EtherChannel combines multiple switch ports into a single, logical link between two switches. With EtherChannel:
- You can combine 2-8 ports into a single link.
- All links in the channel group are used for communication between the switches.
- Use EtherChannel to increase the bandwidth between switches.
- Use EtherChannel to establish automatic-redundant paths between switches. If one link fails, communication will still occur over the other links in the group.
- Use EtherChannel to reduce spanning tree convergence times.
Use the channel-group command for a port to enable EtherChannel as follows:
Switch(config)#interface fast 0/12
Switch(config-if)#channel-group 1 mode on
Each channel group has its own number. All ports assigned to the same channel group will be viewed as a single logical link.
Note: If you do not use the channel-group command, the spanning tree algorithm will identify each link as a redundant path to the other bridge and will put one of the ports in blocking state.