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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter21 Configuring EtherChannel
Configuring EtherChannel
Configuring the Physical Interfaces
Beginning in privileged EXEC mode, follow these steps to assign an Ethernet interface to a Layer3
EtherChannel:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and specify a physical
interface to configure.
Valid interfaces include physical interfaces.
Up to eight interfaces of the same type and speed can be
configured for the same group.
Step3 no ip address Ensure that there is no IP address assigned to the physica l
interface.
Step4 channel-group channel-group-number mode
{auto [non-silent] | desirable [non-silent] | on}Assign the interface to a channel group, and specify the PAgP
mode (the default mode is auto silent).
For channel-group-number, the range is 1 to 64. This number
must be the same as the port-channel-number (logical port)
configured in the “Creating Port-Channel Logical Interfaces”
section on page 21-11.
Each EtherChannel can consist of up to eight compa ti bly
configured Ethernet interfaces.
For mode, select one of these keywords:
•auto—Enables PAgP only if a PAgP device is detected. It
places an interface into a passive negotiating state, in which
the interface responds to PAgP packets it receives but does
not start PAgP packet negotiation.
•desirable—Unconditionally enables PAgP. It places an
interface into an active negotiating state, in which the
interface starts negotiations with other interfaces by sending
PAgP packets.
•on—Forces the interface to channel without PAgP. With the
on mode, a usable EtherChannel exists only when an
interface group in the on mode is connected to another
interface group in the on mode.
•non-silent—If your switch is connected to a partner that is
PAgP capable, you can configure the switch interface for
nonsilent operation. You can configure an interface with the
non-silent keyword for use with the auto or desirable mode.
If you do not specify non-silent with the auto or desirable
mode, silent is assumed. The silent setting is for connections
to file servers or packet analyzers; this setting allows PAgP
to operate, to attach the interface to a channel group, and to
use the interface for transmission.
For information on compatible PAgP modes for the switch and its
partner, see the “PAgP M ode s” section on page 21-4.