28-17
Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 28 Configuring EtherChannels
Configuring EtherChannels
To return the priority to its default setting, use the no pagp port-priority interface configuration
command. To return the learning method to its default setting, use the no pagp learn-method interface
configuration command.
Configuring LACP Hot-Standby Ports
When enabled, LACP tries to configure the maximum number of LACP-compatible ports in a channel,
up to a maximum of 16 ports. Only eight LACP links can be active at one time. The software places any
additional links in a hot-standby mode. If one of the active links becomes inactive, a link that is in the
hot-standby mode becomes active in its place.
If you configure more than eight links for an EtherChannel group, the software automatically decides
which of the hot-standby ports to make active based on the LACP priority. The software assigns to every
link between systems that operate LACP a unique priority made up of these elements (in priority order):
•
LACP system priority
•
System ID (a combination of the LACP system priority and the switch MAC address)
•
LACP port priority
•
Port number
In priority comparisons, numerically lower values have higher priority. The priority decides which ports
should be put in standby mode when there is a hardware limitation that prevents all compatible ports
from aggregating.
Step 3
pagp learn-method physical-port
Select the PAgP learning method.
By default, aggregation-port learning is selected, which means
the switch sends packets to the source by using any of the ports
in the EtherChannel. With aggregate-port learning, it is not
important on which physical port the packet arrives.
Select physical-port to connect with another switch that is a
physical learner. Make sure to configure the port-channel
load-balance global configuration command to src-mac as
described in the
“Configuring EtherChannel Load Balancing”
section on page 28-15
.
The learning method must be configured the same at both ends
of the link.
Step 4
pagp port-priority priority
Assign a priority so that the selected port is chosen for packet
transmission.
For priority, the range is 0 to 255. The default is 128. The higher
the priority, the more likely that the port will be used for PAgP
transmission.
Step 5
end
Return to privileged EXEC mode.
Step 6
show running-config
or
show pagp channel-group-number internal
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
