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Difficulty: HardLayer 2 and Layer 3 EtherChannel (LACP)

A network administrator is migrating a pair of trunk links connecting two distribution switches to a routed Layer 3 EtherChannel using IEEE 802.3ad LACP. Interfaces GigabitEthernet1/0/1 and GigabitEthernet1/0/2 need to be bundled into Port-channel 5 with IPv4 address 10.0.5.1/3010.0.5.1/30 assigned to the logical interface. In what operational sequence must these CLI configuration steps be executed on the switch to successfully create this Layer 3 EtherChannel?

  1. 1Select physical member interfaces GigabitEthernet1/0/1 and GigabitEthernet1/0/2 using interface range configuration mode.
  2. 2Disable Layer 2 switchport functionality on the physical member interfaces using the `no switchport` command.
  3. 3Assign physical member interfaces to the EtherChannel bundle using `channel-group 5 mode active`.
  4. 4Enter interface configuration mode for the newly created logical interface using `interface Port-channel 5`.
  5. 5Assign the IPv4 address to the logical bundle using `ip address 10.0.5.1 255.255.255.252`.

Answer

The correct operational sequence begins by selecting physical member interfaces via interface range mode, converting them to Layer 3 routed ports using `no switchport`, binding them to LACP bundle 5 with `channel-group 5 mode active`, entering `interface Port-channel 5` configuration mode, and finally assigning IPv4 address 10.0.5.1/3010.0.5.1/30 directly to the logical port-channel.
To build an operational Layer 3 LACP EtherChannel, physical member links must first be selected and converted into routed interfaces (`no switchport`). Adding these converted interfaces to a channel group with `mode active` automatically creates a Layer 3 logical port-channel and starts LACP negotiation. Finally, configuration transitions to `interface Port-channel 5`, where the IP address is applied to the logical bundle.

Step-by-Step Solution

1
Execute `interface range GigabitEthernet1/0/1 - 2`.
Enters range interface configuration mode for both physical member interfaces.
Configuration commands must be applied simultaneously to member interfaces to maintain identical operational states.
2
Execute `no switchport` on the physical interface range.
Converts physical member interfaces from Layer 2 switchports into Layer 3 routed ports.
Member interfaces must be routed ports prior to group assignment so that Cisco IOS instantiates a Layer 3 Port-channel interface.
3
Execute `channel-group 5 mode active`.
Instantiates Port-channel 5 and enables active IEEE 802.3ad LACP negotiation on the physical interfaces.
Active mode ensures the switch actively sends LACP Link Aggregation Control Protocol Data Units (LACPDUs) to negotiate EtherChannel formation.
4
Execute `interface Port-channel 5`.
Enters interface configuration sub-mode for logical interface Port-channel 5.
Layer 3 protocol configuration and IP routing parameters belong to the logical bundle interface.
5
Execute `ip address 10.0.5.1 255.255.255.252` on the port-channel interface.
Configures the IP address and subnet mask on the logical EtherChannel bundle.
In Layer 3 EtherChannels, packets are routed to the port-channel interface, which then distributes traffic across physical member links using the load-balancing hash.

Key Concept

Layer 3 EtherChannel LACP Configuration Sequence
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Topics

Layer 2 and Layer 3 EtherChannel (LACP)

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