Junos OS Release Notes for PTX Series

What's New

• What’s New in Release 20.2R3

• What’s New in Release 20.2R2

• What’s New in Release 20.2R1

What’s New in Release 20.2R3

There are no new features or enhancements to existing features for PTX Series routers in Junos OS Release 20.2R3.

What’s New in Release 20.2R2

There are no new features or enhancements to existing features for PTX Series routers in Junos OS Release 20.2R2.

What’s New in Release 20.2R1

High Availability (HA) and Resiliency

• Support for failover configuration synchronization for the ephemeral database (EX Series, MX Series, MX Series Virtual Chassis, PTX Series, and QFX Series)—Starting in Junos OS Release 20.2R1, when you configure the commit synchronize statement at the [edit system] hierarchy level in the static configuration database of an MX Series Virtual Chassis or dual Routing Engine device, the backup Routing Engine will synchronize both the static and ephemeral configuration databases when it synchronizes its configuration with the master Routing Engine. This happens, for example, when a backup Routing Engine is newly inserted, comes back online, or changes roles. On a dual Routing Engine system, the backup Routing Engine synchronizes both configuration databases with the master Routing Engine. In an MX Series Virtual Chassis, the master Routing Engine on the protocol backup synchronizes both configuration databases with the master Routing Engine on the protocol master.

  [See Understanding the Ephemeral Configuration Database.]

• Unsupported hardware for unified ISSU (MX240, MX480, MX960, MX10003, and PTX3000)—The following cards do not support unified ISSU upgrading to Junos OS Release 20.2R1:

  • MPC7E-MRATE

  • MPC8E with MRATE MIC

  • MPC9E with MRATE MIC

  • MPC10E-10C-MRATE

  • MPC10E-15C-MRATE

  • PTX5000 with 24-Port 10-Gigabit Ethernet, 40-Gigabit Ethernet PIC with QSFP+ or 15-Port 10-Gigabit, 40-Gigabit Ethernet, 100-Gigabit Ethernet PIC with QSFP28

  • MX10003 with QSFP28 Ethernet TIC

Interfaces and Chassis

• Support for 1-Gbps speed on QFX10000-60S-6Q line card (PTX10008 and PTX10016)—In Junos OS Release 20.2R1 and later, the QFX10000-60S-6Q line card supports 1-Gbps speed on its ports (0 to 59). The QFX10000-60S-6Q line card contains 60 SFP+ ports that support 10 Gbps, two dual-speed QSFP28 ports that support either 40 Gbps or 100 Gbps, and four QSFP+ ports that support 40 Gbps. You can individually configure ports 0 to 59 for 10-Gbps or 1-Gbps port speed. Use the set chassis fpc fpc-slot-number pic pic-number port port-number speed 1G command to change the mode of a port from 10 Gbps to 1 Gbps. The transceivers supported for 1 Gbps are QFX-SFP-1GE-LX, QFX-SFP-1GE-SX, and QFX-SFP-1GE-T.

  By default, the QFX1000-60S-6Q line card (ports 0 to 59) operates at 10-Gbps speed.

  [See QFX10000 Line Cards for details on the combination of modes supported on the ports.]

Juniper Extension Toolkit (JET)

• RIB service APIs support dynamic next-hop interface binding (MX Series, PTX Series, and vMX)—Starting in Junos OS Release 20.2R1, programmed RIB routes react to Up, Down, Add, and Delete events for direct next-hop interfaces. When all direct next-hop interfaces are unusable, the route becomes inactive. This prevents traffic from being dropped and keeps inactive routes from being propagated through the network.

  This feature applies to all routes programmed using the rib_service JET API where an interface is configured as a direct next hop, including interfaces that are part of a flexible tunnel. It also applies to tunnels configured with the flexible_tunnel_service JET API.

  To disable this feature, use edit routing-options programmable-rpd rib-service dynamic-next-hop-interface disable.

  [See rib-service (programmable-rpd), Juniper Extension Toolkit Developer Guide, and Juniper Engineering Network website.]

• Python 3 support for JET (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 20.2R1, Junos OS can use Python 3 to execute JET scripts. To enable unsigned JET Python applications that support Python 3 to run on devices running Junos OS, use the set system scripts language python3 command.

  [See language (Scripts), Develop Off-Device JET Applications, and Develop On-Device JET Applications.]

Junos Telemetry Interface

• Network instance (policy) statistics and OpenConfig configuration enhancements on JTI (ACX1100, ACX2100, ACX5448, ACX6360, EX4300, MX240, MX480, MX960, MX10003, PTX10008, PTX10016, QFX5110, and QFX10002)—Junos OS Release 20.2R1 provides enhancements to support the OpenConfig data models openconfig-local-routing.yang and openconfig-network-instance.yang.

  [See Mapping OpenConfig Routing Policy Commands to Junos Configuration and Mapping OpenConfig Network Instance Commands to Junos Operation.]

• ON-CHANGE BGP peer information statistics support for JTI (MX960, MX2008, MX2010, MX2020, PTX1000, PTX5000, PTX10000, QFX5100, and QFX5200)—Junos OS Release 20.2R1 provides BGP peer sensor support using Junos telemetry interface (JTI) and remote procedure call (gRPC) services or gRPC Network Management Interface (gNMI) services. ON_CHANGE statistics are sent to an outside collector.

  The following resource paths are supported:

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/active (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/received (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/sent (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/rejected (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/admin-state (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/established-transitions (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/last-established (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/messages/received/notification (stream)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/messages/received/update (stream)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/messages/sent/notification (stream)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/messages/sent/update (stream)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/session-state (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/supported-capabilities (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/transport/state/local-address (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/transport/state/remote-address (ON_CHANGE)

  • /network-instances/network-instance/protocols/protocol/bgp/transport/state/remote-port (ON_CHANGE)

  [See Guidelines for gRPC and gNMI Sensors (Junos Telemetry Interface).]

