Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
OL-8566-02
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
pagp learn-method
pagp learn-method
Use the pagp learn-method interface configuration command to learn the source address of incoming
packets received from an EtherChannel port. Use the no form of this command to return to the default
setting.
pagp learn-method {aggregation-port | physical-port}
no pagp learn-method
Syntax Description
Defaults The default is aggregation-port (logical port channel).
Command Modes Interface configuration
Command History
Usage Guidelines The learn method must be configured the same at both ends of the link.
Note The switch supports address learning only on aggregate ports even though the physical-port keyword
is provided in the CLI. The pagp learn-method and the pagp port-priority interface configuration
commands have no effect on the switch hardware, but they are required for PAgP interoperability with
devices that only support address learning by physical ports, such as the Catalyst 1900 switch.
When the link partner to the Catalyst 3550 switch is a physical learner, we recommend that you
configure the switch as a physical-port learner by using the pagp learn-method physical-port interface
configuration command and to set the load-distribution method based on the source MAC address by
using the port-channel load-balance src-mac global configuration command. Use the pagp
learn-method interface configuration command only in this situation.
aggregation-port Specify address learning on the logical port-channel. The switch sends
packets to the source by using any of the interfaces in the EtherChannel. This
setting is the default. With aggregate-port learning, it is not important on
which physical port the packet arrives.
physical-port Specify address learning on the physical port within the EtherChannel. The
switch sends packets to the source by using the same interface in the
EtherChannel from which it learned the source address. The other end of the
channel uses the same port in the channel for a particular destination MAC or
IP address.
Release Modification
12.1(4)EA1 This command was introduced.