Stacking - D-Link xStack DGS-3426 User Manual

xStack DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch

Stacking

From firmware release v2.00 of this Switch, the xStack DGS-3400 series now supports switch stacking, where a set of twelve
switches can be combined to be managed by one IP address through Telnet, the GUI interface (web), the console port or through
SNMP. Each switch of this series has either two or three stacking slots located at the rear of the device, which can be used to add
10-gigabit DEM-410CX or DEM-410X stacking modules, sold separately. After adding these stacking ports, the user may connect
these ports together using copper or fiber stacking cables (also sold separately) in one of two possible topologies.
Duplex Ring – As shown in Figure 6-9, the Duplex Ring stacks switches in a ring or circle format where data can be transferred
in two directions. This topology is very resilient because if there is a break in the ring, data can still be transferred through the
stacking cables between switches in the stack.
Duplex Chain – As shown in Figure 6-10, The Duplex Chain topology stacks switches together in a chain-link format. Using this
method, data transfer is only possible in one direction and if there is a break in the chain, then data transfer will obviously be
affected.
Figure 6- 9. Switches stacked in a Duplex Ring
Within each of these topologies, each switch plays a role in the Switch stack. These roles can be set by the user per individual
Switch, or if desired, can be automatically determined by the switch stack. Three possible roles exist when stacking with the
xStack DGS-3400 series.
Primary Master – The Primary Master is the leader of the stack. It will maintain normal operations, monitor operations and the
running topology of the Stack. This switch will also assign Stack Unit IDs, synchronize configurations and transmit commands to
remaining switches in the switch stack. The Primary Master can be manually set by assigning this Switch the highest priority (a
lower number denotes a higher priority) before physically assembling the stack, or it can be determined automatically by the stack
through an election process, which determines the lowest MAC address. It will then assign that switch as the Primary Master, if all
priorities are the same. The Primary master is physically displayed by the seven segment LED to the far right on the front panel of
the switch where this LED will flash between its given Box ID and 'H'.
NOTE: Only ports 26 and 27 of the DGS-3427 support stacking. Port
25 cannot be used for stacking, and is to be used only as a 10-
Gigabit uplink port.
Figure 6- 10. Switches stacked in a Duplex Chain
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