Chapter 7: Adding Fault Tolerance with EtherChannel
In This Chapter
Examining the basic role of EtherChannel
Setting up EtherChannel on a Cisco switch
Viewing and troubleshooting your EtherChannel configuration
EtherChannel allows you to take ports on a switch and combine them to give you a larger data pipe. In this way, you can double, triple, even quadruple, the amount of data you send between two devices. EtherChannel offers great advantages in high-bandwidth situations where you need more throughput.
EtherChannel does not suffer from the delays that Spanning Tree Protocol (STP) does when a failover happens because as long as at least one inter-switch link is still up, there is no interruption (as short as 2 seconds), only reduced bandwidth. (Refer to Book III, Chapter 6, for more on STP.) In situations where absolutely no network interruption can occur, you may prefer EtherChannel to STP. They are not mutually exclusive. You can create two EtherChannel port groups on the same pair of switches, and STP will kick in and do what it is designed to do — prevent this type of loop and block one link while forwarding traffic on the other link.