• Telemetry support for LDP and MLDP traffic statistics (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, the following LDP and multipoint LDP native sensors are added for the Junos telemetry interface:

  • /junos/services/ldp/label-switched-path/ingress/usage/

  • /junos/services/ldp/label-switched-path/transit/usage/

  • /junos/services/ldp/p2mp/interface/receive/usage/

  • /junos/services/ldp/p2mp/interface/transmit/usage/

  • /junos/services/ldp/p2mp/label-switched-path/usage/

  You must enable telemetry streaming with the sensor-based-stats option at the [edit protocols ldp traffic-statistics] hierarchy level.

  The show ldp traffic-statistics command is enhanced to display upstream LDP traffic statistics and to display multipoint LDP traffic statistics per interface.

  On PTX Series routers, this feature is not supported for the following variants:

  • PTX3000 and PTX5000 with the RE-DUO-C2600-16G Routing Engine

  • PTX10003

  • PTX10008 with the PTX10K-LC1201-36CD line card

  • FPC2 line cards do not support ingress multipoint LDP statistics.

  [See sensor (Junos Telemetry Interface).]

• CPU statistics support on JTI (MX960, MX2010, MX2020, PTX1000, PTX5000, PTX10000, QFX5100, and QFX5200)—Junos OS Release 20.2R1 supports streaming various CPU statistics and process parameters using remote procedure call (gRPC) or gRPC Network Management Interface (gNMI) services and Junos telemetry interface (JTI). You can stream CPU usage per process (statistics are similar to output from the show system process detail operational mode command), as well as CPU usage per Routing Engine core.

  This feature supports the private data model openconfig-procmon.yang.

  To stream statistics to an outside collector, include the following resource paths in a gRPC or gNMI subscription:

  • Individual process level information (resource path /system/processes/process)

  • Individual Routing Engine core information (resource path /components/component/cpu/)

  [See Guidelines for gRPC and gNMI Sensors (Junos Telemetry Interface).]

• Packet Forwarding Engine sensor support with INITIAL_SYNC on JTI (MX960, MX2008, MX2010, MX2020, PTX1000, PTX5000, PTX10000 line of routers, QFX5100, and QFX5200)—Starting in Junos OS Release 20.2R1, you can use Junos telemetry interface (JTI) and gRPC Network Management Interface (gNMI) services to export Packet Forwarding Engine statistics from devices to an outside collector using gNMI submode INITIAL_SYNC. When an external collector sends a subscription request for a sensor with INITIAL_SYNC (gnmi-submode 2), the host sends all supported target leaves (fields) under that resource path at least once to the collector with the current value. This is valuable because:

  • The collector has a complete view of the current state of every field on the device for that sensor path.

  • Event-driven data (ON_CHANGE) is received by the collector at least once before the next event is seen. In this way, the collector is aware of the data state before the next event happens.

  • Packet Forwarding Engine sensors that contain zero counter values (zero-suppressed) that normally do not show up in streamed data are sent, ensuring that all fields from each line card (also referred to as source) are known to the collector.

  Note

  ON_CHANGE data is not available for native (UDP) Packet Forwarding Engine sensors.

  INITIAL_SYNC submode requires that at least one copy to be sent to the collector; however, sending more than one is acceptable.

  INITIAL_SYNC submode is supported for the following sensors:

  • Sensor for CPU (ukernel) memory (resource path /junos/system/linecard/cpu/memory/)

  • Sensor for firewall filter statistics (resource path /junos/system/linecard/firewall/)

  • Sensor for physical interface traffic (resource path /junos/system/linecard/interface/)

  • Sensor for logical interface traffic (resource path /junos/system/linecard/interface/logical/usage/)

  • Sensor for physical interface queue traffic (resource path /junos/system/linecard/interface/

queue/)

  • Sensor for physical interface traffic except queue statistics (resource path /junos/system/linecard/interface/traffic/)

  • Sensor for NPU memory (resource path /junos/system/linecard/npu/memory/)

  • Sensor for NPU utilization (resource path /junos/system/linecard/npu/utilization/)

  • Sensor for packet statistics (resource path /junos/system/linecard/packet/usage/)

  • Sensor for software-polled queue-monitoring statistics (resource path /junos/system/linecard/qmon-sw/)

  [See Understanding OpenConfig and gRPC and gNMI on Junos Telemetry Interface and Guidelines for gRPC and gNMI Sensors (Junos Telemetry Interface).]

MPLS

• Support for MPLS ping and traceroute for segment routing (ACX Series, MX Series, and PTX Series)—Starting in Junos OS Release 20.2R1, we extend the MPLS ping and traceroute support for all types segment routing--traffic engineering (SR-TE) tunnels, including static segment routing tunnels, BGP-SR-TE tunnels, and PCEP tunnels.

  We also support the following features:

  • FEC validation support, as defined in RFC 8287, for paths consisting of IGP segments. Target FEC stack contains single or multiple segment ID sub-TLVs. This involves validating IPv4 IGP-Prefix Segment and IGP-Adjacency Segment ID FEC-stack TLVs.

  • ECMP traceroute support for all types of SR-TE paths.

  We do not support the following:

  • Ping and traceroute for SR-TE tunnel for non-enhanced-ip mode.

  • OAM for IPv6 prefix.

  • BFD

  [See traceroute mpls segment-routing spring-te and ping mpls segment routing spring-te.]

Network Management and Monitoring

• SNMP support for multicast LDP MIB objects (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, Junos OS SNMP extends support for the following multicast LDP MIB tables and objects:

  • mplsMldpInterfaceStatsTable

  • mplsMldpFecUpstreamSessPackets

  • mplsMldpFecUpstreamSessBytes

  • mplsMldpFecUpstreamSessDiscontinuityTime

  The multicast LDP standard MIB builds on the objects and tables that are defined in RFC3815, which only supports LDP point-to-point label-switched paths (LSPs). This multicast LDP MIB provides support for managing multicast LDP point-to-multipoint (P2MP) and multipoint-to-multipoint (MP2MP) LSPs.

  [See Standard SNMP MIBs Supported by Junos OS and SNMP MIB Explorer.]

• Python 3 support for YANG scripts (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 20.2R1, Junos OS uses Python 3 to execute YANG action and translation scripts that are written in Python. Junos OS does not support using Python 2.7 to execute YANG Python scripts as of this release.

