Stacking Device Table - D-Link xStack Reference Manual

xStack® DGS-3120 Series Layer 2 Stackable Managed Switch Web UI Reference Guide
Synchronization State – Once the Primary Master and the Backup Master have been established, the Primary Master
will assign Stacking Unit IDs to switches in the stack, synchronize configurations for all switches and then transmit
commands to the rest of the switches based on the users configurations of the Primary Master.
Once these steps have been completed, the switch stack will enter a normal operating mode.
Stack Switch Swapping
The stacking feature of the Switch supports "hot swapping" of switches in and out of the running stack. Users may
remove or add switches to the stack without powering down or largely affecting the transfer of data between switches
in the stack, with a few minor provisions.
When switches are "hot inserted" into the running stack, the new switch may take on the Primary Master, Backup
Master or Slave role, depending on configurations set on the newly added switch, such as configured priority or MAC
address. Yet, if adding two stacks together that have both previously undergone the election process, and therefore
both have a Primary Master and a Backup master, a new Primary Master will be elected from one of the already
existing Primary Masters, based on priority or MAC address. This Primary Master will take over all of the Primary
Master's roles for all new switches that were hot inserted. This process is done using discovery packets that circulate
through the switch stack every 1.5 seconds until the discovery process has been completed.
The "hot remove" action means removing a device from the stack while the stack is still running. The hot removal is
detected by the stack when it fails to receive heartbeat packets during its specified interval from a device, or when one
of the stacking ports links is down. Once the device has been removed, the remaining switches will update their
stacking topology database to reflect the change. Any one of the three roles, Primary Master, Backup Master or Slave,
may be removed from the stack, yet different processes occur for each specific device removal.
If a Slave device has been removed, the Primary Master will inform other switches of the hot remove of this device
through the use of unit leave messages. Switches in the stack will clear the configurations of the unit removed, and
dynamically learned databases, such as ARP, will be cleared as well.
If the Backup Master has been hot removed, a new Backup Master will be chosen through the election process
previously described. Switches in the stack will clear the configurations of the unit removed, and dynamically learned
databases, such as ARP, will be cleared as well. Then the Backup Master will begin backing up the Primary Master
when the database synchronization has been completed by the stack.
If the Primary Master is removed, the Backup Master will assume the Primary Master's role and a new Backup Master
will be chosen using the election process. Switches in the stack will clear the configurations of the unit removed, and
dynamically learned databases, such as ARP, will be cleared as well. The new Primary Master will inherit the MAC and
IP address of the previous Primary Master to avoid conflict within the stack and the network itself.
If both the Primary Master and the Backup Master are removed, the election process is immediately processed and a
new Primary Master and Backup Master is determined. Switches in the stack will clear the configurations of the units
removed, and dynamically learned databases, such as ARP, will be cleared as well. Static switch configurations still
remain in the database of the remaining switches in the stack and those functions will not be affected.
NOTE: If there is a Box ID conflict when the stack is in the discovery phase, the device will enter

Stacking Device Table

This window is used to display the current devices in the Switch Stack.
To view this window, click System Configuration > Stacking > Stacking Device, as shown below:
a special standalone topology mode. Users can only get device information, configure
Box IDs, save and reboot. All stacking ports will be disabled and an error message will be
produced on the local console port of each device in the stack. Users must reconfigure
Box IDs and reboot the stack.
Figure 2-25 Stacking Device Table window
24