Users Guide

Table Of Contents

260 Stacking

If a new switch is added to a stack of switches that are powered and running

and already have an elected management unit in the stack, the newly added

switch becomes a stack member rather than the management unit in the

stack. Use the boot auto-copy-sw command on the management unit in the

stack to enable automatic firmware upgrade of newly added switches. If a

firmware mismatch is detected, the newly added switch does not fully join the

stack and holds until it is upgraded to the same firmware version as the

management unit in the stack. After firmware synchronization finishes, the

running configuration of the newly added unit is overwritten with the

configuration of the management unit in the stack. Stack port configuration

is always stored on the local unit and may be updated with preconfiguration

information from the management unit in the stack when the unit joins the

stack.

Information about a stack member and its ports can be preconfigured before

the unit is added to the stack. The preconfiguration takes place on the

management unit in the stack. If there is saved configuration information on

the management unit in the stack for the newly added unit, the management

unit in the stack applies the configuration to the new unit; otherwise, the

management unit in the stack applies the default configuration to the new

unit.

Removing a Switch from the Stack

Prior to removing a member from a stack, check that other members of the

stack will not become isolated from the stack due to the removal. Check the

stack-port error counters to ensure that a stack configured in a ring topology

can establish a communication path around the member to be removed.

The main point to remember when removing a unit from the stack is to

disconnect all the links on the stack member to be removed. Also, be sure to

take the following actions:

• Remove all the STP participating ports and wait to stabilize the STP.

• Remove all the member ports of any Port-Channels (LAGs) so there will

not be any control traffic destined to those ports connected to this member.

• Statically re-route any traffic going through this unit.

When a unit in the stack fails, the management unit in the stack removes the

failed unit from the stack. The failed unit reboots with its original running-

config. If the stack is configured in a ring topology, then the stack