  [See Understanding Python Automation Scripts for Devices Running Junos OS.]

• NETCONF sessions over outbound HTTPS (EX Series, MX Series, PTX1000, PTX3000, PTX5000, PTX10001, PTX10002, PTX10008, PTX10016, QFX Series, SRX1500, SRX4100, SRX4200, SRX4600, SRX5400, SRX5600, SRX5800, and vSRX)—Starting in Junos OS Release 20.2R1, the Junos OS with upgraded FreeBSD software image includes a Juniper Extension Toolkit (JET) application that supports establishing a NETCONF session using outbound HTTPS. The JET application establishes a persistent HTTPS connection with a gRPC server over a TLS-encrypted gRPC session and authenticates the NETCONF client using an X.509 digital certificate. A NETCONF session over outbound HTTPS enables you to remotely manage devices that might not be accessible through other protocols, for example, if the device is behind a firewall.

  [See NETCONF Sessions over Outbound HTTPS.]

• Enhanced on-box monitoring support on the control plane (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, you can configure traceoptions to track all events related to system-level and process-level memory monitoring. You can also view the history of the actions taken for system-level and process-level memory monitoring by using the show system monitor memory actions command.

Routing Policy and Firewall Filters

• Support for additional route filter qualifiers in a policy statement (PTX1000 and PTX10000)—Starting in Junos OS Release 20.2R1, the following list-level qualifiers are supported: exact, longer, orlonger, prefix-length-range, and upto.

  You can use route filter lists to group individual route filters created at the [edit policy-options] hierarchy level. Each item in a list consists of a complete route filter statement, including a destination prefix, a match type, and an optional action. Reuse the list in different policies, adding whatever qualifiers you need, instead of re-creating a different one for every use case.

  [See Understanding Route Filters for Use in Routing Policy Match Conditions.]

Routing Protocols

• TI-LFA SRLG protection for IS-IS (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, you can configure Shared Risk Link Group (SRLG) protection in topology-independent loop free alternate (TI-LFA) networks. IS-IS computes the fast reroute path that is aligned with the post-convergence path and excludes the SRLG of the protected link. All local and remote links that share any SRLG with the protecting link are excluded. The point of local repair (PLR) sets up the label stack for the fast reroute path with a different outgoing interface.

  To enable TI-LFA SRLG protection with segment routing for IS-IS, include the srlg-protection statement at the [edit protocols isis interface name level number post-convergence-lfa] hierarchy level.

  [See Understanding Topology-Independent Loop-Free Alternate with Segment Routing for IS-IS.]

• Support for BGP-LU over SR-TE for color-based mapping of VPN Services (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, we are extending support to BGP labeled unicast service for color-based mapping of VPN services over Segment Routing-Traffic Engineering (SR-TE). This enables you to advertise BGP-LU IPv6 and IPv4 prefixes with an IPv6 next-hop address in IPv6-only networks where routers do not have any IPv4 addresses configured. With this feature, BGP-LU can now resolve IPv4 and IPv6 routes over the SR-TE core. BGP-LU constructs a colored protocol next hop, which is resolved on a colored SR-TE tunnel in the inetcolor.0 or inet6color.0 table. Currently, we support BGP IPv6 LU over SR-TE with IS-IS underlay.

  [See Understanding Static Segment Routing LSP in MPLS Networks.]

• Support for BGP-SR-TE rearchitecture (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, Junos OS provides support for controller-based BGP segment routing--traffic engineering (SR-TE) routes to be installed as source packet routing traffic-engineered (SPRING-TE) routes. BGP installs the SR-TE policy in the routing tables bgp.inetcolor.0 and bgp.inet6color.0, and these routes are subsequently installed in the routing tables inetcolor.0 or inet6color.0 by SPRING-TE.

  In releases before Junos OS Release 20.2R1, controller-based BGP SR-TE routes are installed as BGP routes in the routing table. To maintain consistency and for easy maintenance, all SR-TE based routes appear as SPRING-TE routes irrespective of the source.

  You need to enable source-packet-routing at the [edit protocols] hierarchy level to see the routes installed in inetcolor.0 or inet6color.0. A new option detail is introduced under traceoptions (Protocols Spring-TE) to trace the detailed information.

  [See Segment Routing Traffic Engineering at BGP Ingress Peer Overview.]

System Logging

• Support to track the maximum number of routing and forwarding (RIB/FIB) routes and VRFs (MX Series and PTX Series)—Starting in Junos OS Release 20.2R1, you can track and display the high-water mark data of routing and forwarding (RIB/FIB) table routes and VRFs in a system (RPD) using the show route summary CLI command. High-water mark refers to the maximum number of routing and forwarding (RIB/FIB) table routes and VRFs that were present in the RPD system. The high-water mark data can also be viewed in the syslog at the LOG_NOTICE level.

  You can configure the interval of the high-water mark data using the highwatermark-log-interval CLI configuration statement at the [edit routing-options] hierarchy level. The minimum time gap at which the high-water mark data logged in the syslog is 30 seconds. You can configure the value for highwatermark-log-interval CLI configuration statement between 5 and 1200 seconds.

  [See routing-options and show route summary.]

What's Changed

• What's Changed in Release 20.2R3

• What's Changed in Release 20.2R2

What's Changed in Release 20.2R3

Junos OS XML API and Scripting

• Refreshing scripts from an HTTPS server requires a certificate (ACX Series, EX Series, MX Series, PTX Series, QFX Series, SRX Series, vMX, and vSRX)—When you refresh a local commit, event, op, SNMP, or Juniper Extension Toolkit (JET) script from an HTTPS server, you must specify the certificate (Root CA or self-signed) that the device uses to validate the server's certificate, thus ensuring that the server is authentic. In earlier releases, when you refresh scripts from an HTTPS server, the device does not perform certificate validation.

  When you refresh a script using the request system scripts refresh-from operational mode command, include the cert-file option and specify the certificate path. Before you refresh a script using the set refresh or set refresh-from configuration mode command, first configure the cert-file statement under the hierarchy level where you configure the script. The certificate must be in Privacy-Enhanced Mail (PEM) format.

