EtherChannel Configuration Lab

Imagine a company that wants to double its bandwidth and ensure redundancy between switches but without causing loops. That’s exactly what EtherChannel does: it combines multiple physical links into a single logical one.

So far in this course, we’ve seen how EtherChannel can be configured using different methods:

• Static EtherChannel

• LACP (Link Aggregation Control Protocol)

• PAgP (Port Aggregation Protocol)

• Layer 3 EtherChannel

In this lab, you’ll put all of that into practice.
We’ll recap everything step by step, so you can configure and verify each EtherChannel type directly in Packet Tracer.

How to Begin

Before starting, download the lab file using the button at the top of the page.
You’ll find a ready-made topology with all IP addresses and VLANs pre-configured, so you can focus entirely on the EtherChannel setup.

Figure 1 - EtherChannel Configuration Topology

The goal of this lab is simple: you’ll configure EtherChannel between switches using different methods, then verify that the PC can successfully ping the Server through the aggregated links.

Lab Overview

Here’s the structure we’ll follow throughout this lab:

• Step 1 – Configure a Layer 2 EtherChannel between SW1 and DSW1 using PAgP and set the interfaces as trunk ports.
  

• Step 2 – Configure a Layer 2 EtherChannel between SW2 and DSW2 using LACP and set the interfaces as trunk ports.
  

• Step 3 – Configure a static Layer 3 EtherChannel between DSW1 and DSW2 and assign IP addresses.
  

• Step 4 – Configure static routing on DSW1 and DSW2 to allow communication between the PC and the server.
  

• Step 5 – Verify connectivity by pinging the server from the PC.

Let’s Get Started

Open the Packet Tracer file and try to configure the first EtherChannel on your own.
This way, you’ll actively apply what you’ve learned before checking the guided solution that follows.

In the next sections, we’ll walk through each configuration step together, explain the commands, and verify that everything works correctly.

In this first step, we’ll configure an EtherChannel between SW1 and DSW1 using the PAgP protocol.
This will allow both switches to dynamically negotiate the bundle and act as a single logical trunk.

Figure 2 - PAgP EtherChannel Configuration Topology

Configuring SW1

Let’s start by connecting to SW1 and grouping interfaces GigabitEthernet 0/1 and 0/2 into a single EtherChannel.

SW1# configure terminal
SW1(config)# interface range gigabitEthernet 0/1-2
SW1(config-if-range)# channel-group 1 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected

Among the available modes, desirable and auto belong to PAgP.
We’ll choose desirable so the switch actively forms the EtherChannel.

SW1(config-if-range)# channel-group 1 mode desirable
Creating a port-channel interface Port-channel 1

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to up

At this stage, the logical interface Port-channel 1 has been created, and both links are now bundled.
However, the EtherChannel is still inactive since the opposite switch is not yet configured.

Let’s now enable trunking on this new Port-Channel.

Set Port-Channel as Trunk

To enable trunking, we apply the switchport mode trunk command under the Port-Channel interface.

SW1(config)# interface po1
SW1(config-if)# switchport mode trunk

That’s it. The logical interface is now acting as a trunk.
Let’s check the EtherChannel status to confirm the configuration.

Check EtherChannel Status

The show etherchannel summary command displays all EtherChannels configured on the device.
Here, Po1 is flagged as SD, which means the EtherChannel is Layer 2 (S) but currently Down (D).

SW1# show etherchannel summary 
Flags:  D - down        P - in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      f - failed to allocate aggregator
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port

Number of channel-groups in use: 1
Number of aggregators:           1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+----------------------------------------------
1      Po1(SD)           PAgP   Gig0/1(I) Gig0/2(I) 

This is perfectly normal for now, the opposite switch hasn’t been configured yet.

Configuring DSW1

Now, let’s move to DSW1 and configure the same EtherChannel.
We’ll bundle GigabitEthernet 1/0/1 and 1/0/2 into Port-Channel 1 using desirable mode.
We could have used auto, but using desirable on both sides ensures negotiation succeeds immediately.

DSW1# configure terminal
DSW1(config)# interface range g1/0/1-2
DSW1(config-if-range)# channel-group 1 mode desirable
Creating a port-channel interface Port-channel 1

The logical interface Po1 has now been created.
Next, let’s enable trunking on it.

Set Port-Channel as Trunk

We’ll apply the same principle: enable trunking directly under the Port-Channel interface.

DSW1(config)# interface po1
DSW1(config-if)# switchport mode trunk

Let’s now verify if the EtherChannel is up and operational.

Check EtherChannel Status

The show etherchannel summary output now shows SU, indicating that the EtherChannel is Layer 2 (S) and Up (U) which means it’s working properly.

DSW1# show etherchannel summary 
Flags:  D - down        P - in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      f - failed to allocate aggregator
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port

Number of channel-groups in use: 1
Number of aggregators:           1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+----------------------------------------------
1      Po1(SU)           PAgP   Gig1/0/1(P) Gig1/0/2(P)

Each physical interface now shows (P), confirming it’s actively participating in the bundle.

Verify Trunk Configuration

We can also confirm that the trunk is correctly operational using the show interfaces trunk command.

DSW1# show interfaces trunk 
Port        Mode         Encapsulation  Status        Native vlan
Po1         on           802.1q         trunking      1

Port        Vlans allowed on trunk
Po1         1-1005

Port        Vlans allowed and active in management domain
Po1         1

Port        Vlans in spanning tree forwarding state and not pruned
Po1         none

Perfect, the EtherChannel is now up, trunking, and fully operational.
You’ve successfully configured a Layer 2 EtherChannel using PAgP.

In this step, you will configure an EtherChannel between SW2 and DSW2 using LACP.
Unlike PAgP, LACP follows the IEEE 802.3ad standard, which means it can work across devices from different vendors.

Figure 3 - LACP EtherChannel Configuration Topology

Configuring SW2

Let’s start by connecting to SW2.
You will group GigabitEthernet 0/1 and 0/2 into a single logical interface called Port-Channel 2.