How to Configure EtherChannel Link Aggregation Control Protocol (LACP) in Cisco Switch

EtherChannel is a port link aggregation technology developed by Cisco, which provides fault-tolerant high-speed links between Switches, Routers, and Servers.

EtherChannel technology allows multiple physical Ethernet links (Fast EtherNet or Gigabit Ethernet) to combine into one logical channel.

There are two protocols used for negotiating EtherChannel and Link Aggregation. We can configure EtherChannel in three ways in Cisco Switches.

1. Port Aggregation Protocol (PAgP) - Cisco Proprietary protocol
2. IEEE Link Aggregation Control Protocol (LACP) - Industry Standard
3. Manual Etherchannel Configuration - Without using any negotiation protocol listed above

Link Aggregation Control Protocol (LACP) is an industry standard defined in IEEE 802.3AD. Using Link Aggregation Control Protocol (LACP), Cisco switches can negotiate Link Aggregation with switches from different vendors that support 802.3AD protocol.

Follow these steps to configure EtherChannel using Link Aggregation Control Protocol (LACP) in Cisco Switches. The ports which are going to be in EtherChannel must be in the shutdown state while configuring the EtherChannel to prevent loops and other related problems.

Switch omnisecu.com.SW1

omnisecu.com.SW1>
omnisecu.com.SW1>enable
omnisecu.com.SW1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
omnisecu.com.SW1(config)#interface range gigabitEthernet 0/1 - 2
omnisecu.com.SW1(config-if-range)#channel-group 1 mode active 
omnisecu.com.SW1(config-if-range)#channel-protocol lacp 
omnisecu.com.SW1(config-if-range)#exit
omnisecu.com.SW1(config)#exit
omnisecu.com.SW1#

Switch omnisecu.com.SW2

omnisecu.com.SW2>enable 
omnisecu.com.SW2#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
omnisecu.com.SW2(config)#interface range gigabitEthernet 0/1 - 2
omnisecu.com.SW2(config-if-range)#channel-group 1 mode active 
omnisecu.com.SW2(config-if-range)#channel-protocol lacp
omnisecu.com.SW2(config-if-range)#exit
omnisecu.com.SW2(config)#exit
omnisecu.com.SW2#
  

    
omnisecu.com.SW1#show ip interface brief 
Interface              IP-Address      OK? Method Status                Protocol
<output_omitted>
GigabitEthernet0/1     unassigned      YES unset  up                    up
GigabitEthernet0/2     unassigned      YES unset  up                    up
Vlan1                  unassigned      YES unset  administratively down down
Port-channel 1         unassigned      YES unset  up                    up
<output_omitted>