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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

  • Upon MPC11 boot up, errors such as following might be seen, but these are harmless and does not have functional impact: timestamp device kernel: i2c i2c-100: (11/1:0x41) i2c transaction error (0x00000002) timestamp device kernel: i2c i2c-64: (7/1:0x41) i2c transaction error (0x00000002). PR1457655

  • Currently, we do not support IP options for egress firewall attach points. Relevant supporting document attached: opics/concept/firewall-filter-match-conditions-for-ipv4-traffic.html. The issue might cause IP-options router alert traffic not hitting the egress firewall filter. PR1490967

  • Once you configure VXLAN on an IFD, its always treated as vxlan port even though Layer 2 vlan exists. PR1570689

  • During reboot, warning: requires 'idp-sig' license spams screen. PR1594014

  • On all MX/SRX platforms, changing configuration AMS 1:1 warm-standby to load-balance or deterministic NAT might result in vmcore and cause traffic loss. PR1597386

  • The CPU might overrun while performing sanity check due to incompatibility issues between ukern scheduler and Linux driver, which might lead to traffic loss. PR1641517

  • Configuring MPC11 in 4x100G and keeping peer in 400G mode, link comes up on peer while staying down on local end. This issue is also specific to 400G-ZR optics as it has single media lane. The issue is not seen on other 400G optics supporting 4x100G mode. PR1653946


  • You can see the following IPC timeouts logs for statistics query to kernel (queried from CLI or daemons querying internally) when there is configuration churn, or large number of IPCs get exchanged between kernel and pfe in the system: if_pfe_msg_handler: pfe_peer_msg_handler error: <error> for msg type <type>, msg subtype <subtype>, opcode <op> and peer index <index> Default IPC timeout value in kernel for IPC statistics request is 10s. PR1629930

Interfaces and Chassis

  • MX240: Device prompt is not responding after issuing the commit command. PR1662883


  • With local reversion ON, there is a possibility of transit router not informing headend of RSVP disabled link when link is flapped more than once. As a workaround, remove local-reversion configuration. PR1576979

  • The automatic sorting of configuration entries do not work if defined under group. PR1637730

Platform and Infrastructure

  • In some scenarios with MPC, you might observe major alarm and error messages. This major error is triggered due to parity error, and the impacted queue might drop packets. This might impact the forwarding, and to recover, reboot the MPC card. PR1303489

  • On MX and EX9200 serial platforms, under Ethernet VPN (EVPN) environment, packets routed using IRB interface could not be fragmented due to media maximum transmission unit (MTU) problem. PR1522896

  • When the you apply deactivate services rpm and deactivate routing-options rpm-tracking and then commit, some of the rpm tracked added routes are not deleted from the routing table. As a workaround, perform the following steps:

    1. Deactivate routing-options rpm-tracking.

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

    3. Deactivate services rpm.

    4. Commit.


  • After a switchover event, when ppmd calls sendmsg system call to transmit the protocol packets, it gets blocked long enough that a few sendmsg calls cumulatively take up around 7 to 8 seconds. This indirectly impacts the BFD session because the BFD session has a Routing Engine-based detect time of 7.5 seconds to expire. PR1600684

Routing Policy and Firewall Filters

  • When you configure a hierarchy specified in apply-path in an ephemeral instance, then rpd may not be able to update the prefix-list for the configuration in ephemeral instance. PR1636390

Routing Protocols

  • When you have high scale, the Openconfig telemetry sensor /bgp-rib/ used in periodic streaming will cause high CPU usage by RPD. PR1625396