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Known Limitations

Learn about known limitations in this release for MX Series routers.

For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • The ping latency behavior is expected for host generated ICMP traffic because of the Packet Forwarding Engine design queue polling the packets from ASIC. PR1380145

  • The interface hold-down timer cannot be achieved for less than 15 seconds on the MPC11E line card. The interface on MPC11E might go down if the peer link goes down and downtime is less than 15 seconds. PR1444516

  • MX-SyncE lock status shows LOCKED under the chassis synchronization extensive command when synchronization Ethernet source fails with the DUT configured with G.8275.1 profile. PR1509356

  • Changing the scaled firewall profiles on the fly does not release the TCAM resources as expected. PR1512242

  • LFM might flap during the MX Series Virtual Chassis ISSU. PR1516744

  • Running "help apropos" command in configuration mode might generate a MGD core file. PR1552191

  • On MX Series routers, unified ISSU or upgrade with validate option might fail if there is too less disk space in /var/tmp/. It is recommended to clear out all log files and core files before initiating upgrade with validate option (that is, when you are not using no-validate option) or unified ISSU. It is better to clear all unwanted data using request system storage cleanup to cleanup all unwanted data. You must ensure there is at least 9 GB free space in var/tmp after copying vmhost package file to /var/tmp/.PR1582554

  • When a packet, which triggers ARP resolution, hits services interface style filter on the output will have session create and close log with incorrect ingress interface. This typically occurs with the first session hitting such a filter. PR1597864

  • Errors do not appear until there is a composite nexthop with two labels in the nexthop. This scenario must not appear and there is no impact in behavior. PR1621689


  • Image v-Ѵb7-ঞon fails with the following message: mgd core @ _rs_init, _rs_stir, _rs_stir_if_needed. PR1568757

  • The Junos OS Release 21.1 and earlier are running FreeBSD version whereas from Junos OS Release 21.2 and later runs the FreeBSD 12. Upgrading to Junos OS release 21.2 or later from Junos OS Release 21.1 or earlier will mandatorily need configuration statement no-validate to be used during software image upgrade process. PR1586481


  • Rpd process might crash after network service configuration changed (example, range of MPLS labels) without rebooting all the Routing Engines (which is a system mandatory step).


Network Management and Monitoring

  • Configuring set system no-hidden-commands blocks/denies netconf/junoscript sessions. As a workaround, delete system no-hidden-commands configuration statement and start the netconf/junoscript sessions. PR1590350

Platform and Infrastructure

  • MPC equipped with QX-chip might completely stop forwarding traffic after QX-chip internal memory error and MQChip DDRIF WO checksum error. PR1197475

  • Below error logs are seen, while running clear vpls mac-table. [Mar 9 06:20:42.795 LOG: Err] disp_force_callout(1994): EA[0:0].disp[0] forced callout timeout 0 msec. [Mar 9 06:20:42.795 LOG: Err] luss_send_callout_parcel(793): EA[0:0].disp[0] failed to send callout parcel (ptype 14, snum 977 tid 0). [Mar 9 06:20:43.510 LOG: Err] dispatch_event_handler(684): EA[0:0].disp[0] PRIMARY_TIMEOUT (PPE 4 Zone 8). Impact: There will not be any functional impact during this issue, just the error logs. It occurs with a scaled count of more than 1.5L MACs and eventually all the MACs will get cleared successfully. PR1575316

  • When deactivate services rpm and deactivate routing-options rpm-tracking commands are applied together and committed, some of the rpm tracked added routes are not deleted from the routing table. The issue cannot be seen when using the following steps:

    1. Issue the deactivate routing-options rpm-tracking command.

    2. Commit the configuration, then all the rpm tracked routes will be deleted.

    3. If the RPM service needs to be deactivated, issue the deactivate services rpm and commit. PR1597190

Routing Protocols

  • If you do not issue the restart routing command after configuring the enhanced IP might result in a label inconsistency that causes the device to generate a rpd core file. PR1577451