Question 633 of 1,840
mediumMultiple ChoiceObjective-mapped
350-401 Practice Question: Examine the following configuration: interface…
Examine the following configuration:
interface Port-channel1 switchport mode trunk
!
interface GigabitEthernet0/1 switchport mode trunk channel-group 1 mode active spanning-tree portfast
!
interface GigabitEthernet0/2 switchport mode trunk channel-group 1 mode active spanning-tree portfast
What is the effect of the 'spanning-tree portfast' command on the member interfaces of this EtherChannel?
⚠ Common exam trap
Cisco often tests the misconception that STP features configured on physical interfaces are inherited by the EtherChannel, when in fact they are ignored and must be applied to the logical port-channel interface.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The PortFast on the member interfaces will be ignored because they are part of an EtherChannel.
When interfaces are configured as members of an EtherChannel, any spanning-tree configuration applied directly to the member interfaces (such as 'spanning-tree portfast') is ignored. Spanning-tree operates on the logical port-channel interface, not the individual physical members. Therefore, the PortFast command on GigabitEthernet0/1 and GigabitEthernet0/2 has no effect; instead, PortFast must be configured on the Port-channel interface itself to apply to the bundle.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The PortFast will be applied to the EtherChannel, causing it to immediately transition to forwarding.
Why it's wrong here
Incorrect. PortFast on member interfaces is not inherited by the port-channel; it must be applied to the port-channel interface.
- ✓
The PortFast on the member interfaces will be ignored because they are part of an EtherChannel.
Why this is correct
Correct. When interfaces are bundled into an EtherChannel, STP is handled at the port-channel level, and per-interface PortFast is overridden.
- ✗
The PortFast will cause the EtherChannel to form faster.
Why it's wrong here
Incorrect. PortFast does not affect EtherChannel formation; it affects STP state.
- ✗
The configuration will cause a spanning-tree loop because PortFast is used on trunk ports.
Why it's wrong here
Incorrect. While PortFast on trunks can be risky, in this case it is ignored, so no loop is created.
Visual reference
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Last reviewed: Jul 4, 2026
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