Description

The oam ethernet link-fault-management is not working as expected on an interface with vlan-tagging enabled.

Symptoms

The oam ethernet link-fault-management is not working as expected, as seen in this output: 

user@PTX5000> show oam ethernet link-fault-management et-3/0/0
Interface: et-3/0/0
Status: Down
Loopback tracking: Disabled, Loop status: Unknown
Detect LOC: Disabled, LOC status: Unknown

The interface is up however. 

{master}
user@PTX5000> show interfaces et-3/0/0 terse 
Interface               Admin Link Proto    Local                 Remote
et-3/0/0                up    up
et-3/0/0.102            up    up   inet     10.10.121.30/31
                                   mpls    
                                   multiservice

Solution

When vlan-tagging is enabled, the unit 32767 should be automatically created. Unit 32767 is not created with the configuration. 
OAM ethernet link-fault-management will then run over this unit 32767. 

Here is a working interface: 

labuser@PTX5000-re0> show interfaces et-4/1/18 terse                      
Interface               Admin Link Proto    Local                 Remote
et-4/1/18               up    up
et-4/1/18.102           up    up   inet     10.10.10.30/31  
                                   mpls    
                                   multiservice
et-4/1/18.32767         up    up   multiservice

Note that unit 32767 is seen in the output above. 

user@PTX5000-2> show oam ethernet link-fault-management et-4/1/18 
  Interface: et-4/1/18
    Status: Running, Discovery state: Send Any
    Transmit interval: 1000ms, PDU threshold: 10 frames, Hold time: 10000ms
    Peer address: d8:18:d3:b3:6d:ed
    Flags:Remote-Stable Remote-State-Valid Local-Stable 0x50
    Loopback tracking: Disabled, Loop status: Unknown
    Detect LOC: Disabled, LOC status: Unknown
    Remote entity information:
      Remote MUX action: forwarding, Remote parser action: forwarding
      Discovery mode: active, Unidirectional mode: unsupported
      Remote loopback mode: unsupported, Link events: supported
      Variable requests: unsupported
 

Useful troubleshooting outputs include: 

show interface et-a/b/c (note the interface index for unit 32767)
show ppm adjacencies protocol lfm detail (check if the unit 32767 interface index is there)

In config mode: 

set interfaces et-a/b/c traceoptions flag all  (this logging can be seen with "show log dcd")

Then commit this change. Be sure to turn off these traceoptions when done troubleshooting. 

 

Example where unit 32767 has interface index 96, and IFL-index: 96 is seen in "show ppm adjacencies protocol lfm detail":

user@PTX5000-2> show interfaces et-4/1/18 | match 32767 
  Logical interface et-4/1/18.32767 (Index 96) (SNMP ifIndex 902)

user@PTX5000-2> show interfaces et-4/1/18 | match Index                
  Interface index: 500, SNMP ifIndex: 896
  Logical interface et-4/1/18.102 (Index 95) (SNMP ifIndex 845)
  Logical interface et-4/1/18.32767 (Index 96) (SNMP ifIndex 902)

user@PTX5000-2> show ppm adjacencies protocol lfm detail               
Protocol: LFM, Hold time: 10000, IFL-index: 96
Distributed: TRUE
Distribution handle: 8268, Distribution address: fpc4

Adjacencies: 1, Remote adjacencies: 1
 

To resolve the issue, restart the ethernet-link-fault-management process during a maintenance window.

restart ethernet-link-fault-management

It may be necessary to offline/online the FPC to clear the issue. 

If further assistance is needed, please contact your JTAC representative. 

Modification History

2022-09-16: Publish