Stacking Actions - Allied Telesis AT-8100L/8 User Manual

Chapter 21: Hardware Stacking

Stacking Actions

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This phase may take from just a few seconds to up to a minute, depending
on the size of the stack, and the number and complexity of the commands
in the file.
The switches of the stack begin to forward network traffic at the
completion of the fifth phase.
The stack performs all of the phases when the switches are powered on or
reset. The discovery phase is repeated if a switch is added or removed
from the stack.
For further information about the initialization processes and instructions
on how to monitor them, refer to the 8100S Series Stacking Installation
Guide.
Here are the actions of an active stack when a master or member switch is
removed:
 If the stack has only two switches, and you remove or power off
one of the units, the remaining switch automatically resets as a
stand-alone device.
 If the master switch of a stack of three of more units is removed or
powered off, the member switch with the lowest ID number of the
remaining devices automatically assumes the role as the master
switch of the stack. The remaining switches retain their
configuration settings, and there is no interruption of the forwarding
of Layer 2 packets from the remaining switches.
Here are the actions of an active stack when a new switch is added:

If the ID number of the new member switch is higher than the
numbers of the existing switches, the master switch waits for the
new unit to initialize its management software and afterwards
checks the version number of the software against its own
software. If the new unit has a different version, the master switch
downloads its software to the new unit.
 If the ID number of the new member switch is lower than the ID
number of the current master switch, a message is displayed on all
of the active local and remote management sessions. You may
use the message to designate the new member switch as the new
master switch of the stack. If you respond with yes, the stack
resets, the new member becomes the new master switch, and the
previous master switch is reassigned the next available ID number.
If you respond with no, or if there is no response to the message
after 30 seconds, the new member is reassigned the next available
ID number.