350-401 Question 132
Select 4A network engineer is troubleshooting an EtherChannel issue between two switches. The EtherChannel is configured using LACP. On one switch, the EtherChannel interface is in 'suspended' state. Which of the following could be the root cause of the issue?
- A
The port-channel mode is mismatched between the two switches.
- B
One or more physical interfaces in the EtherChannel are configured with different VLANs.
- C
The switch ports on one side of the EtherChannel are configured as access ports, while the other side is configured as trunk ports.
- D
The LACP system priority is not set to the same value on both switches.
- E
One of the physical interfaces in the EtherChannel is administratively shut down.
Show answer and explanation
Correct answers: A, B, C, E
Explanation
When troubleshooting static or dynamic EtherChannels, it is crucial to ensure that all participating interfaces have consistent configurations, including VLANs, port types (trunk/access), and operational status. LACP requires matching configurations for negotiation to succeed. The LACP system priority, however, is unrelated to the formation of the EtherChannel and does not need to match between switches.
- A. Correct.
Mismatched port-channel mode could cause LACP to fail and place the EtherChannel in a 'suspended' state.
- B. Correct.
All physical interfaces participating in the EtherChannel must have identical configurations, including VLANs. A mismatch can cause the EtherChannel to not form.
- C. Correct.
Access and trunk configurations must match on both sides of the EtherChannel. A mismatch can result in the EtherChannel failing to operate correctly.
- D. Incorrect.
LACP system priority does not need to match between switches. It is used to determine which switch is the master for LACP negotiations, but it will not cause the EtherChannel to fail.
- E. Correct.
If one of the physical interfaces in the EtherChannel is administratively shut down, the EtherChannel will not come up and may be placed in 'suspended' state.