Cisco WS-C2960-24TC-S Software Guide - Page 610

Configuring LACP Hot-Standby Ports, aggregation-port learning

Page 610 highlights

Configuring EtherChannels Chapter 31 Configuring EtherChannels and Link-State Tracking Command Step 3 pagp learn-method physical-port Step 4 pagp port-priority priority Step 5 Step 6 Step 7 end show running-config or show pagp channel-group-number internal copy running-config startup-config 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 31-12. 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. 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. To every link between systems that operate LACP, the software assigns a unique priority made up of these elements (in priority order): • LACP system priority • System ID (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. 31-14 Catalyst 2960 Switch Software Configuration Guide OL-8603-04

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31-14
Catalyst 2960 Switch Software Configuration Guide
OL-8603-04
Chapter 31
Configuring EtherChannels and Link-State Tracking
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. To every link between systems
that operate LACP, the software assigns a unique priority made up of these elements (in priority order):
LACP system priority
System ID (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 31-12
.
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