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ccsoofficelan
Beginner

3750-X Stacking

Hi,

Currently i have the following settings :

Switch#  Role    Mac Address     Priority    Version     State

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

1       Member  d0d0.fd60.4580     1         1               Ready              

*2       Master   d0d0.fd61.5b80      2         1               Ready

now i need to add one omre (new) 3750 to the stack. The IOS versions and all are the same. I assume i have to first change the priroty value of the master to 15. But what would happen after this. Actually production systems are connected to the Master. When the priority value is changed would it reboot the master switch.???

Please advice anyone.

--hassan

1 ACCEPTED SOLUTION

Accepted Solutions

I confirm that you can keep 2 switches with priority 1 and the master with priority 2 or more. If the master fails, one of the members become master on base of mac-address, ios...etc...

See below all details of elecrion - re-election

Stack Master Election and Re-Election

The stack master is elected or re-elected based on one of these factors and in the order as listed:

1. The switch currently the stack master.

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

Is recommend assigning 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 not using the default interface-level configuration.

4. The switch with the higher priority switch version. The switch versions listed below are ordered

from highest to lowest priority:

1. Cryptographic EMI software

2. Noncryptographic EMI software

3. Cryptographic SMI software

4. Noncryptographic SMI software

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

6. The switch with the lowest MAC address.

A stack master retains its role unless one of these events occurs:

• The switch stack is reset.*

• The stack master is removed from the switch stack.

• The stack master is reset or powered off.

• The stack master has failed.

• The switch stack membership is increased by adding powered-on standalone switches or switch

stacks.*

In the events marked by an asterisk (*), the current stack master might be re-elected based on the listed

factors.

When you power on or reset an entire switch stack, some stack members might not participate in the

stack master election. Stack members that are powered on within the same 10-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 10-second time frame do not participate in this initial election and only

become stack members. All stack members participate in re-elections.

The new stack master becomes available after a few seconds. In the meantime, the switch stack uses the

forwarding tables in memory to minimize network disruption. The physical interfaces on the other

available stack members are not affected while a new stack master is elected and is resetting.

If a new stack master is elected and the previous stack master becomes available, the previous stack

master does not resume its role as stack master.

  Hope this helps

Pier

View solution in original post

5 REPLIES 5

  Hi Hassan,

if you add a new 3750 i can keep the same prioroty on the Master, infact the priority of master is 2 and if you add a new switch you will have the member 1 with priority 1 and the member 2 with priority 1. the master switch remain the master without need to reboot. If you want to change the priority on master you need to reload it.

Hi,

See the below link will help you in understanding...

While adding a Switch as a Slave to the Stack
While adding a Switch as a Master to the Stack
While adding a Provisioned Switch to a Switch Stack

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack3

Please rate the helpfull posts.
Regards,
Naidu.

so you mean i can keep adding switches with priority 1....

You can add maximum of 9 switches in a stack.

Sweta

P.S. Please rate the helpful answers.

I confirm that you can keep 2 switches with priority 1 and the master with priority 2 or more. If the master fails, one of the members become master on base of mac-address, ios...etc...

See below all details of elecrion - re-election

Stack Master Election and Re-Election

The stack master is elected or re-elected based on one of these factors and in the order as listed:

1. The switch currently the stack master.

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

Is recommend assigning 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 not using the default interface-level configuration.

4. The switch with the higher priority switch version. The switch versions listed below are ordered

from highest to lowest priority:

1. Cryptographic EMI software

2. Noncryptographic EMI software

3. Cryptographic SMI software

4. Noncryptographic SMI software

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

6. The switch with the lowest MAC address.

A stack master retains its role unless one of these events occurs:

• The switch stack is reset.*

• The stack master is removed from the switch stack.

• The stack master is reset or powered off.

• The stack master has failed.

• The switch stack membership is increased by adding powered-on standalone switches or switch

stacks.*

In the events marked by an asterisk (*), the current stack master might be re-elected based on the listed

factors.

When you power on or reset an entire switch stack, some stack members might not participate in the

stack master election. Stack members that are powered on within the same 10-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 10-second time frame do not participate in this initial election and only

become stack members. All stack members participate in re-elections.

The new stack master becomes available after a few seconds. In the meantime, the switch stack uses the

forwarding tables in memory to minimize network disruption. The physical interfaces on the other

available stack members are not affected while a new stack master is elected and is resetting.

If a new stack master is elected and the previous stack master becomes available, the previous stack

master does not resume its role as stack master.

  Hope this helps

Pier

View solution in original post