Description

        et-10/1/0 ---
MX                      ae1 ----ae3  PTX
       et-10/3/0 ---
ISIS was flapping on ae1, but the ae1 member interfaces were not flapping, and those interfaces did not have output errors.

Symptoms

MX960> show log messages | match isis  
Aug 29 20:30:08
<29>1 2023-08-29T03:16:19.943Z MX960 rpd 3911 RPD_ISIS_ADJDOWN [[email protected] isis-level="1" neighbor-system-id="PTX" interface-name="ae1.0" reason="Aged out"] IS-IS lost L1 adjacency to PTX on ae1.0, reason: Aged out
<30>1 2023-08-29T03:16:19.949Z MX960 rpd 3911 RPD_ISIS_ADJUP [[email protected] isis-level="1" neighbor-system-id="PTX" interface-name="ae1.0"] IS-IS new L1 adjacency to PTX on ae1.0
<29>1 2023-08-29T03:19:44.887Z MX960 rpd 3911 RPD_ISIS_ADJDOWN [[email protected] isis-level="1" neighbor-system-id="PTX" interface-name="ae1.0" reason="Aged out"] IS-IS lost L1 adjacency to PTX on ae1.0, reason: Aged out
<30>1 2023-08-29T03:19:44.892Z MX960 rpd 3911 RPD_ISIS_ADJUP [[email protected] isis-level="1" neighbor-system-id="PTX" interface-name="ae1.0"] IS-IS new L1 adjacency to PTX on ae1.0
<29>1 2023-08-29T04:21:54.908Z MX9602 rpd 3911 RPD_ISIS_ADJDOWN [[email protected] isis-level="1" neighbor-system-id="PTX" interface-name="ae1.0" reason="Aged out"] IS-IS lost L1 adjacency to PTX on ae1.0, reason: Aged out
 
user@MX960> show chassis routing-engine no-forwarding
Routing Engine status:
 Slot 0:
  Current state         Master
  Election priority       Master (default)
  Temperature         32 degrees C / 89 degrees F
  CPU temperature       31 degrees C / 87 degrees F
  DRAM           16330 MB (16384 MB installed)
  Memory utilization     20 percent
  5 sec CPU utilization:
   User            2 percent
   Background         0 percent
   Kernel           4 percent
   Interrupt         1 percent
   Idle           94 percent
  1 min CPU utilization:
   User            1 percent
   Background         0 percent
   Kernel           4 percent
   Interrupt         1 percent
   Idle           94 percent
  5 min CPU utilization:
   User            1 percent
   Background         0 percent
   Kernel           3 percent
   Interrupt         1 percent
   Idle           94 percent
  15 min CPU utilization:
   User            1 percent
   Background         0 percent
   Kernel           3 percent
   Interrupt         1 percent
   Idle           94 percent
  Model             RE-S-1800x4
  Serial ID           9009163503
  Start time           2022-03-11 09:29:00 UTC
  Uptime             536 days, 12 hours, 16 minutes, 25 seconds
  Last reboot reason       Router rebooted after a normal shutdown.
  Load averages:         1 minute  5 minute 15 minute
                    0.37    0.33    0.32
Routing Engine status:
 Slot 1:
  Current state         Backup
  Election priority       Backup (default)
  Temperature         31 degrees C / 87 degrees F
  CPU temperature       30 degrees C / 86 degrees F
  DRAM           16331 MB (16384 MB installed)
  Memory utilization     19 percent
  5 sec CPU utilization:
   User            0 percent
   Background         0 percent
   Kernel           1 percent
   Interrupt         0 percent
   Idle           99 percent
  Model             RE-S-1800x4
  Serial ID           9009089047
  Start time           2022-03-11 09:30:07 UTC
  Uptime             536 days, 12 hours, 15 minutes, 5 seconds
  Last reboot reason       Router rebooted after a normal shutdown.
  Load averages:         1 minute  5 minute 15 minute
                    0.23    0.17    0.15
Logical interface ae1.0 (Index 331) (SNMP ifIndex 762) (Generation 343)
  Flags: Up SNMP-Traps 0x4004000 Encapsulation: ENET2
  Statistics    Packets    pps     Bytes     bps
  Bundle:
    Input :     5115     1    607336     2208
    Output:      579     0     47067      0
  Adaptive Statistics:
    Adaptive Adjusts:     0
    Adaptive Scans :     0
    Adaptive Updates:     0
  Link:
   et-10/1/0.0
    Input :     2803     1    320648     1224
    Output:      579     0     47067      0
   et-10/3/0.0
    Input :     2312     0    286688     984
    Output:       0     0       0      0
 

Solution

The isis flapping symptom may be an issue external to the MX. As the member interfaces of the ae bundle did not have any flaps or output errors, Layer one troubleshooting can be done to check the fibers and transport path.
If the issue persists, please contact JTAC for additional assistance. 

Modification History

2023-09-05:Initial Publication.