Cisco 3032 - Configuring Etherchannels

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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 37 Configuring EtherChannels and Link-State Tracking
Configuring EtherChannels
With PAgP, if the stack master fails or leaves the stack, a new stack master is elected. A spanning-tree
reconvergence is not triggered unless there is a change in the EtherChannel bandwidth. The new stack
master synchronizes the configuration of the stack members to that of the stack master. The PAgP
configuration is not affected after a stack master change unless the EtherChannel has ports residing on
the old stack master.
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.