Stack Troubleshooting - SMC Networks TigerStack II SMC8848M Installation Manual

T
ROUBLESHOOTING

Stack Troubleshooting

If a stack fails to initialize or function, first check the following items:
• Check that all stacking cables are properly connected.
• Check if any stacking cables appear damaged.
• Check that only one Stack Master button is pressed in.
• Check that all switches in the stack are powered on.
After checking all items, reboot all the switches in the stack.
Switches in the stack may be configured using a ring- or line-topology. To
ensure minimal disruption in case a unit or stacking cable fails, always use a
ring-topology. When using ring-topology configuration and a switch fails,
or a stacking cable is disconnected, the stack continues normal operation
using line-topology stacking through the remaining stack connections.
If any changes occur to a slave unit, such as unit failure or insertion of a
new unit, operation of the other units in the stack are not affected. On the
other hand, if the master unit fails, the unit with the lowest MAC address is
elected as the new master. The stack reboots, discovers the new stack
topology, assigns identifiers to each unit, and checks the software images
on each unit. This process make take up to two minutes.
If you do not connect a wrap-around cable from the bottom unit back up
to the top unit in the stack, the failure of a single unit will cause the stack to
break into two separate stacks. In this case, a master unit will be elected for
both of the stacks. However, backup information inherited from the
previous master unit will cause the same IP address to be used by both
master units in the two stacks. You must therefore manually reconfigure
the IP address of the management interface on one of the master units.
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