  [See request system scripts refresh-from and cert-file.]

• The jcs:invoke() function supports suppression of root login and logout events in system log files for SLAX commit scripts (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—The jcs:invoke() extension function supports the no-login-logout parameter in SLAX commit scripts. If you include the parameter, the function does not generate and log UI_LOGIN_EVENT and UI_LOGOUT_EVENT messages when the script logs in as root to execute the specified RPC. If you omit the parameter, the function behaves as in earlier releases in which the root UI_LOGIN_EVENT and UI_LOGOUT_EVENT messages are included in system log files.

  [See invoke() Function (SLAX and XSLT).]

• The jcs:invoke() function supports suppression of root login and logout events in system log files for SLAX event scripts (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—The jcs:invoke() extension function supports the no-login-logout parameter in SLAX event scripts. If you include the parameter, the function does not generate and log UI_LOGIN_EVENT and UI_LOGOUT_EVENT messages when the script logs in as root to execute the specified RPC. If you omit the parameter, the function behaves as in earlier releases in which the root UI_LOGIN_EVENT and UI_LOGOUT_EVENT messages are included in system log files.

  [See invoke() Function (SLAX and XSLT).]

Network Management and Monitoring

• Changes to <commit> RPC responses in RFC-compliant NETCONF sessions (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—When you configure the rfc-compliant statement at the [edit system services netconf] hierarchy level, the NETCONF server's response for <commit> operations includes the following changes:

  • If a successful <commit> operation returns a response with one or more warnings, the warnings are redirected to the system log file, in addition to being omitted from the response.

  • The NETCONF server response emits the <source-daemon> element as a child of the <error-info> element instead of the <rpc-error> element.

  • If you also configure the flatten-commit-results statement at the [edit system services netconf] hierarchy level, the NETCONF server suppresses any <commit-results> XML subtree in the response and emits only an <ok> or <rpc-error> element.

  [See Configuring RFC-Compliant NETCONF Sessions.]

• PTX10003 routers do not support set chassis fpc fpc-slot power on—The PTX10003-80C and PTX10003-160C routers do not support the set chassis fpc fpc-slot power on command. Executing this command on an FPC which is offline could cause unintended reboots of the router.

User Interface and Configuration

• Verbose format option to export JSON configuration data (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—The Junos OS CLI exposes the verbose statement at the [edit system export-format json] hierarchy level. We changed the default format to export configuration data in JSON from verbose to ietf starting in Junos OS Release 16.1R1. You can explicitly specify the default export format for JSON configuration data by configuring the appropriate statement at the [edit system export-format json] hierarchy level. Although the verbose statement is exposed in the Junos OS CLI as of the current release, you can configure this statement starting in Junos OS Release 16.1R1.

  [See export-format.]

What's Changed in Release 20.2R2

General Routing

• Trigger alarms when a PTX10008 or PTX10016 router has a mix of AC and DC power supplies—If you insert a mix of AC and DC power supply units (PSUs) into a PTX10008 or PTX10016 router, Junos OS raises an alarm to indicate that there is a mix of AC and DC power supplies in the router. To fix this alarm, you need to ensure that the router has the same type of power supplies.

  [See Understanding Chassis Alarms.]

• Control plane DDoS protection packet type option for ARP traffic (PTX Series and QFX Series)—Starting in this release, the arp-snoop packet type option in the edit system ddos-protection protocols arp protocol group is renamed simply arp. This packet type option enables you to change default control plane DDoS protection policer parameters for ARP traffic. After this change, the edit system ddos-protection protocols arp protocol group includes aggregate, arp, and unclassified packet type options.

  [See protocols (DDoS) (PTX Series and QFX Series).]

• PTX10001-36MR, PTX10008, and PTX10016 routers support a maximum of two drop profile pairs (PTX Series)—Pair one drop probability must be less than or equal to 25%. Point two drop probability value must be greater than point one drop probability value. Pair two fill level must be greater than or equal to 1.2 times the pair one fill level.

  [See CoS Features and Limitations on PTX Series Routers.]

• IPv6 address in the prefix TIEs displayed correctly—The IPv6 address in the prefix TIEs are displayed correctly in the show rift tie output.

MPLS

• Change in auto bandwidth adjustment (PTX5000)—If auto bandwidth adjustment fails because of bandwidth unavailable error, the router tries to bring up the LSP with the same bandwidth during the subsequent reoptimization. In earlier releases, when the auto bandwidth adjustment fails, the current bandwidth is reset to the bandwidth that was already active.

  [See rsvp-error-hold-time.]

Routing Protocols

• Advertising 32 secondary loopback addresses to traffic engineering database as prefixes (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—We've made changes to export multiple loopback addresses to the lsdist.0 and lsdist.1 routing tables as prefixes. This eliminates the issue of advertising secondary loopback addresses as router IDs instead of prefixes. In earlier releases, multiple secondary loopback addresses in the traffic engineering database were added to the lsdist.0 and lsdist.1 routing tables as part of node characteristics and advertised them as the router ID.

Known Limitations

• General Routing

• MPLS

• Routing Protocols

General Routing

• On the PTX10008 or PTX10016 routers, the GRES takes more than 3 minutes to complete when shutdown is initiated by the internal vmhost init 0 command. PR1312065

• The filter-based GRE encapsulation does not work in the egress direction when the filter attachment interface and the interface to reach the next hop are the same. PR1465837

• During reconfigurations and link events at the physical interface level, the pe.ipw.misc_int.status:iq_disabled error message can be seen. This does not impact traffic. PR1476553

• The sflow record command shows incorrect output interface for the egress sampling during the incoming MPLS|IPv4 and outgoing IPv4 with ECMP. PR1478012

• The PTX10000 routers include the incoming MPLS label stack length also in the jvision counters when acting as the PE device egress counter. PR1482408

• On the PTX1000 routers, the following error message is observed when the sampling MPLS+IPv4/IPv6 traffic is forwarded over the IP-IP tunnel: dlu.ucode.jflow_not_routable pechip. PR1485770

