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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

  • RPD slips are noticed on MX104 for customers that have large configuration load on the box with multiple services enabled ( for example, l2circuits, VPLS, L3VPN, firewall-filters configuration, SNMP-polling, and so on). The fFollowing should be considered to avoid RPD slips for longer time duration:

    Configure system config: delta-export, persist-groups-inheritance, fast-synchronize.

    Reduce configuration size.

    Remove any trace-options and reduce the logging pressure on the NAND-flash storage.

    Analyse the load from processes such as snmpd, mib2d, pfed processes if you are running SNMP. PR1361250

  • In case of SyncE signal loss, DPLL3 goes into holdover and still the DPLL1/SYNTH1 signal output will be driven to control board (CB). So we see the CB DPLL in locked state because of this INVALID QL is seen. The CLI output for current clock status is always taken from CB DPLL state, so we see the status as locked. This command output is as per design. This is a display issue but the functionality works fine. PR1509356

  • LFM might flap during MX Virtual Chassis ISSU to and from this release. PR1516744

  • When an image with the third party SDK upgrade (6.5.x) is installed, the CPU utilization might go up by around 5 percent. PR1534234

  • PTP to PTP noise transfer is passing for impairments profile 400nsp-p_1Hz, but failing for profile 400nsp-p_0.1Hz and lower bandwidth profiles as well. PR1543982

  • In cRPD, the CLI command to show system core files directly is not available. If there is a process crash or there are core files in cRPD, the user needs to log in to docker explicitly and check (periodically) /var/crash/ for any process crash or core file generation. This is a current limitation due to the absence of a CLI command to access /var/crash (of Docker) from cRPD. PR1546097

  • sFlow egress sampling of MPLS packets is not supported on MX Series platforms. PR1556659

  • Resource deadlock avoided message is observed during software addition. There is no functionality impact due to this message. PR1557468

  • On MX Series platforms, TTL value reported by sFlow egress sampling is equal to the TTL prior to decrement, that is, sFlow at ingress and sFlow at egress report the same value of TTL. PR1559565

  • The eODN feature supports up to 1000 SR-TE LSPs with 32000 express segment links in TED. PR1561947

  • RPD core file is generated during device reboot and/or daemon restart time. Daemon recovers and there is no service impact on routing protocol usage. Because of this, feature usage reporting for scale based licensed features in routing area will not be reported. PR1567043

  • Statistics for the traffic entering into the tunnel get incremented on the ingress FPC where traffic came in, and telemetry statistics get reported from ingress FPC. PR1567227

  • The PTP FPGA is kept in reset during BIOS boot. During Linux boot, the PTP FPGA is taken out of reset and pcie-tree is reenumerated. Hence you would be seeing the Link-up/down during this sequence. PR1572061

  • When unified ISSU is started, it is expected that the FPC restart will not be triggered by the user. If this is done, the ISSU can be aborted and system can be in-correct state. PR1572851

  • 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

  • To upgrade to Junos OS Release 21.2R1, you need to include the no-validate option when issuing the upgrade command.

    Junos OS releases prior to 20.4R1 do not support the no-validate option with unified ISSU. In order to upgrade from an older release to Junos OS Release 21.2R1 with unified ISSU, you must first upgrade to a release that supports the no-validate option for unified ISSU, such as 20.4R1. PR1568757


  • Image validation fails with the following message: mgd core @ _rs_init, _rs_stir, _rs_stir_if_needed. PR1568757


  • 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). PR1461468

  • With local reversion ON, there is a possibility of transit router not informing head-end of RSVP disabled link when link is flapped more than once. Work around is to remove local-reversion configuration. PR1576979

Platform and Infrastructure

  • With sensor being subscribed via Junos Telemetry Interface (JTI), after the interface is deleted, deactivated, or disabled, the TCP connection is still established, and the show agent sensors command still shows the subscription. PR1477790