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Changes in Default 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 15.1R7 for the ACX Series Universal Metro Routers.

General Routing

  • Routing commands in 64-bit mode enabled by default—Starting in Junos OS Release 15.1F3 and later, routing commands in 64-bit mode are enabled by default on systems that support that mode and that have at least 16 GB of RAM.

Interfaces and Chassis

  • Connectivity fault management MEPs on Layer 2 circuits and Layer 2 VPNs—On interfaces configured on ACX Series routers, you no longer need to configure the no-control-word statement at either the [edit protocols l2circuit neighbor neighbor-id interface interface-name] or the [edit routing-instances routing-instance-name protocols l2vpn] hierarchy level for Layer 2 circuits and Layer 2 VPNs over which you are running CFM maintenance association end points (MEPs). This configuration is not needed because ACX Series routers support the control word for CFM MEPs. The control word is enabled by default.

  • In the output of the show interfaces command under the MAC Statistics section, any packet whose size exceeds the configured MTU size is considered as an oversized frame and the value displayed in the Oversized frames field is incremented. The value displayed in the Jabber frames field is incremented when a bad CRC frame size is between 1518 bytes and the configured MTU size.

  • Support for chained composite next hop in Layer 3 VPNs—Next-hop chaining (also known as chained composite next hop) is a composition function that concatenates the partial rewrite strings associated with individual next hops to form a larger rewrite string that is added to a packet. To configure the router to accept up to one million Layer 3 VPN route updates with unique inner VPN labels, include the l3vpn statement at the [edit routing-options forwarding-table chained-composite-next-hop ingress] hierarchy level. The l3vpn statement is disabled by default.


  • Support for status deprecated statement in YANG modules (ACX Series)—Starting with Junos OS Release 15.1R5, Juniper Networks YANG modules include the status deprecated statement to indicate configuration statements, commands, and options that are deprecated.