Master Recovery; No Backup; Stack Member Identification - IBM RackSwitch G8000 Application Manual

Master Recovery

No Backup

Stack Member Identification

152
RackSwitch G8000: Application Guide
If the prior Master recovers in a functioning stack where the Backup has assumed
stack control, the prior Master does not reassert itself as the stack Master. Instead,
the prior Master will assume a role as a secondary Backup to avoid further stack
disruption.
Upon stack reboot, the Master and Backup will resume their regular roles.
If a Backup is not configured on the active Master, or the specified Backup is not
operating, then if the active Master fails, the stack will reboot without an active
Master.
When a group of stacked switches are rebooted without an active Master present,
the switches are considered to be isolated. All isolated switches in the stack are
placed in a WAITING state until a Master appears. During this WAITING period, all
the network ports of these Member switches are placed into operator-disabled state.
Without the Master, a stack cannot respond correctly to networking events.
Each switch in the stack has two numeric identifiers, as follows:
• Attached Switch Number (asnum)
An asnum is automatically assigned by the Master switch, based on each
Member switch's physical connection in relation to the Master. The asnum is
mainly used as an internal ID by the Master switch and is not user-configurable.
• Configured Switch Number (csnum):
The csnum is the logical switch ID assigned by the stack administrator. The
csnum is used in most stacking-related configuration commands and switch
information output. It is also used as a port prefix to distinguish the relationship
between the ports on different switches in the stack.
It is recommended that asnum 1 and csnum 1 be used for identifying the Master
switch. By default, csnum 1 is assigned to the Master. If csnum 1 is not available,
the lowest available csnum is assigned to the Master.