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21-2
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-03
Chapter21 Configuring EtherChannel
Understanding EtherChannel
Figure 21-1 Typical EtherChannel Configuration
Understanding Port-Channel Interfaces
You create an EtherChannel for Layer 2 interfaces differently from Layer 3 interfaces. Both
configurations involve logical interfaces.
• With Layer 3 interfaces, you manually create the logical interface by using the interface
port-channel global configuration command.
• With Layer 2 interfaces, the logical interface is dynamically created.
• With both Layer 3 and 2 interfaces, you manually assign an interface to the EtherChannel by using
the channel-group interface configuration command. This command binds the physical and logical
ports together as shown in Figure 21-2.
Each EtherChannel has a logical port-channel interface numbered from 1 to 64. The channel groups are
also numbered from 1 to 64.
Catalyst 8500, 6000,
5500, or 4000
series switch
Catalyst 3550-12T
switch
Gigabit EtherChannel
Catalyst 3550-12T
switch
Workstations
10/100
Switched
links
43267
Catalyst 3550-12T
switch
Workstations
10/100
Switched
links
1000BASE-X 1000BASE-X