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Known Behavior


This section contains the known behavior, system maximums, and limitations in hardware and software in Junos OS Release 15.1F7 for the MX Series.


  • 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 3D Universal Edge Routers. 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.

General Routing

  • The following request commands are not available for the Routing Engine RE-S-X6-64G on the MX240, MX480, MX960, MX2010, and MX2020:

    • request system halt

    • request system partition

    • request system power off

    • request system power on

    The scope of functionality of the following commands is limited to Junos OS guest level:

    • request system reboot

    • request system snapshot

    • request system software add

    • request system zeroize

    You can use the following equivalent request vmhost commands to achieve the functionality:

    • request vmhost cleanup

    • request vmhost file-copy

    • request vmhost halt

    • request vmhost hard-disk-test

    • request vmhost power-off

    • request vmhost power-on

    • request vmhost reboot

    • request vmhost snapshot

    • request vmhost software abort

    • request vmhost software add

    • request vmhost software in-service-upgrade

    • request vmhost software rollback

    • request vmhost zeroize

    The output of the following show commands are modified for the Routing Engine RE-S-X6-64G:

    • show chassis environment routing-engine

    • show chassis hardware

    • show chassis hardware extensive

    • show chassis routing-engine

    • show system software

    The following new show commands are introduced for the Routing Engine RE-S-X6-64G:

    • show vmhost bridge

    • show vmhost crash

    • show vmhost hardware

    • show vmhost information

    • show vmhost logs

    • show vmhost netstat

    • show vmhost processes

    • show vmhost resource-usage

    • show vmhost snapshot

    • show vmhost status

    • show vmhost uptime

    • show vmhost version

    The following new configuration statements are introduced for the Routing Engine RE-S-X6-64G:

    • edit system processes app-engine-virtual-machine-management-service

    • edit vmhost

  • During deletion and restoration of scaled configurations on MX240, MX480, MX960, MX2010, and MX2020, error messages related to next hops are displayed.

  • During graceful Routing Engine switchover (GRES) on MX240, MX480, MX960, MX2010, and MX2020, the 802.1x daemon crashes if the number of logical interfaces configured is equal to 64,000 or more. After the crash, the daemon restarts and resumes normal operations.

  • The configuration of the smartd process, which monitors the status of the disk on the host OS of MX240, MX480, MX960, MX2010, and MX2020, is not deleted completely even after you delete the configuration. When you configure the smart check feature, smartd continues to use parameters that were configured previously. Therefore, while enabling smart check, remember to configure the threshold values for smartd instead of retaining the default values that were previously configured.

  • FIFO handles of SSD-monitoring smartd are not cleared on the host OS after multiple commits or checks. Smartd stops working when the FIFO limit reaches a maximum. Therefore, we recommend that you do not change smartd configurations too often and perform SSD smart checks after long intervals of time. When the FIFO limit reaches a maximum, reboot the host OS.

  • In a dual Routing Engine system, while Junos OS has just started booting in the master Routing Engine, the backup Routing Engine might be powered-off if it is removed and reinserted.

    As a workaround, plug in the backup Routing Engine after master Routing Engine is running stable and all the FPCs are in operational state. If the other Routing Engine gets powered-off accidentally, issue the commands request chassis cb slot number power off and request chassis cb slot number power on to turn the power on the Routing Engine. The slot number signifies the Routing Engine that has to be powered-on.

  • The date and time zones are synchronized from the admin guest Junos OS to host OS on the MX240, MX480, MX960, MX2010, and MX2020 and use same time zones. Therefore, there is no difference in the timestamp in system log files of Junos OS and the host OS.

Interfaces and Chassis

  • Starting in Junos OS Release 15.1F4, when interfaces are disabled on MPC7, the output of the show interfaces diagnostic optics command displays the following information under lane characteristics:


  • The configuration flow-label-transmit and flow-label-receive statements are not supported in OAM CFM session over L2Circuit.


  • On MX Series routers running OpenFlow v1.3.1 or later, a group in which the same output port is specified for multiple buckets is not supported.

Services Applications

  • The MS-MPC cannot support the route scale of other MPCs because the MS-MPC does not have as much memory as other MPCs.

Subscriber Management and Services (MX Series)

  • By default, Link Aggregation Control Protocol 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.

  • Dynamic firewall filter match conditions for enhanced subscriber management (MX Series)—Enhanced subscriber management does not support dynamic firewall filter match conditions that consist of an interface identifier and an * (asterisk) wildcard character, such as interface pp0.* or interface demux0.*. If you use interface specifications with wildcards as match conditions, the match results do not include dynamic subscriber interfaces created with enhanced subscriber management. However, interface specifications that use a wildcard character continue to be supported for statically configured interfaces.

    In earlier Junos OS releases, match conditions consisting of an interface identifier and an * (asterisk) wildcard character are supported for both dynamically configured and statically configured interfaces.

  • Support for multicast group membership in Enhanced Subscriber Manager (MX Series)— In Junos OS Release 15.1F5, 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 however still configure static VLAN interface mapping to VPLS instances). By extension, this means that dynamic provisioning for Layer 2 wholesaling is also not supported in the current release. Note that dynamic provisioning in layer 2 wholesaling is not being dropped from Junos; support is slated to return in a future release.

    The following sample shows the exact commands that are not currently available (encapsulation VLAN-VPLS, and family VPLS, under the dynamic interfaces hierarchy):

User Interface and Configuration

  • Modification to configurable link degrade threshold values (MX Series)—Starting with Junos OS Release 15.1F7, the values of the user configurable link degrade thresholds, have to be configured as per the following guidelines:

    • set threshold value must be greater than warning set threshold value

    • set threshold value must be greater than clear threshold value

    • warning set threshold value must be greater than warning clear threshold value

    If the threshold values are not configured as per these guidelines, the configuration fails and a Commit Error message is displayed.