EtherChannel

EtherChannel Configuration

Switch#config t
Switch(config)#int fa 0/11
Switch(config-if)#channel-group x mode on	x is the number of the channel-group and must match the other interface
Switch(config-if)#int fa 0/12
Switch(config-if)#channel-group x mode on	x is the number of the channel-group and must match the other interface

Verification of EtherChannel

Switch#show etherchannel x detail	Displays detailed information
Switch#show etherchannel x port	Displays EtherChannel port information
Switch#show etherchannel x port-channel	Displays port-channel information
Switch#show etherchannel x summary	Displays a one-line summary per channel-group

EtherChannel Tips

• Can combine from two to eight parallel Ethernet links

• 1900 Switches need 8.00.03 or later Enterprise Edition software

• 2900 Switches need IOS 11.2(8)SA or later

• 2950 Switches need IOS 12.0(5.2)WC(1) or later

• There are three different modes for EtherChannelauto, desirable, and on:

  - auto tells switch to wait for other switch to start EtherChannel negotiations. If auto is set on both sides, EtherChannel will never formboth sides are waiting for the other side to start negotiating!

  - desirable tells switch it is willing to turn EtherChannel on.

  - on tells switch it wants to form an EtherChannel.

  Only the combinations of auto-desirable, desirable-desirable, and on-on will allow a channel to be formed.

  If a device on one side of the channel does not support PAgP, such as a router, the device on the other side must have PAgP set to on.

• All ports must be identical

  - Same Speed and Duplex

• Cannot mix Fast Ethernet and Gigabit Ethernet

• Must all be VLAN trunk or non-trunk operational status