LACP is part of the IEEE specification 802.3ad that allows you to bundle several physical ports to form a single logical channel. When you change the number of active bundled ports on a port-channel, traffic patterns will reflect the rebalanced state of the port channel.
Here are the steps needed to configure LACP on a Cisco Switch. For more details on the commands used, see the links below.
Step 1: Enter global configuration mode and specifies the port channel interface. This enters interface configuration mode as shown below
Switch#configure terminal Switch(config)#interface port-channel 5
- No need to configure IP etc.
Step 2: Next bundle it to the interface
switch(config)# interface fastethernet 0/1 and if you have more than one port use port range to bundle this together. i.e, switch(config)# interface range fastethernet 0/1 - 4
Step 3: Assigns the interface to a port channel group and sets the LACP mode.
switch(config-if)# channel-group 5 mode active
Below are the types of LACP modes that can be assigned to a channel group
Active: Places a port into an active negotiating state, in which the port initiates negotiations with other ports by sending LACP packets.
Passive: Places a port into a passive negotiating state, in which the port responds to LACP packets it receives but does not initiate LACP negotiation. In this mode, the channel-group attaches the interface to the bundle.
On: All static EtherChannels, that is, the port is not running LACP messaging but static bundling. With this mode, the switch or the other end switch will not recognize any problem with ether channel and will not tell about the problem.
See the links below for more