Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
135
Table 3-72: Failure analysis method for uplink redundancy
No. Items to check and commands Action
1 Execute the
show
switchport-backup command,
and make sure that the states of the
primary and secondary ports are
Forwarding or Blocking correctly.
If neither the primary port nor the secondary port is
Forwarding, check
the following:
• If both of them are
Blocking, active port locking might be enabled.
Execute the show switchport-backup command, and check
whether active port locking is operating. If active port locking is
operating, wait a while until the primary port is linked up.
Alternatively, use the
set switchport-backup active command
to activate the secondary port.
• If
Down is displayed, check the line status. For details about the check
procedure, see 3.5 Network interface communication failures.
If there is no problem with the
Forwarding or Blocking state of the
devices, go to No. 2.
2 Check the upstream devices for the
uplink redundancy.
If the upstream devices do not support the flush control frame reception
functionality, check whether the MAC address update functionality is
enabled on the device that uses the uplink redundancy. The MAC address
update functionality might be disabled or the network configuration
might not allow MAC address update frames to be received. In such a
case, if switchover or switchback occurs due to uplink redundancy,
communication of the upstream devices is not restored until the MAC
address table is aged out. If this is the case, wait a while and check the
communication status again. Alternatively, clear the MAC address table
on the upstream devices.
If the upstream devices support the flush control frame reception
functionality, go to No. 3.
3 Check whether the settings are correct
for the VLAN to which flush control
frames are sent.
Execute the
show switchport-backup command, and make sure that
the VLAN to which flush control frames are sent is displayed as specified
in the configuration.
If expected information is not displayed, the settings in the configuration
are not correct. Check the settings of the VLAN to which flush control
frames are sent and the VLAN settings for the primary and secondary
ports in the configuration.
If the settings are correct for the VLAN to which flush control frames are
sent, go to No. 4.
4 Make sure that the upstream devices
can receive flush control frames.
Execute the
show logging command, and make sure that the upstream
devices can receive flush control frames. If the upstream devices cannot
receive flush control frames, check whether a VLAN that can receive
flush control frames has been set.