Administration: Stack Management
Software Auto Synchronization in Stack
Cisco 350XG & 550XG Series 10G Stackable Managed Switches
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Slave Unit Handling
While the backup becomes the master, the active slave units remain active and
continue to forward packets based on the configuration from the original master.
This minimizes data traffic interruption in units.
After the backup unit has completed the transition to the master state, it initializes
the slave units one at a time by performing the following operations:
•
Clear and reset the configuration of the slave unit to default (to prevent an
incorrect configuration from the new master unit). As a result, there is no
traffic forwarding on the slave unit.
•
Apply related user configurations to the slave unit.
•
Exchange dynamic information such as port STP state, dynamic MAC
addresses, and link up/down status between the master and the slave unit.
Packet forwarding on the slave unit resumes after the state of its ports are
set to forwarding by the master according to STP.
NOTE
Packet flooding to unknown unicast MAC addresses occurs until the
MAC addresses are learned or relearned.
Reconnecting the Original Master Unit After Failover
After failover, if the original master is connected again, the master selection
process is performed. If the original master (unit 1) is reselected to be the master,
the current master (unit 2, which was the original backup unit) is rebooted and
becomes the backup once again.
NOTE
During master/backup failover, the up time of the backup unit is retained.
Software Auto Synchronization in Stack
All the units in the stack must run the same software version (firmware and
bootcode). Each unit in a stack automatically downloads firmware and bootcode
from the master unit if the firmware and/or boot code that the unit and the master
are running is different. The unit automatically reboots itself to run the new version.
