37-2
Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter37 Configuring EtherChannels and Link-State Tracking
Understanding EtherChannels
EtherChannel Overview
An EtherChannel consists of individual Gigabit Ethernet links bundled into a single logica l link as shown
in Figure37-1.
Figure37-1 Typical EtherChannel Configuration
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 E ther ne t po rts. Al l po rts i n eac h
EtherChannel must be configured as either Layer 2 or Laye r 3 ports. The number of EtherChannels is
limited to 48. For more information, see the “EtherChannel Configuration Guidelines” section on
page 37-11. The EtherChannel Layer 3 ports are made up of routed ports. Routed port s are physical ports
configured to be in Layer 3 mode by using the no switchport interface configuration command. For
more information, see the Chapter10, “Configuring Interface Characteristics.”
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 EtherCh an nel in the sa me
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. 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 co nfigurat ion do es 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 EtherCha nnel. The oth er end of the channel (on the other
switch) must also be configured in the on mode; otherwise, packet loss can occur.
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 Figure 37-2 and Figure 37-3.
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 a ny othe r lin k of th e Eth erC hanne l.
Catalyst 6500
series switch
G
igabit EtherChannel
Blade
Switch
Blade
Server 1 Blade
Server 16
119704