37-10
Cisco Catalyst Switch Module 3110 and 3012 for IBM BladeCenter Software Configuration Guide
OL-12189-01
Chapter 37 Configuring EtherChannels and Link-State Tracking
Configuring EtherChannels
With LACP, the system-id uses the stack MAC address from the stack master, and if the stack master
changes, the LACP system-id can change. If the LACP system-id changes, the entire EtherChannel will
flap, and there will be an STP reconvergence. Use the stack-mac persistent timer command to control
whether or not the stack MAC address changes during a master failover.
For more information about switch stacks, see Chapter 5, “Managing Switch Stacks.”
Configuring EtherChannels
These sections contain this configuration information:
• Default EtherChannel Configuration, page 37-10
• EtherChannel Configuration Guidelines, page 37-11
• Configuring Layer 2 EtherChannels, page 37-12 (required)
• Configuring Layer 3 EtherChannels, page 37-14 (required)
• Configuring EtherChannel Load-Balancing, page 37-17 (optional)
• Configuring the PAgP Learn Method and Priority, page 37-18 (optional)
• Configuring LACP Hot-Standby Ports, page 37-19 (optional)
Note Make sure that the ports are correctly configured. For more information, see the “EtherChannel
Configuration Guidelines” section on page 37-11.
Note After you configure an EtherChannel, configuration changes applied to the port-channel interface apply
to all the physical ports assigned to the port-channel interface, and configuration changes applied to the
physical port affect only the port where you apply the configuration.
Default EtherChannel Configuration
Table 37-3 shows the default EtherChannel configuration.
Table 37-3 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 ports.
PAgP priority 128 on all ports.
LACP mode No default.
LACP learn method Aggregate-port learning on all ports.
LACP port priority 32768 on all ports.
LACP system priority 32768.
