The customer reported that they consistently observe JTASK_SCHED_SLIP logs whenever the core-facing interfaces go down, either due to fiber-related issues or when they are intentionally disabled for maintenance purposes.
Aug 28 05:57:33 2025 labrouter mgd[28938]: UI_CMDLINE_READ_LINE: User 'labuser', command 'configure exclusive '
Aug 28 05:57:44 2025 labrouter mgd[28938]: UI_CMDLINE_READ_LINE: User 'labuser', command 'set interfaces ae21 disable '
Aug 28 05:58:02 2025 labrouter mgd[28938]: UI_CMDLINE_READ_LINE: User 'labuser', command 'commit '
Aug 28 05:58:09 2025 labrouter mib2d[14480]: SNMP_TRAP_LINK_DOWN: ifIndex 880, ifAdminStatus down(2), ifOperStatus down(2), ifName ae21
Aug 28 05:58:16 2025 labrouter rpd[14416]: RPD_LDP_NBRDOWN: LDP neighbor 96.34.XX.XXX (ae21.0) is down
Aug 28 05:58:16 2025 labrouter rpd[14416]: RPD_ISIS_ADJDOWN: IS-IS lost L1 adjacency to mcr11nwnngase on ae21.0, reason: Interface Down
Aug 28 05:58:16 2025 labrouter rpd[14416]: JTASK_SCHED_SLIP: 7 sec scheduler slip, user: 0 sec 952509 usec, system: 1 sec, 666061 usec
During our investigation, we observed that the customer had enabled PIM and other protocol traces with minimal flags. However, we noticed that the PIM trace files were rotating more aggressively than those of other protocols, particularly during core link status changes.
Although we initially recommended disabling traceoptions—highlighting that they should be used strictly for troubleshooting—the customer preferred to retain them as part of their standard configuration template.
To address the issue without disabling traceoptions, we proposed optimizing the trace file parameters. Specifically, we reduced the number of trace files from 5 to 2 and increased the file size from 1 MB to 25 MB. These changes effectively mitigated the issue, and the occurrence of JTASK_SCHED_SLIP logs was eliminated.
labuser@labrouter# show |compare
Sep 08 07:12:01
[edit protocols pim traceoptions]
- file pim_log size 1m files 5;
+ file pim_log size 25m files 2;
labuser@labrouter# commit and-quit comment "JTAC - Modifying PIM traces"
Sep 08 07:12:39
...
Sep 8 07:15:13 2025 labrouter kernel: lag_bundlestate_ifd_change: bundle ae21: bundle IFD minimum bandwidth or minimum links not met, Bandwidth (Current : Required) 1200000000000 : 1300000000000 Number of links (Current : Required) 12 : 13
Sep 8 07:15:13 2025 labrouter rpd[14416]: RPD_PIM_NBRDOWN: Instance PIM.master: PIM neighbor 96.34.XX.XXX (ae21.0) removed due to: the interface is purged
Sep 8 07:15:14 2025 labrouter rpd[14416]: RPD_LDP_NBRDOWN: LDP neighbor 96.34.XX.XXX (ae21.0) is down
Sep 8 07:15:14 2025 labrouter rpd[14416]: RPD_ISIS_ADJDOWN: IS-IS lost L1 adjacency to mcr11nwnngase on ae21.0, reason: Interface Down
Sep 8 07:15:15 2025 labrouter rpd[14416]: RPD_LDP_SESSIONDOWN: LDP session 96.34.XXX.XXX is down, reason: received notification from peer
Sep 8 07:15:29 2025 labrouter mib2d[14480]: SNMP_TRAP_LINK_DOWN: ifIndex 880, ifAdminStatus up(1), ifOperStatus down(2), ifName ae21
Sep 8 07:15:57 2025 labrouter rpd[14416]: RPD_LDP_NBRDOWN: LDP neighbor 96.34.XXX.XXX (lo0.0) is down
Sep 8 07:23:16 2025 labrouter kernel: lag_bundlestate_ifd_change: bundle ae21 is now Up. uplinks 26 >= min_links 13
Sep 8 07:23:16 2025 labrouter mib2d[14480]: SNMP_TRAP_LINK_UP: ifIndex 880, ifAdminStatus up(1), ifOperStatus up(1), ifName ae21