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Known Behavior


This section contains the known behavior, system maximums, and limitations in hardware and software in Junos OS Release 15.1R7 for the M Series, MX Series, and T Series.

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


  • Support for MIC-3D-8OC3-2OC12-ATM Revision 22 and later—MIC-3D-8OC3-2OC12-ATM Revision 22 is supported only by the following Junos OS releases:

    • Junos OS Release 12.3—12.3R9 and later

    • Junos OS Release 13.3—13.3R6 and later

    • Junos OS Release 14.1—14.1R4 and later

    • Junos OS Release 14.2—14.2R3 and later

    • Junos OS Release 15.1 and later

    You must upgrade to a supported Junos OS release to use MIC-3D-8OC3-2OC12-ATM Revision 22 and later.

  • The options alarm low-light-alarm and warning low-light-warning might not work (MX Series)—The alarm low-light-alarm and warning low-light-warning options at the [edit interfaces interface-name optics-options] hierarchy level might not work for the 10-Gigabit Ethernet and 100-Gigabit Ethernet interfaces of MPC3, MPC4, MPC5, MPC6, MPC7E, MPC8E, and MPC9E on MX Series 5G Universal Routing Platforms. These options might not work on MPC3E-3D-NG, MPC3E-3D-NG-Q, MPC2E-3D-NG, and MPC2E-3D-NG-Q if they are installed with Junos Continuity software.

    This is a known behavior and has no impact on the performance of these line cards.

Forwarding and Sampling

  • Improved Packet Forward Engine performance (MX Series)--Starting in Junos OS Release 15.1R5,, a new mechanism is added to the Packet Forwarding Engine to improve forwarding performance. A noticeable behavior of the mechanism is to increase the CPU utilization periodically.

Interfaces and Chassis

  • Reordering of MAC addresses after a Routing Engine switchover—In Junos OS Release 14.2 and later, if you configure multiple aggregated Ethernet interfaces, the MAC address of the aggregated Ethernet interfaces displayed in the show interfaces ae number command output might get reordered after a Routing Engine switchover or restart.

    As a workaround, you can configure static MAC addresses for aggregated Ethernet interfaces. Any external dependency, such as filtering of the MAC addresses that are assigned before the reboot, becomes invalid if the MAC address changes.


  • Removal of SRLG details from the SRLG table only on the next reoptimization of the LSP–If an SRLG is associated with a link used by an ingress LSP in the router, then on deleting the SRLG configuration from that router, the SRLG gets removed from the SRLG table only on the next reoptimization of the LSP. Until then, the output displays Unknown-XXX instead of the SRLG name and a nonzero srlg-cost of that SRLG for run show mpls srlg command.

  • With the introduction of the multi-instance support for LDP-over-RSVP LSPs, you cannot enable MPLS on an interface that is already assigned to another routing instance. Starting in Junos OS Release 15.1R1, adding an interface that is part of another routing instance at the [edit protocols mpls] hierarchy level, throws a configuration error at the time of commit.

Network Management and Monitoring

  • Specified MIBS are not supported in Junos OS (MX Series)—As of Junos OS Release 15.1, the following MIBS are not supported in Junos OS: CfmMepErrorCcmLastFailure, CfmMepXconCcmLastFailure, CfmMepCcmSequenceErrors, and ieee8021CfmMaCompNumberOfVids.

Routing Policy and Firewall Filters

  • When upgrading a MX240, MX480, MX960, MX2010, or MX2020 Series router to Junos OS Release 15.1R4, 15.1R5, or 15.1R6, the existing firewall filters on the uplink interfaces may not be applied as expected if the device is rebooted. Templates and non-interface specific filters are not affected. To work around the issue, save the configuration using the commit-full command (which triggers all the Junos daemons to evaluate the new configuration rather than the corresponding daemons only).

Subscriber Management and Services (MX Series)

  • Junos OS Release 15.1R3 provides feature parity with the Junos OS Release 13.3R1 subscriber management feature set with the following exceptions:

    • Subscriber management is supported in the default logical system only.

    • TCP connections terminated by the router are supported for statically configured logical interfaces only. These connections are not supported on dynamically configured logical interfaces (for example, those using broadband edge dynamic-profiles).

    • Bandwidth provisioning based on DHCP option82 is not supported.

    • The dscp-code-point statement at the [edit class-of-service host-outbound-traffic] hierarchy level is not supported.

    • You cannot use the subscriber management configuration used for multicast dynamic cos-adjust with previous versions of Junos OS.

    • Reverse outgoing interface (OIF) mapping, which enables the router to propagate the multicast state of the shared interface to the customer interfaces and enables per-customer accounting and QoS adjustments, is not available.

    • Fast update filters for dynamic profiles, which you can use to incrementally add, remove, or update filter terms, are not supported.

    • Lawful intercept of multicast traffic is not supported.

