Configuring Lacp Hot-Standby Ports - Cisco Catalyst 3750 Software Configuration Manual

Chapter 27 Configuring EtherChannels
Command
Step 3 pagp learn-method physical-port
Step 4
pagp port-priority priority
Step 5
end
Step 6 show running-config
or
show pagp channel-group-number internal
Step 7
copy running-config startup-config
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):
•
•
•
•
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.
78-15870-01
LACP system priority
System ID (a combination of the LACP system priority and the switch MAC address)
LACP port priority
Port number
Purpose
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 27-15.
The learning method must be configured the same at both ends
of the link.
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.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 3750 Metro Switch Software Configuration Guide
Configuring EtherChannels
27-17