In this short article we will configure some Layer 2 EtherChannel links. These are used to aggregate switchports to increase bandwidth and provide redundancy. I am running a four port EtherChannel from my Edge router to my Core switch. This article is useful for CCNP (BCMSN) studies.

First we will configure our switchports, then we will configure the Port-Channel interface, then we’ll look at some show commands.

Here is the switchport configuration:

interface range GigabitEthernet0/23 - 26
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 10
 switchport mode trunk
 channel-group 1 mode on

We’ve set the trunking encapsulation to 802.1q and turn trunking on, then we set the native VLAN (I use 10), the command to note is “channel-group”, we have made the group 1 and set the mode to “on”, this means the port will not negotiate to become an EtherChannel, it just is.

Next we configure the Port-Channel interface:

interface Port-channel1
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 10
 switchport mode trunk

This is just a logical interface (somewhat similar to a Loopback). We do the same trunk configuration here.