Administrator Guide

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 a 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 Aggregator 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.
Protocol traffic is managed by the control plane.
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 Aggregators 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 on which the port is installed.
The following is an example of the stack-link flapping error message.
--------------------------------------MANAGMENT
UNIT-----------------------------------------
Error: Stack Port 49 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 50 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 50 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.
Master Switch Recovers from Failure
• Problem: The master switch recovers from a failure after a reboot and rejoins the stack as the standby
unit or member unit. 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.
Stacking
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