NEC IP8800/S6300 User Manual

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3.   
Troubleshooting Functional Failures in Operation
119
3.18 Communication Failure on IEEE802.3ah/UDLD 
Function
3.18.1
Port Becomes Inactive Due to IEEE802.3ah/UDLD Function
If the port becomes inactive due to IEEE802.3ah/UDLD function, isolate the problem by following failure analysis 
methods shown in the table below.
Table 3-66: Failure Analysis Method When IEEE802.3ah/UDLD Function Is in Use
Note: 
IEEE802.3ah/OAM: OAM protocol specified by IEEE802.3ah.
IEEE802.3ah/UDLD: One-way link failure detection function specific to this system using IEEE802.3ah/OAM.
No.
Troubleshooting Steps and Command
Action
1
Use  the  show efmoam command to check the 
failure type of the port which becomes inactive 
due to IEEE802.3ah/UDLD function.
If "Down(loop)" is displayed in Link status, the network configuration which 
causes L2 loop may be adopted. Review the network configuration.
If "Down(uni-link)" is displayed in Link status, go to No. 2.
2
Check that IEEE802.3ah/OAM function is 
enabled in the opposite system.
If not enabled, enable IEEE802.3ah/OAM function in the opposite system.
If enabled, go to No. 3.
3
Execute the show efmoam statistics 
command to check the inhibited configuration 
is not adopted.
If Unstable of Info TLV has been incremented, the configuration inhibited 
for IEEE802.3ah/UDLD function may be adopted. Check that the physical 
port is connected to only one system.
If Unstable of Info TLV has not been incremented, go to No. 4.
4
Check that the system is directly connected to 
the opposite system.
If the system is connected through the media converter or hub, review the 
network configuration so that it is directly connected to the opposite system. 
If it cannot be avoided to use some relay equipment, use the media converter 
which enables the linkage status to be same at both sides (however, not 
recommended).
If the system is directly connected to the opposite system, go to No. 5.
5
Execute the show efmoam command to check 
the number of response timeout times for 
detecting the failure.
If the value of "udld-detection-count" is less than the initial value, the 
possibility that the one-way link failure is detected erroneously in spite of no 
actual failure is raised. Change the value of "udld-detection-count."
If the value of "udld-detection-count" exceeds the initial value, go to No. 6.
6
Check settings of the filter and QoS control.
Control frames (slow-protocol) used by IEEE802.3ah/UDLD function may 
have been discarded by filtering or QoS control. 
See "
" to check for it. If 
there is no problem, go to No. 7.
7
Test the line.
Test the line by referencing "
." If there is no problem, go to 
No. 8.
8
Check the cable.
Cable may be defective. Replace the cable used at the port.