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Changes in Behavior and Syntax

This section lists the changes in behavior of Junos OS features and changes in the syntax of Junos OS statements and commands from Junos OS Release 14.2R8 for the PTX Series.

Class of Service (CoS)

  • Change to interpolated WRED drop probability (PTX Series)—In Junos OS Releases 13.2R4, 13.3R2, and 14.1 and later releases, the interpolated fill level of 0 percent has a drop probability of 0 percent for weighted random early detection (WRED). In earlier Junos OS releases, interpolated WRED can have a nonzero drop probability for a fill level of 0 percent, which can cause packets to be dropped even when the queue is not congested or the port is not oversubscribed.


  • IPv6 addresses with padded zeros in MIC or MS-MPC system log messages (PTX Series)—Starting with Junos OS Release 14.2R4, all system log messages originating from MIC or MS-MPC line cards displays padded zeros in IPv6 addresses to make them compatible with MS-DPC line cards. Earlier, the system log messages from MIC or MS-MPC line cards displayed IPv6 addresses with ’::’ instead of padded zeros.

Junos OS XML API and Scripting

  • Escaping of special XML characters required for request_login (PTX Series)—Beginning with Junos OS Release 14.2R4, you must escape any special characters in the username and password elements of a request_login XML RPC request. The following five symbols are considered special characters: greater than (>), less than (<), single quote (’), double quote (“), and ampersand (&). Both entity references and character references are acceptable escape sequence formats. For example, &amp; and &#38; are valid representations of an ampersand. Previously no escaping of these characters was required.


  • Support for status deprecated statement in YANG modules (PTX Series)—Starting in Junos OS Release 14.2R8, Juniper Networks YANG modules include the status deprecated statement to indicate configuration statements, commands, and options that are deprecated.


  • RSVP LSP Attribute Order Complies with RFC6510 (PTX Series)—The Junos OS RSVP PATH/RESV messages follow the recommendations made in RFC6510 for the LSP attribute order.

Network Management and Monitoring

  • New system log message indicating the difference in the Packet Forwarding Engine counter value (PTX Series)—In Junos OS Release 14.2R2 and later, if the counter value of a Packet Forwarding Engine is reported lesser than its previous value, then the residual counter value is added to the newly reported value only for that specific counter. In that case, the CLI shows the MIB2D_COUNTER_DECREASING system log message for that specific counter.


  • Enhancement for SONET interval counter (PTX Series)—Starting with Junos OS Release 14.2R6, only the Current Day Interval Total output field in the show interfaces interval command for SONET interfaces is reset after 24 hours. In addition, the Previous Day Interval Total output field displays the last updated time in hh:mm.

    [See show interfaces interval.]

  • Juniper MIBs Loading Errors Fixed (PTX Series)—Starting with Junos OS Release 14.2R8, duplicated entries and errors while loading MIBs on ManageEngine MIB browser are fixed for the following MIB files:
    • jnx-chas-defines.mib
    • jnx-gen-set.mib
    • jnx-ifotn.mib
    • jnx-optics.mib

    [See MIB Explorer.]

Routing Protocols

  • Modification to the default BGP extended community value (PTX Series)—Starting in Release 14.1, Junos OS has modified the default BGP extended community value used for MVPN IPv4 VRF route import (RT-import) to the IANA-standardized value. The default behavior has changed such that the behavior of the mvpn-iana-rt-import statement has become the default. The mvpn-iana-rt-import statement is deprecated and we recommend that you remove it from configurations.
  • OSPFv3-TTL propagation policy for TE-Shortcuts and FA-LSPs in line with other modules in the system (PTX Series)—Starting in Junos OS Release 14.2, the OSPFv3-TTL propagation policy is dictated by the MPLS-TTL propagation policy which, by default, allows propagation of TTL.

    This change makes the behavior of OSPFv3 in line with the default behavior of rest of the system, allowing you to disable TTL propagation for the above mentioned LSPs, and for traffic-engineering-shortcuts (TE-Shortcuts) and forwarding adjacency LSPs (FA-LSPs) using OSPFv3 as the IGP, by configuring the no-propagate-ttl statement at the [edit protocols mpls] hierarchy level.

User Interface and Configuration

  • Configuring regular expressions (PTX Series)—In all supported Junos OS releases, you can no longer configure regular expressions if they require more than 64 MB of memory or more than 256 recursions for parsing.

    This change in the behavior of Junos OS is in line with the FreeBSD limit. The change was made in response to a known consumption vulnerability that allows an attacker to cause a denial-of-service (resource exhaustion) attack by using regular expressions containing adjacent repetition operators or adjacent bounded repetitions. Junos OS uses regular expressions in several places within the CLI. Exploitation of this vulnerability can cause the Routing Engine to crash, leading to a partial denial of service. Repeated exploitation can result in an extended partial outage of services provided by the routing protocol process (rpd).

  • New warning message for the configurational changes to extend-size (PTX Series)—Starting with Junos OS Release 14.2R5, any operation on the system configuration-database extend-size configuration statement, such as, deactivate, delete, or set, generates the following warning message:

    Change in 'system configuration-database extend-size' will be effective at next reboot only.

Modified: 2017-12-12