The following guidelines and restrictions are useful for configuring EtherChannel:
- EtherChannel support - All Ethernet interfaces on all modules must support EtherChannel with no requirement that interfaces be physically contiguous, or on the same module.
- Speed and duplex - Configure all interfaces in an EtherChannel to operate at the same speed and in the same duplex mode, as shown in the figure.
- VLAN match - All interfaces in the EtherChannel bundle must be assigned to the same VLAN, or be configured as a trunk (also shown in the figure).
- Range of VLAN - An EtherChannel supports the same allowed range of VLANs on all the interfaces in a trunking EtherChannel. If the allowed range of VLANs is not the same, the interfaces do not form an EtherChannel, even when set to auto or desirable mode.
If these settings must be changed, configure them in port channel interface configuration mode. After the port channel interface is configured, any configuration that is applied to the port channel interface also affects individual interfaces. However, configurations that are applied to the individual interfaces do not affect the port channel interface. Therefore, making configuration changes to an interface that is part of an EtherChannel link may cause interface compatibility issues.