EtherChannel Configuration Guidelines If improperly configured, some EtherChannel ports are automatically disabled to avoid network loops and other problems. Follow these guidelines to avoid configuration problems: • A maximum of 128 EtherChannels are supported on a switch or switch stack. • Configure all ports in an EtherChannel to operate at the same speeds and duplex modes. • Enable all ports in an EtherChannel. A port in an EtherChannel that is disabled by using the shutdown interface configuration command is treated as a link failure, and its traffic is transferred to one of the remaining ports in the EtherChannel.
• When a group is first created, all ports follow the parameters set for the first port to be added to the group. If you change the configuration of one of these parameters, you must also make the changes to all ports in the group: • Allowed-VLAN list • Spanning-tree path cost for each VLAN • Spanning-tree port priority for each VLAN • Spanning-tree Port Fast setting • Do not configure a port to be a member of more than one EtherChannel group. • Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running PAgP and LACP can coexist on the same switch or on different switches in the stack.
Individual EtherChannel groups can run either PAgP or LACP, but they cannot interoperate. • Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an IEEE 802.1x port. If you try to enable IEEE 802.1x on an EtherChannel port, an error message appears, and IEEE 802.1x is not enabled. • If EtherChannels are configured on device interfaces, remove the EtherChannel configuration from the interfaces before globally enabling IEEE 802.1x on a device by using the dot1x system-auth-control global configuration command. Layer 2 EtherChannel Configuration Guidelines When configuring Layer 2 EtherChannels, follow these guidelines:
Configuring EtherChannels EtherChannel Configuration Guidelines Feature Default Setting LACP port priority 32768 on all ports. LACP system priority 32768. LACP system ID LACP system priority and the switch or stack MAC address. Load-balancing Load distribution on the switch is based on the source-MAC address of the incoming packet. The source-MAC address is src-mac. Configuring EtherChannels 11