DES-3226S Layer 2 Fast Ethernet Switch User’s Guide
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For DES-3226S Switch stacks, changes made to the composition of a Switch stack group, that is, adding new Switches or
taking Switches out of the stack, require all Switches to restart. The new stacking order is negotiated to reflect the changes
made to the group. If the master Switch has been configured to force master status it retains this status, likewise Switches
forced to operate in slave mode retain the status after restarting. The restart occurs automatically if any stacking link is
disconnected.
For star topology arrangements, the DGS-3212SR or DGS-3312SR does not restart when a link or Switch failure occurs. Only
the effected Switch will restart if its link to the DGS-3x12SR series Switch fails. The remaining DES-3226S Switches continue
to operate as before.
The command show stacking can be used to view stacking information. If stacking has been disabled, the stacking mode will
be listed as Standalone.
Managing Switch Stacks
Multiple DES-3226S Switches equipped with stacking modules may be connected in a stacking arrangement so that up to eight
Switches are managed as a single unit with a single IP address. The Release 4.01 DES-3226S can connect to the DGS-3212SR
or DGS-3312SR via the stacking port in a star topology. Up to eight Switches may be connected to the DGS-3x12SR and be
managed as a slave device through the DGS-3x12SR series Switch.
The default stacking mode will establish a master Switch for the stack through a negotiation process that takes place when all
devices are started up. In a DES-3226S stack, the Switches negotiate the master-slave relationship. Once the master Switch is
determined, the remaining Switches function as slaves. The stack number of the slave Switches is determined by where it is
actually positioned in the stack. This can be taken into account when you are placing the Switches in an equipment rack.
For star topology stacking arrangements with the DGS-3212SR or DGS-3312SR, the default settings of the DES-3226S assign
slave status and the unit number is determined by the number of the port connected at the other end of the stacking connection.
Keep in mind the following important considerations for stacked Switch groups:
•
All management of the Switches in the stack is done through the master Switch.
•
The master Switch should be used to uplink to the Ethernet backbone.
•
For DES-3226S stacks, the master Switch can be chosen automatically as each Switch in a connected stack competes
for status. However, you can choose a specific device and force it to operate as the master. Use the CLI command
config stacking mode enabled master
for the selected Switch; leave the remaining Switches in the
default auto-stacking mode.
•
For DES-3226S stacks, if the link between any two Switches fails or is disconnected, or if any Switch in a stacked
group fails, all of the Switches in the stack will automatically reboot. Since the stack is connected as a ring, the stack
will need to be connected to work around the failed link. Change the cabling to bypass the failed link and allow the
stack to reboot. The Switches will negotiate again since the composition of the stack has been altered. Read below for
more information about changes in stacked Switch groups.
•
A Switch stack has a single IP address
−
if the stacking link to a given Switch fails or is disconnected, that Switch will
loose its status in the stack and reboot as a standalone device with the IP settings it had before becoming a member of
the Switch stack.
NOTE:
For Release 4.01 the DES-3226S maintains two separate configurations, one for standalone
operation and another for stacked operation. Each configuration has identical IP settings, VLANs, link
aggregation, QoS, etc. This dual system allows a Switch to change status from standalone to stacking
enabled and keep its configuration settings.
Changes to Switch Stack Structure
If Switches are added to or taken out of a stacked group of DES-3226S Switches it is necessary to change the composition of a
Switch stack and rearrange the stacking connections. If a stacking link fails or if a member of a stacked group fails, the
composition of the stack will necessarily change also. In such a case intervention is required to at least reconnect the stacking
cable to bypass the failure. In addition to making changes to the cable links connecting the Switches in the stack, it may be
necessary or desirable to change the stacking mode configuration of one or more units. A few examples presented below to
help make the changes to cable connections for DES-3226S stacks and if necessary, to Switch stacking mode configuration
settings.
Summary of Contents for DES-3226S
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