EtherChannel is a port trunking (aggregation in Cisco's term) technology primarily used on Cisco switches. It allows grouping several physical Ethernet links to create one logical Ethernet link for the purpose of providing fault-tolerance and high-speed links between switches, routers, and servers.
An EtherChannel can be created from between two and eight Fast Ethernet, Gigabit Ethernet, or 10 Gigabit Ethernet ports. EtherChannel is primarily used in the backbone network, but can also be used to connect UNIX and PC.
EtherChannel provides incremental trunk speeds between Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet. EtherChannel combines multiple Fast Ethernet up to 800Mbps, Gigabit Ethernet up to 8Gbps , and 10 Gigabit Ethernet up to 80Gbps.