NEC IP8800/S6300 User Manual

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3.   
Troubleshooting Functional Failures in Operation
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3.9
IPv6 Network Communication Failure
3.9.1
Communication Is Disabled or Is Disconnected
There are three possible causes that result in communication failure on the IPv6 network using this system.
1. Configuration on IPv6 communication has changed
2. Network configuration has changed
3. Network component failures
For 1 and 2 above, check for the differences in the configuration and network configuration provided before and after 
the change. Check for any difference disabling communication.
This section describes procedure to identify the failed part and to isolate the problem, mainly for the cases of "IPv6 
communication is disabled although the configuration and network configuration are correct." and "IPv6 
communication had been normally running but it is disabled now." as described in 3 above.
To locate the faulty part and cause, follow the flow below.
Figure 3-13: Failure Analysis Procedure When IPv6 Communication Disabled
<IPv6 communication disabled>
Verify if there is an occurrence of line failure using the show 
logging command.
No physical failure 
message exists.
A physical failure 
message exists.
Check the Up/Down status of the interface 
using the show ipv6 interface command.
see the manual "Message Log Reference"and 
perform the action described in [Action] 
associated with each log message.
Identify the extent of failure using the 
ping ipv6 command.
Go to "
."
Communication between the 
neighboring host and router 
is disabled.
Communication between the 
remote host and router is 
disabled.
Unicast communication
Solved 
Unresolve
The route 
information
exists. 
Verify the status of 
address resolution 
using the show ipv6 
neighbors command.
Verify the route 
information using the 
show ipv6 route 
command.
Verify RA address 
distribution.
Distributed
Not 
distributed
No route information exists or the 
next hop address is invalid.
Verify the IP network of 
remote system. Otherwise, go 
to "
."
Analyze the failure on each 
routing protocol. (RIPng, 
BGP4+, etc.)
Verify the filter 
settings.
Verify the RA 
settings.