• The following error messages are seen after configuring set chassis maximum-ecmp 64: JPRDS_NH:jprds_nh_alloc(),990: JNH[3] failed to grab new region for EGRESS. PR1490813

• The show dynamic-tunnels database statistics <dest> command must be structured so that the statistics are fetched deterministically for the IPv4 and IPv6 based tunnels. PR1488715

MPLS

• Traffic outage during FRR is observed with ingress node logs data errors. PR1430361

Routing Protocols

• Router receives and discards traffic for three-and-a-half minutes after bootup when IGP overload is configured. PR1495435

Open Issues

• General Routing

• Infrastructure

• Interfaces and Chassis

• Layer 2 Ethernet Services

• MPLS

• Platform and Infrastructure

• Routing Protocols

General Routing

• When CFP2-DCO-T-WDM-1 is plugged in to a PTX Series PIC, after FPC restarts, the carrier frequency offset TCA is raised even when TCA is not enabled. PR1301471

• On 30-port MACsec-enabled line card (LC1101-M-30C, LC1101-M-30Q, and LC1101-M-96X) of the PTX10008 chassis, when the exclude-protocol lacp statement configured at the [edit security macsec connectivity-association connectivity-association-name] hierarchy level is deleted or deactivated, the LACP protocol's Mux State shown under the output of CLI command show lacp interface, might remain as attached or detached and might not change to distributing state. PR1331412

• The PTX Series platform drops the wireless access point (WAP) heartbeat packets; as a result, the WAP cannot work. PR1352805

• Due to transient hardware condition, single-bit error (SBE) events are corrected and have no operational impact. Reporting of those events had been disabled to prevent alarms and possibly unnecessary hardware replacements. This change applies to all platforms using Hybrid Memory Controller (HMC). PR1384435

• On the PTX10000 Series platform, the CPU overuse on priority-based flow control might be observed if the adaptive feature is enabled to load-balance for an aggregated Ethernet interface. PR1399369

• On the PTX3000 routers, the firewall counter for lo0 does not increment. PR1420560

• The em2 interface configuration causes FPC to crash during initialization and FPC does not come online. After deleting the em2 configuration and restarting the router, FPC comes online. PR1429212

• When the firewall filter has Port-Mirror as an action along with discard action, the mirrored packet will have two L2 headers. The first L2 header will be the original L2 header and the second L2 header will be egress interface L2 header. This causes packet corruption and discard. PR1437546

• Memory leaks are expected in this release. PR1438358

• On Junos OS platforms with next generation Routing Engine installed, the process vehostd may crash without the core file and automatic restart of vehostd may fail. Vehostd is a mib2d MIB II process for managing the lifecycle of system-critical Junos OS VMs in the system. If the process vehostd gets in a crash state, it will impact the management of Junos OS VMs. PR1448413

• With auto-channelization support, an optic speed mismatch connection might cause the auto-channelization to get into an infinite loop trying to match a proper speed. In this case, due to some memory leaks, the resources get exhausted, resulting in system crash. The traffic gets disrupted when the system dcpfe restarts. PR1484336

• The Layer 2 VPN with asynchronous-notification might flap when the link goes up between the PE device and CE device. After Layer 2 VPN flaps, the interfaces with asynchronous-notification might show - Inf dBm laser output power even if the Layer 2 VPN is in the up status. PR1486181

• Traceroute on IPoIP tunnel might not work if decap and encap routes are present in two different routing instances. PR1488379

• On PTX1000 and PTX10001 routers, the port mirror will not work when the port-mirroring is configured with the firewall filter. PR1491789

• Dynamic-tunnels traceoptions might cause scheduler slips with single underlay route bounce for large scale. PR1493236

• On a Junos OS platform, the output of Aggregate Ethernet (AE) interface statistic does not include its member links' statistics. PR1505596

• Add Python 3.x modules that are missing from the library. PR1508626

• MPLS sensor does not receive Junos Telemetry Interface data on the server. PR1514959

• When you continuously run the sync (using the show interfaces aex extensive command) and the async (using SNMP polling) queries in parallel on aggregated Ethernet interfaces, you might notice spikes in aggregated Ethernet interface framing errors counter in between correct values. PR1539537

• On PTX Junos OS platforms, there might be traffic drop when default EXP classifier maps traffic to FC with no schedulers.PR1554266

• On PTX10002-60C platform, after disabling the standalone and non-channelized port (e.g. port 6, 16,26,36,46,56), then another port on that port group will aslo be disabled. For example, disable et-0/0/36, port et-0/0/30 is going to down as well. This issue is only exposed when using DAC cables. PR1568294

• On PTX platforms, when Inline Jflow is configured and high sampling rate (more than 4000 per second) is set, high CPU utilization might be observed and this might result in relevant impacts on traffic analysis and billing. PR1569229

• LLDP out-of-bounds read vulnerability in l2cpd. PR1569312

• On PTX5000 with '15x100GE/15x40GE/60x10GE QSFP28' PIC on FPC type 3, when the port is configured in 4x10G mode (using QSFP+) and one of the 10G channels detected a clear of Rx LOS (Loss Of Signal), the traffic might be dropped on all the four 10G channels. PR1578511

• On PTX Series routers, the traffic from TACACS port 49 might not be classified into a proper DDoS queue. When the issue happens, it might cause the unclassified traffic to get dropped when the CPU utilization is very high. PR1578579

• On PTX platforms, BFD sessions might flap during traffic spikes. PR1578599

• On PTX platforms with vlan-ccc configured, if it acts as a provider edge device and forwards the IS-IS packet between CEs over the Layer 2 circuit tunnel, the IS-IS packet might be corrupted. In this case, the IS-IS adjacency might not be formed. PR1580047

• The packets might be dropped by Packet Forwarding Engine of PTX5000 after changing the queue of IEEE-802.1ad classifier on FPC-PTX-P1-A or FPC2-PTX-P1A.PR1584042

• Memory corruption of a binary from /usr/bin/ or /usr/sbin/ directory can occur if such binary is invoked when a recovery snapshot creation is in progress. The exact symptoms will be different depending on the exact binary and JUNOS version - some programs will show an error, and some programs will crash every time it is executed. Such memory corruption will be persistent until the affected routing engine is restarted. PR1563647

