Chapter 3. EtherChannels
An EtherChannel is a method of combining several physical links between switches into one logical connection. This is typically used when you need increased bandwidth between switches and also provides link redundancy. As illustrated in Figure 3-1, Spanning Tree normally blocks redundant links to avoid loops; EtherChannels circumvent that and enable load balancing across those links. A logical interface called the Port Channel interface is created. Spanning Tree then acts as if the port channel interface were a single physical interface.