White Papers

Unplugged Stacking Cable
Problem: A stacking cable is unplugged from a member switch. The stack loses half of its bandwidth from the disconnected
switch.
Resolution: Intra-stack traffic is re-routed on another link using the redundant stacking port on the switch. A recalculation of
control plane and data plane connections is performed.
Master Switch Fails
Problem: The master switch fails due to a hardware fault, software crash, or power loss.
Resolution: A failover procedure begins:
1. Keep-alive messages from the master switch time-out after 60 seconds and the switch is removed from the stack.
2. The standby switch takes the master role. Data traffic on the new master switch is uninterrupted. The control plane
manages the Protocol traffic.
3. A member switch is elected as the new standby. Data traffic on the new standby is uninterrupted. The control plane
prepares for operation in Warm Standby mode.
Stack-Link Flapping Error
Problem/Resolution: Stacked switches monitor their own stack ports and disable any stack port that flaps five times within 10
seconds. If the stacking ports that flap are on the master or standby, KERN-2-INT error messages note the units.
To re-enable a downed stacking port, power cycle the stacked switch where the port is installed.
--------------------------------------MANAGMENT
UNIT-----------------------------------------
Error: Stack Port 48 has flapped 5 times within 10 seconds.Shutting down this stack port now.
Error: Please check the stack cable/module and power-cycle the stack.
10:55:20: %STKUNIT1-M:CP %KERN-2-INT: Error: Stack Port 52 has flapped 5 times within 10
seconds.Shutting down this stack port now.
10:55:20: %STKUNIT1-M:CP %KERN-2-INT: Error: Please check the stack cable/module and
power-cycle the stack.
---------------------------------------STANDBY
UNIT------------------------------------------
10:55:18: %STKUNIT1-M:CP %KERN-2-INT: Error: Stack Port 52 has flapped 5 times within 10
seonds.Shutting down this stack port now.
10:55:18: %STKUNIT1-M:CP %KERN-2-INT: Error: Please check the stack cable/module
and power-cycle the stack.
----------------------------------------MEMBER
2---------------------------------------------
Error: Stack Port 52 has flapped 5 times within 10 seconds.Shutting down this stack port
now.
Error: Please check the stack cable/module and power-cycle the stack.
Master Switch Recovers from Failure
Problem: The master switch recovers from a failure after a reboot and rejoins the stack:
● As a member unit if there is already a standby
● As a standby if there is no standby in the stack
Protocol and control plane recovery requires time before the switch is fully online.
Resolution: When the entire stack is reloaded, the recovered master switch becomes the master unit of the stack.
Stack Unit in Card-Problem State Due to Incorrect Dell Networking OS Version
Problem: A stack unit enters a Card-Problem state because the switch has a different Dell Networking OS version than the
master unit. The switch does not come online as a stack unit.
Resolution: The version mismatch case is taken cared of by firmware synchronization, which automatically upgrades the unit to
the required Dell Networking OS version. You do not have to manually upgrade the unit.
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Stacking