Allied Telesis AT-S95 WEB - Manual (Page 235)

Managing Stacking
Configuring Stacking Management
Page 235
During the Warm Standby, the Master and the Secondary Master are synchronized with the static configuration
only. When the Stacking Master is configured, the Stacking Master must synchronize the Secondary Master. The
Dynamic configuration is not saved, for example, dynamically learned MAC addresses are not saved.
Each port in the stack has a specific Unit ID, port type, and port number, which are part of both the configuration
commands and the configuration files. Configuration files are managed only from the device Stacking Master,
including:
• Saving to the Flash
• Uploading configuration files to an external TFTP Server
• Downloading configuration files from an external TFTP Server
Whenever a reboot occurs, topology discovery is performed, and the Master learns all units in the stack. Unit IDs
are saved in the unit and are learned through topology discovery. If a unit attempts to boot without a selected
Master, and the unit is not operating in stand-alone mode, the unit does not boot.
Configuration files are changed only through explicit user configuration. Configuration files are not automatically
modified when:
• Units are added
• Units are removed
• Units are reassigned Unit IDs
• Units toggle between Stacking mode and Stand-alone mode
Each time the system reboots, the Startup configuration file in the Master unit is used to configure the stack. If a
stack member is removed from the stack and then replaced with a unit with the same Unit ID, the stack member is
configured with the original device configuration. Only ports which are physically present are displayed in the Web
Management Interface home page, and can be configured through the Web management system. Non-present
ports are configured through the CLI or SNMP interfaces.
Exchanging Stacking Members
If a stack member with the same Unit ID replaces an existing Unit ID with the same Unit ID, the previous device
configuration is applied to the inserted stack member. If the new inserted device has either more ports or less
ports than the previous device, the relevant port configuration is applied to the new stack member.
The Secondary Master replaces the Stacking Master if the following events occur:
• The Stacking Master fails or is removed from the stack.
• Links from the Stacking Master to the stacking members fails.
• A soft switchover is performed via the web interface or the CLI.
Switching between the Stacking Master and the Secondary Master results in a limited service loss. Any dynamic
tables are relearned if a failure occurs. The Running Configuration file is synchronized between the Stacking
Master and the Secondary Master, and continues running on the Secondary Master.
Configuring Stacking Management
The Stacking Page allows network managers to either reset the entire stack or a specific device. Device
configuration changes that are not saved before the device is reset are not saved. If the Stacking Master is reset,
the entire stack is reset. In addition, Unit IDs can be changed on the Stacking Page.
When configuring QoS for stacking, note that stacking only uses three queues.
To configure stack control:
1. Click Mgmt. Protocols > Stacking. The Stacking Page opens: