DES-3226S Layer 2 Fast Ethernet Switch User’s Guide
20
Stacking vs. Standalone Operation (Release 4.01)
By default, the Switch configuration settings allow it to operate as a standalone device, or in a stacked group. It is not
necessary to change any settings for the Switch to function in either capacity. However, it is useful to understand how the
stacking mode operates in the Switch and the effects if any this may have on configuration settings in a Switch when its
stacking status is changed.
Stacking mode is enabled by default and can be changed using the CLI command
config stacking mode
. If the Switch
has stacking mode enabled and is properly connected to other DES-3226S Switches, a negotiation takes place upon starting up
the Switches to determine how the Switch functions in the stack. For an all-DES-3226S stack, any time a change occurs in the
structure or composition of a stacked Switch group the entire stack will restart and the negotiation process begins anew. When
the stacking mode is disabled (
config stacking mode disable
), the Switch only allows standalone operation. If
stacking mode is disabled on a Switch, it should be disconnected from a stacked group.
NOTE:
The firmware for Release 4.01 allows stacking operation of the DES-3226S as a slave to the
DGS-3212SR and DGS-3312SR in a star topology. See the example below for more information.
Stacking mode can be changed using the CLI. When a DES-3226S Switch stack is first assembled, it is advisable to determine
which Switch will function as the master before placing the Switches in a rack and connecting them. If the Switch is used in a
stacked group with the DGS-3212SR or DGS-3312SR, the DGS-3x12SR series Switch operates as the master and the DES-
3226S Switches in the stacked group operate as slaves. The possible stacking configuration modes are as follows:
Enabled:
Stacking mode is enabled by default. When enabled the Switch can operate as a standalone device or it can operate
with other DES-3226S Switches in a properly connected stacked group. Stacking must be enabled for the Switch function in a
stacked arrangement with other DES-3226S Switches or with a DGS-3212SR High-Density Layer 2 or DGS-3312SR Layer 3
Gigabit Ethernet Switch.
Auto:
This is the default stacking mode setting for the DES-3226S. In auto stacking mode the Switch is eligible for stacking or
it can operate as a standalone device. If a DES-3226S Switch stack is connected and all units are configured to operate in auto
stacking mode, the master-slave relationships is determined automatically. For DES-3226S Switch stacks, the unit with the
lowest MAC address becomes the master (stack number 1). The order in which slave devices appear logically in the stack
(stack number 2+) is determined by how they are connected relative to the master Switch. The auto mode serves to first
determine if the device is stacked or standalone, then if stacked, it determines which Switch is the master and the remaining
stack numbers for the slave Switches.
Master:
The auto mode described above may be overridden so that a properly connected Switch in a stack may be forced into
master mode. Only one Switch in a stack may act as the master and all configuration settings for the stacked group - including
stacking configuration - are saved in configuration files in the master Switch. The stack is managed as a single entity through
the master. It may be convenient to place the master unit in the upper-most slot of a stacked group to visually distinguish it
form the slave units. The master unit should be used to uplink the stack group to the backbone. If the master unit fails or is
replaced for any reason, it is possible to load configuration files saved from the original master unit in order to continue
operation with identical settings. See the example below for a description of how to swap the master unit of a stacked group. A
Switch configured as the stack master will maintain this status regardless of any changes that occur in the composition of the
stacked group. If for example a connection to a slave unit or a connection between two slave units were to fail, the entire stack
will restart automatically. After restarting, the designated master unit retains its status.
Slave:
The auto mode may be overridden to force the Switch to operate in slave mode. When the Switch is in slave mode, it is
ineligible to function as a master and all configuration, is done through the master unit. A master Switch must be properly
connected to the stack for a Switch to operate in slave mode.
Disabled:
This forces the Switch to operate as a standalone device. In standalone mode the Switch functions as a standalone
device even if a stacking module is installed. To force standalone operation it is necessary to use the CLI command
config stacking mode disable
. A Switch that has stacking mode disabled should never connect to another Switch
through stacking ports.
NOTICE:
Do not use stacking ports on a Switch that has the stacking mode disabled.
Summary of Contents for DES-3226S
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