Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Navigation  Back up to About Overview 
[+] Expand All
[-] Collapse All

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 QFX Series.

Authentication and Access Control

  • Increase in TACACS message length (QFX 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.

Interfaces and Chassis

  • ARP and MAC table synchronization during MC-LAG troubleshooting (QFX Series switches and EX4300 switches)—Starting in Junos OS Release 14.1X53-D40, the arp-l2-validate CLI statement is supported at the [edit interfaces irb] hierarchy level for QFX Series switches and EX4300 switches. This command can be used to help maintain ARP and MAC table synchronization in an MC-LAG to prevent traffic loss while troubleshooting network problems that cause inconsistencies between the two tables.

    [See TroubleshootingMultichassis Link Aggregation and arp-l2-validate.]

  • Configuring unified forwarding table profiles (EX4600 Virtual Chassis, QFX5100 Virtual Chassis, and QFX Series Virtual Chassis Fabric)—Starting in Junos OS Release 14.1X53-D40, Packet Forwarding Engines on switches in a Virtual Chassis or Virtual Chassis Fabric (VCF) do not automatically restart upon configuring and committing a unified forwarding table profile change using the set chassis forwarding-options statement. Instead, a message is displayed at the CLI prompt and logged to the switch’s system log, prompting you to reboot the Virtual Chassis or VCF for the change to take effect. This change avoids Virtual Chassis or VCF instability that might occur with these switches if the profile update propagates to member switches and otherwise causes multiple Packet Forwarding Engines to automatically restart at the same time. This behavior change does not apply to other switch types or to EX4600 and QFX5100 switches not in a Virtual Chassis or VCF; in those cases, the switch continues to restart automatically when a unified forwarding table profile change is committed.

    We recommend that you plan to make profile changes in a Virtual Chassis or VCF comprised of these switches only when you can perform a Virtual Chassis or VCF system reboot shortly after committing the configuration update, to avoid instability if one or more member switches restart unexpectedly with the new configuration (while the remaining members are still running the old configuration).

    [See Configuring the Unified Routing Table and forwarding-options (chassis).]

  • New vc-path command display for Virtual Chassis Fabric (VCF)—Starting in Junos OS Release 14.1X53-D40, the output from the show virtual-chassis vc-path command displays additional fields when showing the forwarding path from a source interface to a destination interface in a Virtual Chassis Fabric (VCF), including details of multiple possible next hops. The vc-path command display for a forwarding path in a Virtual Chassis remains unchanged.

    [See show virtual-chassis vc-path.]

  • Gigabit interface speeds (QFX5100 switches)—Starting with Junos OS Release 14.1X53-D43, QFX5100 switches correctly interpret and display the interface speed as 1000mbps (1 Gbps) for ge- interfaces on 1-Gigabit Ethernet SFP ports. In prior releases from Junos OS Release 13.2X52-D20 up until 14.1X53-D43, the system incorrectly interprets and displays the speed of these interfaces as 10 Gbps. [See show interfaces ge.]

Open vSwitch Database (OVSDB)

  • Automatic configuration of trunk interfaces that handle untagged packets in OVSDB-managed VXLANs (QFX5100, QFX5100VC)—In previous Junos OS releases, if you specified a VLAN ID of 0 for a logical switch port in VMware NSX Manager or in the NSX API, the QFX5100 switch automatically configured an access interface to handle untagged packets in the associated Open vSwitch Database (OVSDB)–managed Virtual Extensible LAN (VXLAN). Starting with 14.1X53-D26, specifying a VLAN ID of 0 in a logical switch port configuration causes the QFX5100 switch to automatically configure a trunk port. To enable the trunk port to handle untagged packets, the QFX5100 switch also configures a native VLAN with an ID of 4094. Upon receipt of an untagged packet, the trunk interface adds a VLAN tag of 4094 to the packet and removes the tag as the packet exits the interface, thereby rendering the packet as untagged again.

    This change supports the division of an OVSDB-managed physical interface into multiple logical interfaces, some of which are associated with VXLANs that have untagged packets and some of which are associated with VXLANs that have tagged packets.


  • Change in value for a QFabric SNMP object—The jnxFabricDeviceEntryName object now displays the alias of the device and the jnxFabricDeviceEntryDescription object contains the serial number only.

Software Upgrade

  • A controlled version of Junos OS is introduced for the QFX Series in Junos OS Release 14.1X53-D15. The controlled version of Junos OS is required to enable Media Access Control security (MACsec) on a switch. The controlled version of a Junos OS release contains all features and functionality available in the standard version of the Junos OS release while also supporting MACsec. The controlled version of Junos OS is not, by default, shipped on any QFX Series switch. You can download the controlled version of Junos OS from the Software Download Center, provided that you are located in a geography where you are allowed to download the controlled version of Junos OS. If you are unsure of which version of Junos OS is running on your switch, enter the show version command. If the “JUNOS Crypto Software Suite” description appears in the output, you are running the controlled version of Junos OS.

    The controlled version of Junos OS contains encryption and is, therefore, not available to customers in all geographies. The export and re-export of the controlled version of Junos OS is strictly controlled under United States export laws. The export, import, and use of the controlled version of Junos OS is also subject to controls imposed under the laws of other countries.

    If you have questions about acquiring the controlled version of Junos OS in your country, contact the Juniper Networks Trade Compliance group at

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).

    [See fabric-tree-root.]

Modified: 2017-11-29