Port Channel Channel Troubleshooting - Digitalchina Networks DCS-3950 series Manual

Displayed information
Port channels in the
group
Number of port
Standby port
17.4.1.2 debug lacp
Command: debug lacp
no debug lacp
Function: Enable the LACP debug function: 'no debug lacp' command disables this
debug function.
Command mode: Admin Mode
Default: LACP debug information is disabled by default.
Usage Guide: Use this command to enable LACP debugging so that LACP packet
processing information can be displayed.
Example: Enable LACP debugSwitch#debug lacp

17.4.2 Port Channel Channel Troubleshooting

If problems occur when configuring port aggregation, please first check the following for
causes.
Ensure all ports in a port group have the same properties, i.e., whether they are in
full-duplex mode, forced to the same speed, and have the same VLAN properties, etc.
If inconsistency occurs, make corrections.
Some commands cannot be used on a port in port-channel, such as arp, bandwidth, ip,
ip-forward, etc.
When port-channel is forced, as the aggregation is triggered manually, the port group
will stay unaggregated if aggregation fails due to inconsistent VLAN information. Ports
must be added to or removed from the group to trigger another aggregation, if VLAN
information inconsistency persists, the aggregation will fail again. The aggregation will
only succeed when VLAN information is consistent and aggregation is triggered due to
port addition or removal.
Verify that port group is configured in the partner end, and in the same configuration. If
the local end is set in manual aggregation or LACP, the same should be done in the
partner end; otherwise port aggregation will not work properly. Another thing to be
noted is that if both ends are configured with LACP, then at least one of them should
DCS-3950 series Ethernet switch manual
Explanation
If port-channel does not exist, the above information will not
be displayed.
Port number in the port-channel.
Port that is in 'standby' status, which means the port is
qualified to join the channel but cannot join the channel due to
the maximum port limit, thus the port status is 'standby'
instead of 'selected'.
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