Infrastructure

• Memory corruption of a binary from /usr/bin/ or /usr/sbin/ directory can occur if such binary is invoked when a recovery snapshot creation is in progress. The exact symptoms will be different depending on the exact binary and JUNOS version - some programs will show an error, and some programs will crash every time it is executed. Such memory corruption will be persistent until the affected routing engine is restarted. PR1563647

Interfaces and Chassis

• Upgrading Junos OS Release 14.2R5 and later maintenance releases and Junos OS Release 16.1 and later mainline releases with a CFM configuration might cause the cfmd process to crash after the upgrade. This is because of the presence of an old version of /var/db/cfm.db. PR1281073

Layer 2 Ethernet Services

• It is observed rarely that issuing request system zeroize did not trigger zero-touch provisioning. A workaround is to re-initiate the ZTP. PR1529246

MPLS

• At high scale, LSP setup rate will be relatively slower in IP-in-IP networks. PR1457992

• On all Junos OS platforms, the rpd process on the transit node might crash when MPLS traceroute on the ingress node is performed. PR1573517

Platform and Infrastructure

• On Junos OS, upon receipt of specific sequences of genuine packets destined to the device the kernel will crash and restart (vmcore). PR1557881

Routing Protocols

• With an aggregated Ethernet interface with BFD configured, the aggregated Ethernet interface and BFD session remain down after the interface is disabled or enabled. PR1354409

• The show dynamic-tunnels database command does not show the current value of traffic statistics. It shows the cached value of traffic statistics, which might not be equal to the current value. PR1445705

Resolved Issues

• Resolved Issues: 20.2R3

• Resolved Issues: 20.2R2

• Resolved Issues: 20.2R1

Resolved Issues: 20.2R3

General Routing

• Flexible PIC concentrator reboot might be observed in the events of J-Lock hog for more than 5 seconds. PR1439929

• On PTX10016 routers, if aggregated Ethernet member or interface flow control is in disabled state, then it does not enable its own. PR1478715

• SNMP index in the Packet Forwarding Engine reports as 0. This causes the sFlow records to have either IIF (Input interface value) or OIF (Output interface value) as 0 value in sFlow record data at collector. PR1484322

• PTX10008: FPC UKERN core dump is not transferred to Routing Engine in scaled setup. PR1500418

• Error messages t6e_dfe_tuning_state:et-6/0/0 - Failed to dfe tuning count 10might be seen after links flap PR1512919

• TCP connection going through Packet Forwarding Engine might not be closed at the remote end because there is no TCP FIN segment sent out when the local device is rebooted. PR1517154

• In PTX1000, after upgrading, configured firewall filters might be applied on incorrect interfaces (CVE-2021-31382). PR1517804

• FPC crash might be observed during both deleting and reaping the configuration. PR1519868

• Packet drops might be seen with all commit events with 1G speed configured interface. PR1524614

• Multiple FRUs disconnection alarms might be displayed post the firmware upgrade. PR1529710

• PTX1000 might become unreachable with no console access after performing vmhost reboot post image upgrade. PR1530529

• The LACP member link might be down if LFM is deleted from it. PR1531235

• The chassisd memory leak might cause traffic loss. PR1537194

• The rpd memory leak might be observed on the backup Routing Engine due to the flapping of the link. PR1539601

• The error message expr_dfw_action_topo_connect_anh:1434 expr_dfw_action_topo_connect_anh:eda_anh_discard is FALSE for nh-id 568 - return is observed in PTX1000 routers.PR1540064

• The Packet Forwarding Engine might crash in an MPLS IPv6-tunneling scenario when the next hop changes. PR1540793

• Optimize PTX PE Chip EPW CRC error reporting - PE Error code: 0x2101aa. PR1542580

• The kernel crash might happen if NSR is enabled. PR1545143

• Junos OS: PTX Series: Denial of Service in packet processing due to heavy route churn when J-Flow sampling is enabled (CVE-2021-0263). PR1546143

• On the PTX10000 platforms, traffic might get dropped when the set routing-options forwarding-table no-ecmp-fast-reroute configuration is changed to 128 ECMP entries. PR1547457

• Traffic might drop silently after swapping an FPC Type 3 card with an FPC Type 1 card in the same slot on a PTX3000 router. PR1547790

• The rpd crash might be seen when BGP service route is resolved over color-only SR-TE. PR1550736

• Interface filter with source-port 0 is matching everything instead of just port 0. PR1551305

• Packet drop might happen on the aggregated Ethernet bundle which have the single child member only. PR1551736

• The LCM Peer Absent message might be seen. PR1551760

• The lcmd process might consume memory until all of the free memory available to VMHOST gets exhausted. PR1555386

• The micro BFD session might flap with DDoS policer. PR1557782

• An enhancement to enable watchdog petting log on PTX10000 Line Cards. PR1561980

• Junos OS: Upon receipt of specific packets BFD sessions might flap due to DDoS policer implementation in Packet Forwarding Engine (CVE-2021-0280). PR1564807

• Upgrading PTX1000 with unified SSDs (2x32G SSD) might result in boot loop in certain scenario. PR1571275

Forwarding and Sampling

• l2ald might crash due to next-hop issue in the EVPN-MPLS. PR1548124

Infrastructure

• Output drops in show interfaces extensive might display 0 temporarily during a race condition when SNMP query for JnxCos is also issued PR1533314

• Interface drop counters might display 0 during a race condition when VOQ statistics are also polled simultaneously. PR1537960

• Invalid statistics value might be observed when multiple mib2d/cosd requests for the same IFD arrive within 1 second. PR1541579

• The kernel crash with core file might be seen if churn happens for a flood composite next hopPR1548545

Interfaces and Chassis

• EOAM IEEE802.3ah link discovery state is Down instead of Active Send Local after deactivating interfaces on routers. PR1532979

• The traffic loss might be observed on an interface when configuring the non-related to the interface. PR1541835

• Logs are not being written in /var/log/messages on certain PTX platforms.PR1551374

