37-4
Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 37 Configuring EtherChannels and Link-State Tracking
Understanding EtherChannels
Figure 37-3
Cross-Stack EtherChannel
Port-Channel Interfaces
When you create a Layer 2 EtherChannel, a port-channel logical interface is involved. You can create
the EtherChannel in these ways:
•
Use the
channel-group
interface configuration command. This command automatically creates the
port-channel logical interface when the channel group gets its first physical port. The
channel-group
command binds the physical (10/100/1000 ports) and the logical ports together as
shown in
•
Use the
interface port-channel
port-channel-number
global configuration command to manually
create the port-channel logical interface. Then use the
channel-group
channel-group-number
interface configuration command to bind the logical interface to a physical port. 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.
Each EtherChannel has a port-channel logical interface numbered from 1 to 6. This port-channel
interface number corresponds to the one specified with the
channel-group
interface configuration
command.
Switch 1
Catalyst 2975 switch stack
Switch 2
Channel
group 1
Stack port
connections
Switch 3
Switch A
250884