Cisco Linksys SFE2000 Administration Manual page 22

Stack Master
The unit assigned the Unit ID number 1 serves as the Stack Master. All other units are stack
members. The Stack Master provides a single point of control, configuration and
management for the entire stack, and stores the configuration for all stack members.
(Members do not store any configuration information.)
Stack Backup Master
The unit assigned the Unit ID number 2 is a special stack member that serves as the stack
Backup Master. A stack Backup Master assumes the role of Stack Master for the remaining
stack members if the stack Master fails or is disconnected.
The Stack Master stores a copy of the active configuration on the Backup Master. This copy is
used only if the Backup Master assumes the role of Stack Master.
NOTE: Only the configuration file is copied. Any
dynamically-filled tables (for example, learned
addresses) are not copied from the Stack Master to the
Backup Master. If the Backup Master assumes the role of
Stack Master, it builds its own dynamic tables.
Stack Members
The units assigned the Unit IDs 3 through 8 are called stack members. A stack member
operates only as a member of the stack under the direction of an operational Stack Master
(or a Backup Master that has assumed the Stack Master role). Stack members are not
directly manageable and configurable, and must be managed through the Stack Master.
They do not contain any meaningful configuration information, including their own
configuration. If an operational Stack Master is not present and reachable, these units are
not functional.
Master-Enabled Units
Units that are assigned a Unit ID number of 1 or 2 are called master-enabled units. Only
master-enabled units participate in the Master Election process (see below) when they are
initialized, are inserted into a new stack, or lose connectivity with the existing Stack Master.
Only master-enabled units participate in the Master Election process and can become the
Stack Master or Backup Master. (Units that are assigned a Unit ID of 3 through 8 can only
16
Linksys One Ready Communications Solution
Chapter 3: Connecting the Switch
Understanding Advanced Stacking
3