Specifications

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Catalyst 2970 Switch Software Configuration Guide
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Chapter 28 Configuring EtherChannels
Configuring EtherChannels
Default EtherChannel Configuration
Table 28-3 shows the default EtherChannel configuration.
EtherChannel Configuration Guidelines
If improperly configured, some EtherChannel interfaces are automatically disabled to avoid network
loops and other problems. Follow these guidelines to avoid configuration problems:
• More than 12 EtherChannels cannot be configured on a Catalyst 2970 switch.
• Configure a PAgP EtherChannel with up to eight Ethernet interfaces of the same type.
• Configure a LACP EtherChannel with up to 16 Ethernet interfaces of the same type. Up to eight
ports can be active, and up to eight ports can be in standby mode.
• Configure all interfaces in an EtherChannel to operate at the same speeds and duplex modes.
• Enable all interfaces in an EtherChannel. An interface 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 interfaces 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.
Table 28-3 Default EtherChannel Configuration
Feature Default Setting
Channel groups None assigned.
Port-channel logical interface None defined.
PAgP mode No default.
PAgP learn method Aggregate-port learning on all interfaces.
PAgP priority 128 on all interfaces.
LACP mode No default.
LACP learn method Aggregate-port learning on all interfaces.
LACP port priority 32768 on all interfaces.
LACP system priority 32768.
LACP system ID LACP system priority and the switch MAC address.
Load balancing Load distribution on the switch is based on the
source-MAC address of the incoming packet.