C H A P T E R 38 Configuring Etherchannels And Link-State Tracking; Etherchannel Overview - Cisco WS-CBS3032-DEL Software Configuration Manual

Understanding EtherChannels

EtherChannel Overview

An EtherChannel consists of individual Gigabit Ethernet links bundled into a single logical link as shown
in Figure
Figure 38-1
Gigabit EtherChannel
The EtherChannel provides full-duplex bandwidth up to 8 Gb/s (Gigabit EtherChannel) or 80 Gb/s
(10-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 either Layer 2 or Layer 3 ports. The number of EtherChannels is
limited to 64. 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. Configure both ends of the EtherChannel in the same
mode:
•
•
You can create an EtherChannel on a standalone switch, on a single switch in the stack, or on multiple
switches in the stack (known as cross-stack EtherChannel). See
If a link within an EtherChannel fails, traffic previously carried over that failed link moves to the
remaining links within the EtherChannel. If traps are enabled on the switch, a trap is sent for a failure
that identifies the switch, the EtherChannel, and the failed link. Inbound broadcast and multicast packets
on one link in an EtherChannel are blocked from returning on any other link of the EtherChannel.
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
38-2
38-1.
Typical EtherChannel Configuration
Catalyst 6500
series switch
Blade
Switch
Blade
Blade
Server 1
Server 16
38-11. The EtherChannel Layer 3 ports are made up of routed ports. Routed ports are physical ports
Chapter 11, "Configuring Interface Characteristics."
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. If the
remote port cannot negotiate an EtherChannel, 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.
Chapter 38 Configuring EtherChannels and Link-State Tracking
"EtherChannel Configuration Guidelines" section on
Figure 38-2 and Figure 38-3.
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