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Catalyst 2960 Switch Software Configuration Guide
OL-8603-04
Chapter 31 Configuring EtherChannels and Link-State Tracking
Understanding EtherChannels
EtherChannel Overview
An EtherChannel consists of individual Fast Ethernet or Gigabit Ethernet links bundled into a single
logical link as shown in Figure 31-1.
Figure 31-1 Typical EtherChannel Configuration
The EtherChannel provides full-duplex bandwidth up to 800 Mb/s (Fast EtherChannel) or 8 Gb/s
(Gigabit EtherChannel) between your switch and another switch or host.
Each EtherChannel can consist of up to eight compatibly configured Ethernet ports. All ports in each
EtherChannel must be configured as Layer 2 ports. The number of EtherChannels is limited to six. For
more information, see the “EtherChannel Configuration Guidelines” section on page 31-9.
You can configure an EtherChannel in one of these modes: Port Aggregation Protocol (PAgP), Link
Aggregation Control Protocol (LACP), or On. Configure both ends of the EtherChannel in the same
mode:
• When you configure one end of an EtherChannel in either PAgP or LACP mode, the system
negotiates with the other end of the channel to determine which ports should become active.
Incompatible ports are suspended. Beginning with Cisco IOS Release 12.2(35)SE, instead of a
suspended state, the local port is put into an independent state and continues to carry data traffic as
would any other single link. The port configuration does not change, but the port does not participate
in the EtherChannel.
• When you configure an EtherChannel in the on mode, no negotiations take place. The switch forces
all compatible ports to become active in the EtherChannel. The other end of the channel (on the other
switch) must also be configured in the on mode; otherwise, packet loss can occur.
101237
Catalyst 8500
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Gigabit EtherChannel
Workstations
10/100
Switched
links
Workstations
10/100
Switched
links
1000BASE-X 1000BASE-X
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