Configuration manual

0 throttles, 0 discarded, 0 collisions, 0 wredDrops
Rate info (interval 45 seconds):
Input 00.00 Mbits/sec, 0 packets/sec, 0.00% of line-rate
Output 00.00 Mbits/sec, 0 packets/sec, 0.00% of line-rate
Failure Scenarios
The following sections describe some of the common fault conditions that can happen in a switch stack
and how they are resolved.
Stack Member Fails
• Problem: A unit that is not the stack master fails in an operational stack.
• Resolution: If a stack member fails in a daisy chain topology, a split stack occurs. If a member unit
fails in a ring topology, traffic is re-routed over existing stack links.
The following syslog messages are generated when a member unit fails:
Dell#May 31 01:46:17: %STKUNIT3-M:CP %IPC-2-STATUS: target stack unit 4 not
responding
May 31 01:46:17: %STKUNIT3-M:CP %CHMGR-2-STACKUNIT_DOWN: Major alarm: Stack
unit 4 down - IPC
timeout
Dell#May 31 01:46:17: %STKUNIT3-M:CP %IFMGR-1-DEL_PORT: Removed port: Te
4/1-32,41-48, Fo 4/
49,53
Dell#May 31 01:46:18: %STKUNIT5-S:CP %IFMGR-1-DEL_PORT: Removed port: Te
4/1-32,41-48, Fo 4/
49,53
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.
Stacking
203