Trunk + LACP checklist
Sw1 — Task 1 (physical trunks)
On Sw1, enter configuration mode, create VLANs 15 and 45, then set
GigabitEthernet0/1 and GigabitEthernet0/2 to 802.1Q trunks: native VLAN 45, allowed VLANs
15 and 45. Use exit after each interface to return to global configuration.
Sw1# configure terminal
Sw1(config)# vlan 15
Sw1(config)# vlan 45
Sw1(config)# interface GigabitEthernet0/1
Sw1(config-if)# switchport trunk encapsulation dot1q
Sw1(config-if)# switchport mode trunk
Sw1(config-if)# switchport trunk native vlan 45
Sw1(config-if)# switchport trunk allowed vlan 15,45
Sw1(config-if)# exit
Sw1(config)# interface GigabitEthernet0/2
Sw1(config-if)# switchport trunk encapsulation dot1q
Sw1(config-if)# switchport mode trunk
Sw1(config-if)# switchport trunk native vlan 45
Sw1(config-if)# switchport trunk allowed vlan 15,45
Sw1(config-if)# exit
Sw2 — Task 1 (physical trunks)
Apply the same Task 1 trunk layout on Sw2 so both switches expose VLANs 15 and 45 on
GigabitEthernet0/1 and GigabitEthernet0/2 before you build the EtherChannel in Task 2.
Sw2# configure terminal
Sw2(config)# vlan 15
Sw2(config)# vlan 45
Sw2(config)# interface GigabitEthernet0/1
Sw2(config-if)# switchport trunk encapsulation dot1q
Sw2(config-if)# switchport mode trunk
Sw2(config-if)# switchport trunk native vlan 45
Sw2(config-if)# switchport trunk allowed vlan 15,45
Sw2(config-if)# exit
Sw2(config)# interface GigabitEthernet0/2
Sw2(config-if)# switchport trunk encapsulation dot1q
Sw2(config-if)# switchport mode trunk
Sw2(config-if)# switchport trunk native vlan 45
Sw2(config-if)# switchport trunk allowed vlan 15,45
Sw2(config-if)# exit
Sw1 — Task 2 (LACP + Port-channel15 trunk)
Still in global configuration on Sw1 (after Task 1), bundle GigabitEthernet0/1 and
GigabitEthernet0/2 into port-channel 15 using LACP (mode active), then
apply the same trunk parameters on Port-channel15 as on the physical trunks. Use end to return to
privileged EXEC.
Sw1(config)# interface range GigabitEthernet0/1 - 2
Sw1(config-if-range)# channel-protocol lacp
Sw1(config-if-range)# channel-group 15 mode active
Sw1(config-if-range)# exit
Sw1(config)# interface Port-channel15
Sw1(config-if)# switchport trunk encapsulation dot1q
Sw1(config-if)# switchport mode trunk
Sw1(config-if)# switchport trunk native vlan 45
Sw1(config-if)# switchport trunk allowed vlan 15,45
Sw1(config-if)# end
Sw2 — Task 2 (LACP + Port-channel15 trunk)
Repeat the same Task 2 sequence on Sw2: LACP bundle on the two GigabitEthernet links, then
trunk configuration on Port-channel15, and end to exit configuration mode.
Sw2(config)# interface range GigabitEthernet0/1 - 2
Sw2(config-if-range)# channel-protocol lacp
Sw2(config-if-range)# channel-group 15 mode active
Sw2(config-if-range)# exit
Sw2(config)# interface Port-channel15
Sw2(config-if)# switchport trunk encapsulation dot1q
Sw2(config-if)# switchport mode trunk
Sw2(config-if)# switchport trunk native vlan 45
Sw2(config-if)# switchport trunk allowed vlan 15,45
Sw2(config-if)# end
Verification — PC1 (after Task 1 on both switches)
With Task 1 complete on both switches, open the PC1 command prompt and confirm Layer 3 reachability to
PC2 (10.15.15.20). The simulation only allows successful replies once both sides have the trunk STEPS in place.
PC1> ping 10.15.15.20
Optional — switch EXEC
From privileged EXEC you may inspect trunk status after Task 1 on a switch, and EtherChannel status after the full STEPS
sequence on both switches. Example commands on Sw1 (run similar checks on Sw2 if you like):
Sw1# show interfaces trunk
Sw1# show etherchannel summary
Save — privileged EXEC on each switch
When the lab sequence is complete and PC1 reachability is verified, save the running configuration to startup on
Sw1 and Sw2 from enable mode (copy run start normalizes to the same command).
Sw1# copy running-configuration startup-configuration
Sw2# copy running-configuration startup-configuration