3. Troubleshooting Functional Failures in Operation1193.18 Communication Failure on IEEE802.3ah/UDLDFunction3.18.1 Port Becomes Inactive Due to IEEE802.3ah/UDLD FunctionIf the port becomes inactive due to IEEE802.3ah/UDLD function, isolate the problem by following failure analysismethods shown in the table below.Table 3-66: Failure Analysis Method When IEEE802.3ah/UDLD Function Is in UseNote: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 Action1 Use the show efmoam command to check thefailure type of the port which becomes inactivedue to IEEE802.3ah/UDLD function.If "Down(loop)" is displayed in Link status, the network configuration whichcauses 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 isenabled 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 statisticscommand to check the inhibited configurationis not adopted.If Unstable of Info TLV has been incremented, the configuration inhibitedfor IEEE802.3ah/UDLD function may be adopted. Check that the physicalport 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 tothe opposite system.If the system is connected through the media converter or hub, review thenetwork configuration so that it is directly connected to the opposite system.If it cannot be avoided to use some relay equipment, use the media converterwhich enables the linkage status to be same at both sides (however, notrecommended).If the system is directly connected to the opposite system, go to No. 5.5 Execute the show efmoam command to checkthe number of response timeout times fordetecting the failure.If the value of "udld-detection-count" is less than the initial value, thepossibility that the one-way link failure is detected erroneously in spite of noactual 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 mayhave been discarded by filtering or QoS control.See "3.23.1 Checking Filtering/QoS Setting Information" to check for it. Ifthere is no problem, go to No. 7.7 Test the line. Test the line by referencing "6.1 Testing Line." If there is no problem, go toNo. 8.8 Check the cable. Cable may be defective. Replace the cable used at the port.