    • Advisory speed reporting to a RADIUS server and to an L2TP network server (LNS) is not supported.

    • Access Node Control Protocol (ANCP) is not supported.

    • The use of the per-unit-scheduler statement at the [edit interfaces interface-name] hierarchy level is not supported for subscribers. Subscribers associated with this option do not appear.

    • C-VLAN logical interfaces do not inherit the Ethernet Operation, Administration, and Maintenance (OAM) statuses from the associated S-VLAN logical interfaces.

    • MS-DPCs are not supported.

    • Static PPPoE interfaces are not supported.

    • N-Way active targeting over aggregated Ethernet member links is not supported.

    • Targeted distribution of static or dynamic interface sets over aggregated Ethernet is not supported.

  • The show ppp interface interface-name extensive and show interfaces pp0 commands display different values for the LCP state of a tunneled subscriber on the LAC. The show ppp interface interface-name extensive command displays STOPPED whereas the show interfaces pp0 command displays OPENED (which reflects the LCP state before tunneling). As a workaround, use the show ppp interface interface-name extensive command to determine the correct LCP state for the subscriber.

  • On MX Series routers, when you configure the subscriber-awareness statement on a service set by committing the set services service-set service-set-name service-set-options subscriber-awareness statement, the service sessions fail to create. To avoid this issue, on MX Series routers that support the Service Control Gateway solution, ensure that the Junos OS Mobility package software is installed on the router.

    The Service Control Gateway solution is supported only in 14.1X55 releases. For Junos OS Releases 14.2, 15.1, and 16.1 ensure that the subscriber-awareness statement is not set.

  • Support for multicast group membership in Enhanced Subscriber Manager (MX Series)— In Junos OS Release 15.1R3, enhanced subscriber management does not support the use of dynamic profiles for the static configuration of multicast group membership for subscribers. Instead, subscribers must send an IGMP JOIN message to receive the multicast stream. More specifically, the following command is not supported in this release:

    set dynamic-profiles client profile protocols igmp interface $junos-interface-name static group

  • Dynamic provisioning in Layer 2 wholesaling (MX Series)—Starting with Release 15.1R3, Junos OS does not support dynamic VLAN mapping into VPLS instances. (You can still configure static VLAN interface mapping to VPLS instances.) By extension, dynamic provisioning for Layer 2 wholesaling is also not supported in this release.

    The following example shows the statements that are not currently available (encapsulation vlan-vpls and family vplsat the [edit dynamic interfaces] hierarchy level):

  • Preventing Link Aggregation Control Protocol link reversion in a scaled configuration (MX Series)—By default, LACP link protection is revertive. This means that after the current link becomes active, the router switches to a higher-priority link if one becomes operational or is added to the aggregated Ethernet bundle. In a highly scaled configuration over aggregated Ethernet, we recommend that you prevent the router from performing such a switch by including the non-revertive statement at the [edit chassis aggregated-devices ethernet lacp link-protection] hierarchy level. Failure to do so may result in some traffic loss if a MIC on which a member interface is located reboots. Using the non-revertive statement for this purpose is not effective if both the primary and secondary interfaces are on the MIC that reboots.

  • Support for stacked IFL configurations (MX Series)— Junos OS release 15.1R4 does not provide complete support for the interface variable, $junos-interface-ifd-name, with stacked IFL configurations such as PPPoE. Juniper recommends using Junos OS release 15.1R5 or later if you need to reference more than one IFD within a dynamic profile (in other words, to stack IFLs in support of certain CoS configurations in conjunction with subscriber management).

  • The all option is not intended to be used as a means to perform a bulk logout of L2TP subscribers. We recommend that you do not use the all option with the clear services l2tp destination, clear services l2tp session, or clear services l2tp tunnel statements in a production environment. Instead of clearing all subscribers at once, consider clearing subscribers in smaller group, based on interface, tunnel, or destination end point.

System Logging

  • Text string deprecated in syslog messages that are converted to SNMP traps (M Series, MX Series, and T Series)—In the syslog messages that are converted to SNMP traps for event policies, the "trap sent successfully" text string is deprecated.

  • On MX Series routers, when you configure a rate limit for system log messages by setting the message-rate-limit statement for a multiservices interface, ensure that the syslog host option for that interface is configured. This configuration ensures that the system log statistics reflect the rate limit set for the interface.


  • Default export EVPN policy has been removed (MX Series)—Starting in Junos OS Release 15.1R5 and forward, the hidden default EVPN export policy statement (evpn-pplb) has been removed. To enable and configure load balance per packet for EVPN and PBB-EVPN, use the existing policy statements:

    • set routing-options forwarding-table export evpn-pplb

    • set policy-options policy-statement evpn-pplb from protocol evpn

    • set policy-options policy-statement evpn-pplb then load-balance per-packet


    To support EVPN multihoming, you must configure the load-balance per-packet statement.