Etherchannel Overview - Cisco IE 3000 Software Configuration Manual

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 33-1
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
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:
•
•
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 IE 3000 Switch Software Configuration Guide
33-2
Figure
Typical EtherChannel Configuration
Catalyst 8500
series switch
Gigabit EtherChannel
1000BASE-X
10/100
Switched
links
Workstations
"EtherChannel Configuration Guidelines" section on page
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. 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.
Chapter 33
33-1.
1000BASE-X
10/100
Switched
links
Workstations
Configuring EtherChannels and Link-State Tracking
33-9.
OL-13018-01