Allied Telesis AT-S63 - Manual (Page 72)

Chapter 2: AT-9400Ts Stacks
72 Section I: Basic Operations
Discovery Process
When the switches of a stack are powered on or reset, they synchronize
their operating software in a two phase process before they begin to
forward network traffic through their ports.
In the first phase the switches initialize their AT-S63 Management
Software. It takes about one minute for a switch to fully initialize its
software.
In the second phase the switches determine the number of devices in the
stack, the cabling topology of the stacking modules, and, in the case of the
duplex-ring topology, the active path through the stacking modules. It is
also in this phase that the master switch of the stack is identified and the
parameter settings of the devices are configured with the commands in
the active configuration file in the master switch’s file system.
This second phase is referred to as the discovery process. The length of
time of the discovery process can vary depending on a number of factors,
like the number of switches in the stack, the switch models, and the
number and complexity of the commands in the active configuration file on
the master switch. For instance, a small stack of two switches might take
less than fifteen seconds to complete the discovery process, while a stack
of eight AT-9424Ts Switches might take several minutes.
When the discovery process is finished the switches of the stack begin to
forward network traffic from their ports.
A stack will perform both phases whenever the switches are powered on
or reset. However, a stack will automatically repeat the discovery phase
whenever there is change to its topology or composition. For example,
disconnecting a stacking cable from a stacking module, powering off a
switch, or adding or removing a switch from the stack are all examples of
events that will prompt a repetition of the discovery process.
Since the switches of a stack do not forward traffic during the discovery
process, a change to a stack’s topology will be disruptive to the activity of
your network. Consequently, changes to the composition of a stack should
be scheduled during periods of low network traffic to minimize the impact
on your network.