MPLS

• On Junos OS, receipt of a specific LDP message might cause a Denial of Service (CVE-2021-31363). PR1552041

• MPLS-LIB memory leak might be seen in SR scenario. PR1556495

• Traffic sent over an LSP might be dropped if two consecutive PLRs along the LSP perform local repair and bypass protecting the second PLR fails. PR1566101

Multicast

• FPC might crash in a multicast scenario. PR1569957

Network Management and Monitoring

• The syslog messages might not be sent with the correct port number info. PR1545829

• The mib2d process crashes and generates a core dump on backup Routing Engine. PR1557384

Platform and Infrastructure

• In a rare occurrence, the Routing Engine kernel might crash while handling the TCP sessions if you enable GRES or NSR.PR1546615

• The BGP session replication might fail to start after the session crashes on a backup Routing Engine. PR1552603

Routing Policy and Firewall Filters

• Generate route goes to hidden state when protect core statement is enabled. PR1562867

Routing Protocols

• Traffic loss about 2-3 seconds might be seen if anycast IP is used as an abstract next-hop in BGP EPTE. PR1450366

• The rpd might crash with BGP RPKI enabled in a race condition. PR1487486

• Traffic might be silently discarded when the BGP route gets deleted, which is part of multipath. PR1514966

• ECMP load-balance might not work as expected in SR ISIS scenario on PTX platforms. PR1532390

• The rpd process generates the core file at gp_rtarget_tsi_update,bgp_rtarget_flash_rt,bgp_rtarget_flash. PR1541768

• The rpd memory leak might be seen in the BGP scenario. PR1547273

• The BGP LU session might flap with AIGP-used scenario. PR1558102

• Traffic loss might occur for stitched traffic from SR towards LDP if no-eligible-backup is configured. PR1558565

• The ppmd memory leak might cause traffic loss. PR1561850

VPNs

• The Layer 2 circuit local-switching end interface might get stuck in XX (Unknown) state upon vlan-id-list configuration change PR1528809

• The rpd might crash during a race condition under BGP multipath scenario. PR1567918

Resolved Issues: 20.2R2

General Routing

• On PTX5000 and PTX10008 routers, the output of the show filter index number counter command shows value as zero at 28-02-HOSTBOUND_NDP_DISCARD_TERM. PR1420057

• The show snmp mib walk jnxContentsDescr command output does not show the fan controllers. PR1455640

• On PTX10016 routers, after device reboot, the FPC takes a long time to come up and hence MKA session establishment is delayed. The error message Frame 08: sp = 0x48d222b8, pc = 0x10fad3bc , blaze fpc2 SCHED: Thread 59 (PFE Manager) ran for 2177 ms without yielding is observed. PR1477585

• Any change in nested groups might not be detected on commit and does not take effect. PR1484801

• Outbound SSH connection flaps or a memory leak issue is observed during the push configuration to the ephemeral database with a high rate. PR1497575

• The error message mpls_extra NULL might be seen when you add, change, or delete MPLS route. PR1502385

• An error message PFE_ERROR_FAIL_OPERATION: IFD et-1/0/8: RS credits failed to return: init=192 curr=193 chip=5 is observed. PR1502716

• ERO update by the controller for branch LSP might cause issues. PR1508412

• On PTX3000 and PTX5000 routers, unable to bring the ports up when plugging in the optic QSFP-100G-LR4-T2 (740-061409). PR1511492

• The route update might fail because of an HMC memory issue and traffic impact might be seen. PR1515092

• On PTX1000 and PTX10002-60C routers, sFlow adaptive-sampling, with rate limiter statement enabled, crosses the sampling rate 65535. PR1525589

Interfaces and Chassis

• When multiple CFM sessions are configured on a physical interface, SNMP walk of ieee8021CFMStack table fails. PR1517046

• EOAM IEEE802.3ah link discovery state is Down instead of Active Send Local after deactivating interfaces on routers. PR1532979

MPLS

• SNMP trap is observed with incorrect OID jnxSpSvcSetZoneEntered. PR1517667

Routing Protocols

• On PTX3000 and PTX5000 routers, the ppmd process generates a core file after configuring the S-BFD responder on the RE-DUO-2600. PR1477525

• The rpd process might report 100 percent CPU usage with BGP route damping enabled. PR1514635

Resolved Issues: 20.2R1

General Routing

• PTX interface stays down after the maintenance. PR1412126

• With Junos OS Release 19.4R1 on PTX10008 device along with 4x1GE feature, continuous logging in the chassisd file is observed. PR1456253

• Upgrading fails due to communication failure between the Junos VM and host OS. PR1438219

• The local-loopback test fails with the gigether options. PR1458814

• The PTX1000 or PTX10002 router might discard traffic silently after the transient SIB or FPC voltage alarms. PR1460406

• On the PTX5000 for FPC3, optics-options syslog and link-down do not work as expected. PR1461404

• The sample, syslog, or log action in the output firewall filter with packet size less than 128 might cause ASIC wedge (all packet loss). PR1462634

• On modifying TNL DST NETWORK (more specific TNL DST NETWORK), the IP-IP tunnel gets flushed but fails to get created even though a less specific matching TNL DST NETWORK exists. PR1462805

• On the PTX10000 line of routers, FPC might restart during runtime. PR1464119

• The PTX5000 SIB3 might fail to come up in the slot 0 with or without slot 8 when the Routing Engine 1 is the master. PR1471178

• The input-vlan-map or output-vlan-map might not work properly in the Layer 2 circuit local-switching scenario. PR1474876

• Sampling process might crash when the MPLS or MPLS over the UDP traffic is sampled. PR1477445

• Multicast routes add or delete events might cause adjacency and LSPs to go down. PR1479789

• FPC might crash when dealing with the invalid next hops. PR1484255

• In the StrictPriority mode, the MedH and MedL should be of separate priorities; StrcH and High become one priority. PR1490505

• The BFD sessions flap when the firewall filter in the loopback0 is changed. PR1491575

• Traffic impact might be seen when policy-multipath is configured without LDP on the Spring-TE scenario. PR1483585

