Cisco Catalyst 3030 Command Reference Manual page 57

Chapter 2 Cisco Catalyst Blade Switch 3030 Cisco IOS Commands
Defaults No channel groups are assigned.
No mode is configured.
Command Modes Interface configuration
Command History Release
12.2(25)SEE
Usage Guidelines For Layer 2 EtherChannels, you do not have to create a port-channel interface first by using the interface
port-channel global configuration command before assigning a physical port to a channel group.
Instead, you can use the channel-group interface configuration command. It automatically creates the
port-channel interface when the channel group gets its first physical port if the logical interface is not
already created. If you create the port-channel interface first, the channel-group-number can be the same
as the port-channel-number, or you can use a new number. If you use a new number, the channel-group
command dynamically creates a new port channel.
After you configure an EtherChannel, configuration changes that you make on the port-channel interface
apply to all the physical ports assigned to the port-channel interface. Configuration changes applied to
the physical port affect only the port where you apply the configuration. To change the parameters of all
ports in an EtherChannel, apply configuration commands to the port-channel interface, for example,
spanning-tree commands or commands to configure a Layer 2 EtherChannel as a trunk.
If you do not specify non-silent with the auto or desirable mode, silent is assumed. The silent mode is
used when the switch is connected to a device that is not PAgP-capable and seldom, if ever, sends
packets. A example of a silent partner is a file server or a packet analyzer that is not generating traffic.
In this case, running PAgP on a physical port prevents that port from ever becoming operational.
However, it allows PAgP to operate, to attach the port to a channel group, and to use the port for
transmission. Both ends of the link cannot be set to silent.
In the on mode, an EtherChannel exists only when a port group in the on mode is connected to another
port group in the on mode.
You should use care when using the on mode. This is a manual configuration, and ports on both ends of
Caution
the EtherChannel must have the same configuration. If the group is misconfigured, packet loss or
spanning-tree loops can occur.
Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running
PAgP and LACP can coexist on the same switch. Individual EtherChannel groups can run either PAgP
or LACP, but they cannot interoperate.
If you set the protocol by using the channel-protocol interface configuration command, the setting is
not overridden by the channel-group interface configuration command.
Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an
IEEE 802.1x port. If you try to enable IEEE 802.1x authentication on an EtherChannel port, an error
message appears, and IEEE 802.1x authentication is not enabled.
Do not configure a secure port as part of an EtherChannel or an EtherChannel port as a secure port.
78-17262-01
Modification
This command was introduced.
Cisco Catalyst Blade Switch 3030 Command Reference
channel-group
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