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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 in Junos OS Release 17.1R2 for the PTX Series.

General Routing

  • ECMP next hops supported for IS-IS IPv6—When maximum-ecmp 64 option is enabled and if an IS-IS route has multiple next hops or if it is above the maximum limit, then the rpd crashes because the next hop gateway addresses are overwritten and stored in a circular buffer. Note: In the worst case (if all the next hops are IPv6), only 38 ECMP next hops are fully supported for IS-IS IPv6 instead of 64.

Interfaces and Chassis

  • Message now displayed when SIB autohealing is complete (PTX3000 and PTX5000)—In Junos OS Release 17.1R1 and later, the output of show chassis fabric errors autoheal displays a message when SIB autohealing is complete, as shown in the following example:


  • Enhancement to Junos Telemetry Interface (PTX Series)—Starting with Junos OS Release 17.1R1, Junos Telemetry Interface data streamed through gRPC no longer includes the phrase oc-path in the prefix field. For example, a physical interface sensor streaming data for interface et-0/0/0:0 now displays the following output: str_value:/interfaces/interface[name='et-0/0/0:0']/.

  • Enhancement to NPU memory sensors for Junos Telemetry Interface (PTX Series)—Starting with Junos OS Release 17.1R2, the path used to subscribe to telemetry data for network processing unit (NPU) memory and NPU memory utilization through gRPC has changed. The new path is /components/component[name="FPC<fpc-id>:NPU<npu-id>"]/

    [See Guidelines for gRPC Sensors.]


  • Representation for OSPF DR node—Up until version -10 of the BGP-LS draft, the OSPF DR node representation was ambiguous. One could represent DR node as 'AdvertisingRouterId-InterfaceIpAddress' or 'InterfaceIpAddress-1'. JUNOS used to follow 'InterfaceIpAddress-1' format. Starting with version '-11' of the BGP-LS draft, the representation for OSPF DR node must be 'AdvertisingRouterId-InterfaceIpaddress'. Junos OS now follows the latest format.

  • PPPoE subscribers do not bind over ps interfaces (MX Series)—Starting with Junos OS Release 17.1R1, the termination of single, multiple, and dual-tagged service delimited VLANs are transported over a single Ethernet CCC pseudowire using ps virtual port devices. This feature provides scaled Layer 3 service application at the pseudowire head-end termination appliance. This behavior is as an extension and evolution for ethernet pseudowire that is described in RFC 4448.

Network Management and Monitoring

  • Update to SNMP support of apply-path statement (PTX Series)—In Junos OS Release 17.1R2, SNMP implementation for the apply-path configuration statement supports only two lists:

    • apply-path "policy-options prefix-list <list-name> <*>"

      This configuration has been supported from day 1.

    • apply-path "access radius-server <*>"

      This configuration is supported as of this release.

Routing Protocols

  • Change in default behavior of router capability (PTX Series)—In Junos OS Release 15.1F7, 16.1R4, 16.1X65, and 17.1R1 and later, the router capability TLV distribution flag (S-bit), which controls IS-IS advertisements, will be reset, so that the segment-routing-capable sub-TLV is propagated throughout the IS-IS level and not advertised across IS-IS level boundaries.

Services Applications

  • Device discovery with device-initiated connection (PTX Series)—In Junos OS Release 17.1R1 and later, when you configure statements and options under the [system services ssh] hierarchy and commit the configuration, make sure that the system reaches a stable state before you commit any outbound-ssh configurations.

    You use the device discovery feature in the Devices workspace to add devices to Junos Space Network Management Platform. By default, Junos Space manages devices by initiating and maintaining a connection to the device.

    [See Device Discovery Overview.]

System Management

  • Peers option not supported in batch configuration mode— Starting in Junos OS Release 17.1R1, the peers option at the [edit system commit] hierarchy level is not supported in batch configuration mode.

User Interface and Configuration

  • Integers in configuration data in JSON format are displayed without quotation marks (PTX Series)—Starting in Junos OS Release 17.1R1, integers in Junos OS configuration data emitted in JavaScript Object Notation (JSON) format are not enclosed in quotation marks. Prior to Junos OS Release 17.1R1, integers in JSON configuration data were treated as strings and enclosed in quotation marks.

  • Changes to the show system schema module juniper-command output directory (PTX Series)—Starting in Junos OS Release 17.1, when you issue the show system schema module juniper-command operational command in the Junos OS CLI, the device places the generated output files in the current working directory, which defaults to the user’s home directory. Prior to Junos OS Release 17.1, the generated output files are placed in the /var/tmp directory.