Lab Simulation 41 Guidelines This is a lab item in which tasks will be performed on virtual devices. - Refer to the Tasks tab to view the tasks for this lab item. - Refer to the Topology tab to access

This lab simulation tests the ability to configure 802.1Q trunking and IEEE 802.3ad LACP EtherChannel on Cisco-like switches to enable inter-VLAN communication across the trunk link.

Submitted by haruto_sh· Mar 5, 2026Network Access

Question

Lab Simulation 41 Guidelines This is a lab item in which tasks will be performed on virtual devices. - Refer to the Tasks tab to view the tasks for this lab item. - Refer to the Topology tab to access the device console(s) and perform the tasks. - Console access is available for all required devices by clicking the device icon or using the tab(s) above the console window. - All necessary preconfigurations have been applied. - Do not change the enable password or hostname for any device. - Save your configurations to NVRAM before moving to the next item. - Click Next at the bottom of the screen to submit this lab and move to the next question. - When Next is clicked, the lab doses and cannot be reopened. Topology Tasks Task 1: Configure trunks between Sw1 and Sw2 on ports E0/0 and E0/1 using the IEEE standard frame tagging method. - Add the IT_User_VLAN as the untagged VLAN to the trunk. - Allow only the untagged VLAN and VLANs 20 and 40 on trunks. - Verify that PC1 pings PC2 and PC3 pings PC4. Task 2: On Sw1 and Sw2, use IEEE 802.3ad link aggregation. - Assign number 10 to the link. - Combine E0/0 and E0/1 into a single logical link. - Ensure Sw2 does not negotiate but responds to negotiation requests. Answer: See the below explanation

Exhibits

Explanation

This lab simulation tests the ability to configure 802.1Q trunking and IEEE 802.3ad LACP EtherChannel on Cisco-like switches to enable inter-VLAN communication across the trunk link.

Approach. The core of this lab requires configuring EtherChannel (link aggregation) and 802.1Q trunking (VLAN tagging) simultaneously on the logical Port-channel interface between Sw1 and Sw2. The tasks are performed on both Sw1 and Sw2 using a Cisco IOS-like command-line interface.

General steps for both Sw1 and Sw2 (assuming Cisco IOS syntax):

Access the console for Sw1 and Sw2.
Enter privileged EXEC mode (enable).
Enter global configuration mode (configure terminal).

Task 2: Configure IEEE 802.3ad Link Aggregation (LACP) for Port-channel 10 This involves bundling interfaces e0/0 and e0/1 into a single logical link, Port-channel 10, using LACP. Sw1 will be active and Sw2 will be passive as per the requirement for Sw2 not to negotiate but respond.

On Sw1:

interface range ethernet 0/0 - 0/1
  channel-group 10 mode active  // Assigns interfaces e0/0 and e0/1 to Port-channel 10, actively initiating LACP negotiation
  no shutdown                   // Ensures the physical interfaces are up
  exit

On Sw2:

interface range ethernet 0/0 - 0/1
  channel-group 10 mode passive // Assigns interfaces e0/0 and e0/1 to Port-channel 10, passively waiting for LACP negotiation
  no shutdown                   // Ensures the physical interfaces are up
  exit

Task 1: Configure Trunks (IEEE 802.1Q) on the Port-channel

Note: Trunking configurations must be applied to the logical Port-channel interface (Port-channel 10), not the individual physical interfaces, once the EtherChannel is formed. The 'IT_User_VLAN' is designated as the untagged VLAN; without a specified ID, it is typically assumed to be VLAN 1, the default native VLAN on Cisco devices. We will configure VLAN 1 as the native VLAN and ensure it's allowed along with VLANs 20 and 40 on the trunk.

On Sw1 (after configuring channel-group):

interface Port-channel 10
  switchport mode trunk                   // Enable 802.1Q trunking on the logical interface
  switchport trunk encapsulation dot1q    // Explicitly set 802.1Q encapsulation (good practice, though often default for trunk mode)
  switchport trunk native vlan 1          // Set VLAN 1 (IT_User_VLAN) as the untagged/native VLAN
  switchport trunk allowed vlan 1,20,40   // Allow only native VLAN 1 and VLANs 20, 40 on the trunk
  no shutdown
  exit

On Sw2 (after configuring channel-group):

interface Port-channel 10
  switchport mode trunk
  switchport trunk encapsulation dot1q
  switchport trunk native vlan 1
  switchport trunk allowed vlan 1,20,40
  no shutdown
  exit

Final Steps for both Sw1 and Sw2:

end
write memory // Save the configuration to NVRAM as per guidelines, crucial for retaining changes

Verification (as per Task 1):

From PC1, ping PC2 (10.2.2.20). This tests connectivity for VLAN 20.
From PC3, ping PC4 (10.3.3.20). This tests connectivity for VLAN 40. Both pings should be successful, indicating that the EtherChannel is formed, trunking is operational, and the allowed VLANs are correctly propagating.

Additional verification commands:

show etherchannel summary (to verify LACP status and port-channel formation)
show interfaces trunk (to verify trunking mode, native VLAN, and allowed VLANs)

Common mistakes.

common_mistake. 1. Applying trunk configuration to physical interfaces: A frequent mistake is attempting to configure switchport mode trunk or switchport trunk allowed vlan directly on the physical interfaces (e.g., e0/0, e0/1). Once interfaces are bundled into an EtherChannel, their Layer 2 configurations are inherited from the logical Port-channel interface. Configuring them individually often leads to errors or incorrect behavior.

Incorrect LACP modes: Setting both Sw1 and Sw2 to mode active or both to mode passive for channel-group commands will prevent the LACP bundle from forming. The task explicitly states Sw2 'does not negotiate but responds to negotiation requests,' which necessitates mode passive on Sw2 and mode active on Sw1 for successful negotiation.
Missing or incorrect native VLAN: Failing to explicitly configure the native vlan (assuming VLAN 1 for IT_User_VLAN) on the trunk, or mismatching the native VLAN ID between Sw1 and Sw2, will cause communication issues for untagged frames, including control plane traffic.
Incorrect allowed VLANs: Not including the native VLAN (VLAN 1) in the switchport trunk allowed vlan command, or allowing all VLANs (switchport trunk allowed vlan all) instead of explicitly pruning the allowed VLANs to 1, 20, and 40, violates the task requirement.
Forgetting to save configuration: In lab simulations, failing to issue write memory or copy running-config startup-config will result in the loss of all applied configurations upon the device reboot or lab reset, leading to task failure and potential loss of points.

Concept tested. IEEE 802.1Q VLAN Trunking, Cisco EtherChannel configuration, IEEE 802.3ad Link Aggregation Control Protocol (LACP) and its modes (active/passive), Native VLAN configuration, VLAN pruning on trunks, and basic switch interface configuration (accessing console, privileged and global configuration modes, interface range commands, saving configuration to NVRAM).

Topics

#Ethernet Trunks#802.1Q#Native VLAN#Allowed VLANs on Trunk

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