Achieving Awesome Single-Stream Performance Over Bonded Ethernet
Ethernet Link Aggregation (aka PortChannel, Etherchannel, ethernet bonding, NIC teaming, trunking, link bundling, Smartgroup, Ethertrunk, etc) is a way to combine multiple Ethernet links to a single logical link. This improves redundancy and increases aggregate performance. It is good stuff, especially if you are into High Availability.
Here is a typical setup:
A good start. If you can spare the ports and cables to make this work, you should do it.