What is EtherChannel

EtherChannel has been a part of the Cisco IOS for many years, so you should find that all your switches support it with proper configuration. Do not be afraid to enable it on a pair of ports and try it.
When setting up an EtherChannel connection, remember the following points; they can help you avoid problems during the configuration process:

• You can configure up to eight ports, and all of these ports should be the same type (Fast Ethernet, Gigabit Ethernet).
• Set all ports to function at the same Speed and Duplex settings.
• Ensure that all ports are enabled and that none have been configured using the shutdown command.
• Switchport settings from the first port in EtherChannel are copied to all other ports in the EtherChannel when the ports are added to the channel group. This is a copy action and not a link, so if you change the settings after the fact, you need to change the settings on all ports. The settings that must remain the same across all ports are

EtherChannel Modes

Mode	Protocol	Description
Auto	PAgP	Sets the interface to respond to PAgP negotiation packets, but the interface will start negotiations on its own.
Desirable	PAgP	Sets the interface to actively attempt to negotiate a PAgP connection.
On	EtherChannel	Forces the connection to bring all links up without using a protocol to negotiate connections. This mode can only connect to another device that is also set to on. When using this mode, the switch does not negotiate the link using either PAgP or LACP.
Active	LACP	Sets the interface to actively attempt to negotiate connections with other LACP devices.
Passive	LACP	Sets the interface to respond to LACP data if it receives negotiation requests from other systems.