C H A P T E R 28 Configuring Etherchannels - Cisco 3845 - Security Bundle Router Software Manual

Understanding EtherChannels
Figure 28-1
The EtherChannel provides full-duplex bandwidth of up to 800 Mbps between your switch and another
switch or host for Fast EtherChannel on a switch with 24 Fast Ethernet ports. For Gigabit EtherChannel,
you can configure up to 8 Gbps (8 ports of 1 Gbps), depending on the number of supported Gigabit
Ethernet interfaces.
Each EtherChannel can consist of up to eight compatibly configured Ethernet ports. All ports in each
EtherChannel must be configured as either Layer 2 or Layer 3 ports. The number of EtherChannels is
limited to 48. For more information, see the
page
configured to be in Layer 3 mode by using the no switchport interface configuration command. For
more information, see the
You can configure an EtherChannel in one of these modes: Port Aggregation Protocol (PAgP), Link
Aggregation Control Protocol (LACP), or On mode. 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.
• 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.
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.
Cisco ME 3800X and 3600X Switch Software Configuration Guide
28-2
Typical EtherChannel Configuration
Catalyst 8500
series switch
Gigabit EtherChannel
1000BASE-X
10/100
Switched
links
Workstations
28-9. The EtherChannel Layer 3 ports are made up of routed ports. Routed ports are physical ports
Chapter 9, "Configuring Interfaces."
1000BASE-X
10/100
Switched
links
Workstations
"EtherChannel Configuration Guidelines" section on
Chapter 28 Configuring EtherChannels
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