Cisco SGE2000 - - Gigabit Switch Administration Manual page 25

Managing Device Information
Managing Stacking
Cisco Small Business SFE/SGE Managed Switches Administration Guide
Factory Default Units
A unit in factory default mode has the following attributes:
•
Unit ID = 0. This setting indicates that the unit is in autonumbering mode.
•
Switch Operation Mode = Stack.
The combination of these two settings directs the system to automatically
configure the unit as a new stack member.
NOTE: A unit in stand-alone mode also displays Unit ID = 0.
Unit ID Validity Rules
Each member unit of a stack has a Unit ID that satisfies two conditions:
•
A Unit ID is a number from 1 to 8.
•
A Unit ID is unique within the stack.
Automatic Unit ID Assignment
Automatic Unit ID assignment is applied to Stack mode units with Unit ID of 0. This
includes factory default units as well as units whose Unit IDs are reset to 0 as a
result of Unit ID Conflict Resolution.
The Automatic Unit ID Assignment for units with Unit ID=0 proceeds as follows:
•
A Unit ID is assigned from the available valid, unique Unit IDs, starting with the
lowest available Unit ID.
•
If two or more units are queued to receive Unit IDs, the units are assigned Unit
IDs starting with the unit with the lowest MAC address.
Manual Unit ID Assignment
The system administrator can assign a specific, valid Unit ID to a stack member
manually. A Unit ID that is manually assigned is not subject to automatic numbering.
Manual numbering for stacking members is beneficial for providing a fast and easy
way of replacing stacking members. After a stack is initialized in factory default,
automatic numbering mode, the Unit IDs can be manually set to the same Unit IDs
assigned by automatic numbering. The system administrator can then configure
the switch ports. The port configuration of the switch is automatically stored in the
Stacking Master and Backup Master. If a stacking member must be replaced, an
identical replacement stacking member can be hot swapped into the running
stack. The hot swap can occur if the new stacking member is manually in the same
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