• On a dual Routing Engine GRES or NSR enabled PTX10008 or PTX10016 router, a few TCP-based application sessions like BGP or LDP might flap upon Routing Engine primary-role switch. PR1503169

• The router might become nonresponsive and bring traffic down when the disk space becomes full. PR1470217

• Unable to bring the ports up when plugging the optic QSFP-100G-LR4-T2(740-061409) to PTX3000 or PTX5000. PR1511492

• PHP device has NH mis-programming for members of ECMP for SR label route used for reaching the IPV6 destinations. PR1457230

• Kernel Routing Table (KRT) queue gets stuck after the J-Flow samples a malformed packet. PR1495788

Infrastructure

• Slow response from SNMP might be observed after an upgrade to Junos OS Release 19.2R1 and later. PR1462986

Layer 2 Ethernet Services

• Member links state might be asynchronized on a connection between the PE device and the CE devices in the EVPN A/A scenario. PR1463791

MPLS

• Kernel crash and device restart might occur. PR1478806

• The BGP session might keep flapping between two directly connected BGP peers because of the wrong usage of the TCP-MSS. PR1493431

• The rpd process might crash in a rare condition under the SR-TE scenario. PR1493721

Routing Protocols

• The BGP NSR must be able to synchronize 4000 or more IPv6 sessions. PR1461436

• On the PTX3000 or PTX5000 line of routers, the ppmd process generates a core file after configuring the sbfd responder on the RE-DUO-2600. PR1477525

• The rpd process might crash with the BGP multipath and route withdraw occasionally. PR1481589

• The BGP route-target family might prevent RR from reflecting Layer 2 VPN and Layer 3 VPN routes. PR1492743

• BGP multi-path traffic might not fully load-balance for a while after adding a new path for the load sharing. PR1482209

• LSP auto-bandwidth adjust-interval change does not get detected on commit in some cases. PR1484801

Documentation Updates

Migration, Upgrade, and Downgrade Instructions

• Basic Procedure for Upgrading to Release 20.2

• Upgrade and Downgrade Support Policy for Junos OS Releases

• Upgrading a Router with Redundant Routing Engines

Basic Procedure for Upgrading to Release 20.2

When upgrading or downgrading Junos OS, use the jinstall package. For information about the contents of the jinstall package and details of the installation process, see the Installation and Upgrade Guide. Use other packages, such as the jbundle package, only when so instructed by a Juniper Networks support representative.

1. Using a Web browser, navigate to the All Junos Platforms software download URL on the Juniper Networks webpage:

   https://support.juniper.net/support/downloads/

2. Select the name of the Junos OS platform for the software that you want to download.
3. Select the release number (the number of the software version that you want to download) from the Release drop-down list to the right of the Download Software page.
4. Select the Software tab.
5. In the Install Package section of the Software tab, select the software package for the release.
6. Log in to the Juniper Networks authentication system by using the username (generally your e-mail address) and password supplied by Juniper Networks representatives.
7. Review and accept the End User License Agreement.
8. Download the software to a local host.
9. Copy the software to the routing platform or to your internal software distribution site.
10. Install the new jinstall package on the router.Note

    We recommend that you upgrade all software packages out of band using the console because in-band connections are lost during the upgrade process.

    All customers except the customers in the Eurasian Customs Union (currently composed of Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Russia) can use the following package:

    user@host> request system software add validate reboot source/junos-install-ptx-x86-64-20.2R3.9.tgz

    Customers in the Eurasian Customs Union (currently composed of Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Russia) can use the following package (limited encryption Junos OS package):

    user@host> request system software add validate reboot source/junos-install-ptx-x86-64-20.2R3.9-limited.tgz

    Replace the source with one of the following values:

    • /pathname—For a software package that is installed from a local directory on the router.

    • For software packages that are downloaded and installed from a remote location:

      • ftp://hostname/pathname

      • http://hostname/pathname

      • scp://hostname/pathname

    The validate option validates the software package against the current configuration as a prerequisite to adding the software package to ensure that the router reboots successfully. This is the default behavior when the software package being added is a different release.

    Adding the reboot command reboots the router after the upgrade is validated and installed. When the reboot is complete, the router displays the login prompt. The loading process might take 5 to 10 minutes.

    Rebooting occurs only if the upgrade is successful.

Upgrade and Downgrade Support Policy for Junos OS Releases

We have two types of releases, EOL and EEOL:

• End of Life (EOL) releases have engineering support for twenty four months after the first general availability date and customer support for an additional six more months.

• • Extended End of Life (EEOL) releases have engineering support for thirty six months after the first general availability date and customer support for an additional six more months.

For both EOL and EEOL releases, you can upgrade to the next three subsequent releases or downgrade to the previous three releases. For example, you can upgrade from 19.2 to the next three releases – 19.3, 19.4 and 20.1 or downgrade to the previous three releases – 19.1, 18.4 and 18.3.

For EEOL releases only, you have an additional option - you can upgrade directly from one EEOL release to the next two subsequent EEOL releases, even if the target release is beyond the next three releases. Likewise, you can downgrade directly from one EEOL release to the previous two EEOL releases, even if the target release is beyond the previous three releases. For example, 19.2 is an EEOL release. Hence, you can upgrade from 19.2 to the next two EEOL releases – 19.3 and 19.4 or downgrade to the previous two EEOL releases – 19.1 and 18.4.4.

For more information about EOL and EEOL releases, see https://www.juniper.net/support/eol/junos.html.

For information about software installation and upgrade, see the Installation and Upgrade Guide.

Upgrading a Router with Redundant Routing Engines

If the router has two Routing Engines, perform a Junos OS installation on each Routing Engine separately to avoid disrupting network operation as follows:

1. Disable graceful Routing Engine switchover (GRES) on the master Routing Engine and save the configuration change to both Routing Engines.

2. Install the new Junos OS release on the backup Routing Engine while keeping the currently running software version on the master Routing Engine.

3. After making sure that the new software version is running correctly on the backup Routing Engine, switch over to the backup Routing Engine to activate the new software.

4. Install the new software on the original master Routing Engine that is now active as the backup Routing Engine.

For the detailed procedure, see the Installation and Upgrade Guide.