Cisco 350 Series Administration Manual page 150

Administration: Stack Management
Stack Changes
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
Connecting a New Unit
When a unit is inserted into the stack, a stack topology change is triggered. The unit ID is
assigned (in case of auto numbering), and the unit is configured by the master.
One of the following cases can occur when connecting a new unit to an existing stack:
• No duplicate unit IDs exist.
- Units with user-defined IDs retain their unit ID.
- Units with automatically-assigned IDs retain their unit ID.
- Factory default units receive unit IDs automatically, beginning from the lowest
available ID.
• One or more duplicate unit IDs exist. Auto numbering resolves conflicts and assigns
unit IDs. In case of manual numbering, only one unit retains its unit ID and the other(s)
are shutdown.
• The number of units in the stack exceeds the maximum number of units allowed. The
new units that joined the stack are shut down, and a SYSLOG message is generated
and appears on the master unit.
The following shows an example of auto numbering when a master-enabled unit joins the
stack. There are two units with unit ID = 1. The master selection process selects the best unit to
be the master unit. The best unit is the unit with the higher uptime in segments of 10 minutes.
The other unit is made the backup.
Auto-numbered Master-enabled Unit
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