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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 14.1X53 for the EX Series.

Authentication and Access Control

  • LLDP neighbor port info display (EX4300 switches)—Starting with Junos OS Release 14.1X53-D40 for EX Series switches, the neighbor-port-info-display CLI statement is supported at the [edit protocols lldp] hierarchy level. You can use this statement to configure the type of LLDP neighbor port information that the switch displays in the Port info field in the output of the show lldp neighbors CLI command. By default, the Port info field in the output of the show lldp neighbors CLI command displays the port description TLV.

    [See neighbor-port-info-display.]

  • Increase in TACACS message length (EX Series)—Starting with Junos OS Release 14.1X53-D40, the length of TACACS messages allowed on Junos devices has been increased from 8150 to 65535 bytes.
  • Support for the accounting-port statement (EX Series)—Starting with Junos OS Release 14.1X53-D25, the accounting-port CLI statement is now supported at the [edit access radius-server server-address] hierarchy level on all EX Series switches. This command was supported only on EX4300, EX4600, and EX9200 switches in earlier Junos OS releases. The accounting-port statement enables you to specify the port on which to contact the RADIUS accounting server. The default port number is 1813, as specified in RFC 2866.

Dynamic Host Configuration Protocol

  • Format change for VLAN ID in DHCP Option 18—On EX4300 and EX4600 switches with DHCP snooping configured, when the VLAN ID is appended to the prefix of DHCP option 18, it will appear in decimal format instead of hexadecimal format.

Ethernet Switching

  • L2 Learning protocol—On QFX5100 Switches, the new parameter exclusive-mac mac is added to enhance the MAC move feature. This feature is used to track MAC addresses when they appear on a different physical interface or within a different unit of the same physical interface. When you configure the exclusive-mac mac parameter at the [edit protocols l2-learning global-mac-move] hierarchy level, the specified MAC address is excluded from the MAC move limit algorithm. The MAC address will not be tracked.

Interfaces and Chassis

  • On EX4300 switches, when you configure the DHCP relay-option-82 option, the circuit ID is added by default. In the case of an IRB interface, the DHCP relay option 82 will contain a description or name of the physical layer interface instead of the name of the IRB interface. To include the name of the IRB interface, you can use the include-irb-and-l2 statement. To display only the IRB interface without the names of the Layer 2 interface and VLAN, use the no-vlan-interface-name statement.


    VLAN-tagged interface


    Dual-tagged interface


    Pure Layer 3 interface


    IRB interface






    include-irb-and-l2 and use-vlan-id




    no-vlan-interface-name and use-vlan-id

    Mutually exclusive

    no-vlan-interface-name and include-irb-and-l2





    If no description found


    use-interface-description and use-vlan-id

    Mutually exclusive

    use-interface-description and include-irb-and-l2




    If no description found


    use-interface-description and no-vlan-interface-name



    If no description found


    use-interface-description, no-vlan-interface-name, and include-irb-and-l2


    If no description found


Routing Policy and Firewall Filters

  • Support for enhanced mask length on IPv6 destination-address match conditions for loopback filters (EX Series switches)—Starting with Junos OS Release 14.1X53-D15, the maximum mask length of IPv6 destination-address match conditions in loopback (lo0) filters on EX Series switches is /128.

Virtual Chassis and Virtual Chassis Fabric

  • New VCF multicast distribution tree configuration option—Starting with Junos OS Release 14.1X53-D35, a new Virtual Chassis Fabric (VCF) configuration option, fabric-tree-root, is available on EX Series and QFX Series devices in an autoprovisioned or preprovisioned VCF. This option changes how the VCF builds the multicast distribution trees (MDTs) used for forwarding and load-balancing broadcast, unknown unicast, and multicast (BUM) traffic within the VCF. By default, a VCF builds MDTs with each VCF member as the root of a tree, creating as many MDTs as members in the VCF. Setting the fabric-tree-root option for one or more members preempts this behavior. Instead, for each member configured with this option, the VCF only builds MDTs with those members as root nodes (referred to as the fabric tree roots). The recommended usage of this option is to set all spine devices in the VCF, and only spine devices, as fabric tree roots.

    Using this option avoids traffic interruption in a VCF when a leaf device becomes unavailable and the VCF needs to redistribute traffic within the VCF over the available MDTs. Using only spine-rooted MDTs provides a redistribution path to any destination leaf member directly through a spine member, and prevents traffic from flowing redundantly over paths to and from leaf members (which happens with leaf-rooted MDTs, creating excess traffic load in large VCFs).

  • Automatic software update (EX2200 Virtual Chassis)—Starting in Junos OS Release 14.1X53-D44, the automatic software update feature can be used to automatically update Junos software on members of an EX2200 Virtual Chassis running Junos OS Release 12.3R12 and later. Automatic software update is not supported on an EX2200 Virtual Chassis in releases prior to 14.1X53-D44.

Modified: 2017-11-29