Advanced Traffic Management Guide K/KA/KB.15.15

◦ Both fragments will have a Commander and a Standby selected (if there is more than
one switch in each fragment).
◦ When the stacking cable is reconnected to reform the chain:
– The Commander and Standby of the Active fragment retain those roles for the resulting
stack. If the original Commander was not in that fragment, then the stack will have
a new Commander when the stack is reformed.
– The switches in the Inactive fragment reboot and assume their new roles in the
reformed chain.
Replacing a failed stack member
If a Stack Member fails, the effect on the stack depends on which member failed.
• If the Commander fails, the Standby switch takes over as the Commander and one of the
Member switches in the stack is elected as the new Standby. All network ports and stacking
ports on the failed switch become non-operational.
• If the Standby fails, one of the Member switches in the stack is elected as the new Standby.
All network ports and stacking ports on the failed switch become non-operational.
• If a Member fails, all network ports and stacking ports on that switch become non-operational.
If a Stack Member fails:
1. Physically remove the Stack Member from the stack.
2. Replace the failed Stack Member.
NOTE: HP recommends using the same type (product or "J" number) switch as a replacement
since all configuration information is retained.
• If you are using the same type switch as a replacement:
1. Provision the new switch using the stacking member N command.
2. Reconnect all Ethernet ports as they were on the failed switch.
• If you are using a different type switch as a replacement:
1. Remove the failed switch from the stack configuration using the stacking member N
remove command.
2. Provision the new switch using the stacking member N command.
3. Reconnect Ethernet ports and create a new stack configuration on the new switch.
If the replacement switch uses a different version of software, it will be updated automatically to
match the software version running on the stack.
Replacing a failed stacking module
Replacing a failed stacking module is simpler than replacing a Stack Member since the switch
configuration itself does not change. In this case, there is no need to re-provision the switch as a
member of the stack. After you replace the stacking module, if the switch that experienced the
module failure was Commander or Standby, the election of a new Commander and Standby is
the same.
Merging stack fragments
When two fragments have the same stack-id, the merge of the fragments is almost always allowed
regardless of the merge policy. The Commander and Standby of the merged stack are selected
based on the election rules. All of the switches in the previously inactive fragment or fragments
reboot, and then join the Active fragment as Members.
Configuring a stack 297