The next topic in our serie is EtherChannel. CCIE+Enterprise+Infrastructure+(v1.0+RevA)+Exam+Topics.pdf (cisco.com)

What is an EtherChannel?

Is a technique to bundle physical interfaces (Called members) into a logical one (Called Port-Channel) in order to increase the bandwidth and provide a certain redundancy in case a link fails. It also prevent the network to unused certain links to be blocked by Spanning-Tree Protocol, by acting as a single logical link.

Remark: EtherChannel offers more bandwidth, but not more throughput. The flows are always attached to one physical link, therefore the throughput of the phyisical links are the limitations for a flow.

Multi Chassis Etherchannel