Unit Failure In Stack - Cisco 350 Series Administration Manual

8

Unit Failure in Stack

125
The following shows what happens when a user-assigned, master-enabled unit with Unit ID 1
joins a stack that already has a master unit with user-assigned unit ID 1. The newer Unit 1 does
not join the stack and is shutdown.
User-assigned Master-enabled Unit
This section includes the following topics:
• Failure of Master Unit
• Master/Backup Switchover
• Slave Unit Handling
• Reconnecting the Original Master Unit After Failover
Failure of Master Unit
If the Master fails, the backup unit takes over the master role and continues to operate the stack
normally.
For the backup to be able to take the place of the master, both units maintain a warm standby at
all times. In warm standby, the master and its backup units are synchronized with the static
configuration (contained in both the Startup and Running configuration files). Backup
configuration files are not synchronized. The backup configuration file remains on the
previous master.
Dynamic process-state information, such as the STP state table, dynamically-learned MAC
addresses, dynamically-learned Smartport types, MAC Multicast tables, LACP, and GVRP are
not synchronized.
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
Administration: Stack Management
Unit Failure in Stack