Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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3. If communication with the remote device cannot be verified by using the ping ipv6
functionality, use the
ping ipv6 command to check communication with each of the devices
up to the remote device, beginning with the device closest to the customer's terminal.
4. If you are able to determine the range for the failure by using the
ping ipv6 functionality and
pinpoint the Switch that is likely to have the failure, log in to the Switch and investigate the
cause of the failure based on the failure analysis flowchart.
(5) Checking the NDP resolution information with a neighboring device
If the execution result of the
ping ipv6 command indicates that communication with a neighboring
device is impossible, the address might not have been resolved by NDP. To check the status of
address resolution between the Switch and the neighboring device, do the following:
1. Log in to the Switch.
2. Use the
show ipv6 neighbors command to check the status of address resolution (whether
NDP entry information exists) between the Switch and the neighboring device.
3. If the address with the neighboring device has been resolved (NDP entry information exists),
see (6) Checking the unicast interface information.
4. If the address has not been resolved (no NDP entry information exists), check whether the IP
network settings between the neighboring device and the Switch are identical.
(6) Checking the unicast interface information
You need to check the routing information obtained by the Switch if (a) communication is still
disabled after address resolution with the neighboring device is completed, (b) communication is
disabled on the route to the remote device during IPv6 unicast communication, or (c) the route to
the remote device has a problem. To carry out the check, do the following:
1. Log in to the Switch.
2. Execute the
show ipv6 route command to check the routing information obtained by the
Switch.
3. For AX6700S, AX6600S, and AX6300S series switches, check whether packets are discarded
at the null interface. If
null0 is displayed for the sending interface that caused the
communication failure in the routing information, packets are discarded at the null interface.
Check the setting conditions for the static routing functionality in the configuration.
4. If the routing information obtained by the Switch does not contain the routing information
about the interface that caused the communication failure or contains an incorrect address of
the interface's next hop, see 3.11 IPv6 unicast routing communication failures.
5. If the routing information obtained by the Switch contains routing information about the
interface that caused the communication failure, the interface might have a problem with the
functionality shown below. That functionality must be checked.
• RA functionality
See (8) Checking the RA configuration information.
(7) Checking the filters and QoS configuration information
Certain packets might have been discarded either by filtering or by bandwidth monitoring, drop
control, or the QoS control shaper.
Make sure that the setting conditions for filters and QoS control in the configuration are correct,
and that bandwidth monitoring, drop control, or the shaper is used appropriately in the system
configuration. For details about the procedure, see 3.25.1 Checking the filters and QoS
configuration information.
(8) Checking the RA configuration information
If communication between the Switch and a terminal directly connected to the Switch is not