Cisco Linksys SFE2000 Administration Manual page 34

the group, the scenario described in "Replacing a Failed Stack Master Unit in an
Operational Stack" applies.
NOTE: If the stack is split in two groups, one with the
Stack Master and one with the Backup Master, both
groups will function.
The Master Discovery, Master Election and Unit ID Allocation & Duplicate Unit ID Conflict
Resolution processes occur with the following results:
• If the Stack Master unit remains in the split stack, the Stack Master discovers (using
the Master Discovery process) that the Master Backup unit no longer responds. The
Stack Master notifies the system administrator (using SYSLOG messages and SNMP
traps) of the removed units and ports that belong to the unreachable units and they
are reported as "not present."
• If the Backup Master unit remains in the split stack, the Backup Master determines
this as a case of Stack Master failure and takes over and manages the remaining
units as a stack while keeping its previous Unit ID number. Because the Backup
Master was not acting as a master prior to the split, it initiates a topology database
and ports learning process. Traffic might be halted for a short period of time until
synchronization (unit and port configuration) is completed. New units discovered by
the Backup Master notify the system administrator (using SYSLOG messages and
SNMP traps).
• The partial stacks both continue to work as they did previously, but with fewer units.
• No unit ID changes are performed in each of the partial stacks.
• If each part of the stack has a Stack Master (for example, one contains the original
Stack Master, and one contains the Backup Master), and are operating as two
separate stacks, both Stack Masters contain the same configuration and use the
same IP address.
NOTE: If both Stack Masters use the same IP Address,
problems can occur on the network, because users
cannot connect to one of the stacks through its IP address.
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Linksys One Ready Communications Solution
Chapter 3: Connecting the Switch
Stack Troubleshooting and Maintenance
3