's a need for a new master (such as a stack reload, which isn't required to add the stack member).

That said, note if the newly added switch has a higher priority, it should become stack master upon the next stack election (which you may, or may not be, desired).

Also note, if switch members stack priority is the same, there's other criteria for determining the stack master.

Normally, you want to also insure the same IOS version is being used on all stack members, ideally with the same feature set, neither is always required on the 3750, but such differences can cause some "issues".

Lastly, you need to be careful about the config of the to be added switch, assuming you don't want it's config to possibly be the combined stack config.

Suggest you review the 3750 config guides for your IOS version. They should (I recall?) have whole chapter devoted to stack maintenance.