mediumMultiple Choice
CCNP 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 desirable
!
interface GigabitEthernet0/2 switchport mode access channel-group 1 mode desirable
What is the problem with this configuration?
⚠ Common exam trap
Cisco often tests the requirement that all EtherChannel member interfaces must have identical switchport modes (all trunk or all access), and candidates mistakenly think that the port-channel interface configuration overrides individual port settings or that the channel can form with mismatched modes.
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 switchport mode mismatch between Gi0/1 (trunk) and Gi0/2 (access) will prevent the EtherChannel from forming.
EtherChannel requires all member interfaces to have identical switchport modes (all trunk or all access). In this configuration, GigabitEthernet0/1 is configured as a trunk port while GigabitEthernet0/2 is configured as an access port. This switchport mode mismatch violates the EtherChannel consistency checks, preventing the logical bundle from forming. Cisco switches enforce this rule to ensure consistent VLAN tagging behavior across all links in 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 channel-group mode desirable is incompatible with trunk ports.
Why it's wrong here
PAgP desirable is a channel negotiation mode, not a VLAN or trunking parameter. Cisco trunk ports fully support PAgP, and desirable actively sends PAgP packets to try to form an EtherChannel with a peer. The real problem in this scenario is the Layer 2 interface inconsistency: Gi0/1 is trunk while Gi0/2 is access, which fails EtherChannel's consistency checks regardless of PAgP mode.
- ✗
The port-channel interface must also be configured as access to match Gi0/2.
Why it's wrong here
Configuring the port-channel interface as access would not fix the problem because the two physical members still disagree on their switchport mode. The port-channel interface acts as the logical bundle and propagates settings to member ports, but it cannot reconcile an existing trunk/access mismatch between Gi0/1 and Gi0/2. You would need to make Gi0/1 access as well, or change Gi0/2 to trunk, before the bundle can successfully form.
- ✓
The switchport mode mismatch between Gi0/1 (trunk) and Gi0/2 (access) will prevent the EtherChannel from forming.
Why this is correct
All physical ports in a Layer 2 EtherChannel must have identical switchport characteristics, including the switchport mode. Because Gi0/1 is configured as trunk and Gi0/2 as access, the ports fail the EtherChannel consistency check, so PAgP/LACP will not place both ports into a working bundle. Correcting the mode on both members to either trunk or access is mandatory before the port-channel interface can become operational.
- ✗
The EtherChannel will form but only Gi0/1 will be active.
Why it's wrong here
An EtherChannel does not simply choose one compatible member and leave the other out; the entire bundle fails when a configured member is incompatible. When Gi0/2 has a different switchport mode, the consistency check prevents the logical port-channel from coming up, so Gi0/1 cannot operate as a one-member active channel. The only way to get an active one-port bundle is to explicitly configure just that one port in the channel-group or to fix the mismatch, not to ignore the bad port.
Visual reference
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,923 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.