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Junos OS Release Notes for ACX Series


These release notes accompany Junos OS Release 19.4R3 for the ACX Series. They describe new and changed features, limitations, and known and resolved problems in the hardware and software.

You can also find these release notes on the Juniper Networks Junos OS Documentation webpage, located at

What's New

Learn about new features introduced in the Junos OS main and maintenance releases for ACX Series routers.

What's New in Release 19.4R3

There are no new features or enhancements to existing features for ACX Series Junos OS Release 19.4R3.

What's New in Release 19.4R2

Dynamic Host Configuration Protocol (DHCP)

  • Support for DHCPv6-PD on EVPN IRB synchronization between multiple PE routers (ACX 5448, ACX5448-M and ACX5448-D)—Starting in Junos OS Release 19.4R2, you can use DHCPv6 prefix delegation (DHCPv6-PD) to automate the delegation of IPv6 prefixes to a requesting router on EVPN IRB. DHCPv6 prefix delegation is configured on EVPN IRB and provides IPv6 prefixes to the requesting clients, instead of the unique address. The DHCPv6-PD server acts as a provider edge (PE) router that provides the delegates through the relay (PE router) operating in the EVPN instance.

    If one PE router fails, appropriate DHCPv6-PD state is made available for the remaining PE routers participating in the DHCP-PD process for the given VLAN. This is done using automatic synchronization of DHCPv6-PD states between multiple PE routers connected to the same Ethernet Segment Identifier (ESI) through EVPN BGP messages.

  • Support for DHCP Option 82 over EVPN (ACX5448, ACX5448-M and ACX5448-D)—Starting in Junos OS Release 19.4R2, we have inserted Option 82 flags in the DHCP packets for enhanced security when the packet is sent to the server. The provider edge router that is part of the EVPN instance acts as the relay agent and inserts these flags to the DHCP packets.

    DHCPv4 and DHCPv6 relay of packets uses this process. With the introduction of EVPN IRB, the relay agent uses the IRB interface with EVPN for forwarding the requests and replies to and from the client or the server instead of using the default routing.

  • Support for persistent storage of DHCPv4 and DHCPv6 bindings over EVPN IRB (ACX5448, ACX5448-M and ACX5448-D)—Starting in Junos OS Release 19.4R2, ACX5448, ACX5448-M and ACX5448-D routers, when configured to function as a DHCP relay agent, can also be configured to preserve the DHCPv4 and DHCPv6 subscriber bindings across reboots. Existing bindings are written to a local file in /var/preserve. After reboot, the binding table is populated with the contents of the file and the router identifies each subscriber that was on the deleted interface, and resumes normal packet processing for subscribers when the interface is restored. To preserve the subscriber binding information, enable the perisistent-storage statement under the [edit system services dhcp-local-server] hierarchy.

    [See Preserving Subscriber Binding Information and DHCPv6 Relay Agent Overview.]


  • Multicast with IGMP or MLD snooping across VLANs for EVPN-MPLS (ACX5448)—Starting in Junos OS Release 19.4R2, ACX5448 routers support inter-VLAN multicast forwarding with IGMP or MLD snooping in an EVPN over MPLS network as follows:

    • Multicast sources are external to the EVPN instance in a Layer 3 Protocol Independent Multicast (PIM) domain.

    • All provider edge (PE) devices in the EVPN instance connect to a PIM gateway router in the PIM domain using Layer 3 interfaces, and send PIM join messages toward the PIM rendezvous point (RP) for their receivers that want to join a multicast group.

    • The PIM gateway router forwards traffic for the multicast group from the external sources to all PE devices in the EVPN instance.

    • On each PE device, you configure IRB interfaces with PIM in distributed designated router (DDR) mode. The PE device uses these IRB interfaces only to forward or route the multicast traffic on one or more VLANs to interested receivers locally (on its own device), rather than to send traffic out to other PE devices in the EVPN-MPLS network.

    • You can configure IGMP or MLD snooping in one or more routing instances of type evpn.

    • You must configure all VLANs on all PE devices.

    • Receivers in an EVPN instance can be single-homed to one PE device or multihomed to multiple PE devices in all-active mode. Peer PE devices for an EVPN segment synchronize IGMP or MLD state information by using BGP EVPN Type 7 and Type 8 (Join Sync and Leave Sync Route) messages.

    • The PE devices support IGMPv2 and IGMP snooping with any-source multicast (ASM) [(*,G)].

    • The PE devices support MLDv1, MLDv2, and MLD snooping as follows:

      • By default when you enable MLD snooping, the PE devices process MLDv1 and MLDv2 reports only in ASM (*,G) mode. They discard MLDv2 source-specific multicast (SSM) (S,G) reports.

      • If you enable MLD snooping with the SSM-only processing option (set evpn-ssm-reports-only at the [edit routing-instance instance-name protocols mld-snooping] hierarchy level), the PE devices process MLDv2 reports as SSM (S,G) only. They discard MLDv1 or MLDv2 ASM (*,G) reports. We also recommend that you configure MLDv2 on all IRB interfaces used for inter-VLAN routing in this case.

      PE devices can’t process both ASM and SSM reports together.

    [See Overview of Multicast Forwarding with IGMP or MLD Snooping in an EVPN-MPLS Environment.]

  • Multicast with IGMP or MLD snooping within VLANs for EVPN-MPLS (ACX5448, ACX5448-M, and ACX5448-D)—Starting in Junos OS Release 19.4R2, ACX5448 routers support intra-VLAN multicast forwarding with IGMP or MLD snooping in an EVPN over MPLS network as follows:

    • The multicast sources and receivers must be within an EVPN instance. You can configure IGMP or MLD snooping for one or more routing instances of type evpn.

    • Receivers can be single-homed to one provider edge (PE) device or multihomed to multiple PE devices (in all-active mode only).

    • The PE devices support IGMPv2 and IGMP snooping with any-source multicast (ASM).

    • The PE devices support MLDv1, MLDv2, and MLD snooping in intra-VLAN configurations as follows:

      • By default with MLD snooping enabled, the PE devices can process MLDv1 ASM (*,G) reports but discard MLDv2 reports.

      • With MLD snooping enabled, if you configure all interfaces that receive multicast traffic with MLDv2, the PE devices can process both MLDv1 and MLDv2 reports in ASM (*,G) mode, but they discard MLDv2 source-specific multicast (SSM) (S,G) reports.

    • You must configure each VLAN on all PE devices in an EVPN instance.

    • The PE devices flood multicast source traffic on a VLAN into the EVPN instance to reach all other PE devices. When they receive the traffic from the EVPN network, the PE devices use snooping information to forward the traffic only to the interested listeners in the VLAN.

    • Multihoming peer PE devices for an Ethernet segment (ES) exchange BGP EVPN Type 7 and Type 8 (Join Sync and Leave Sync Route) messages to synchronize the IGMP or MLD state information. When they receive multicast traffic from the EVPN core, the designated forwarder (DF) PE device forwards the traffic only to interested receivers based on IGMP snooping reports and Type 7 routes.

    [See Overview of Multicast Forwarding with IGMP or MLD Snooping in an EVPN-MPLS Environment.]

  • Support for IRB and IRBv6 on EVPN-MPLS networks (ACX5448)—Starting with Junos OS Release 19.4R2, you can configure EVPN with IRB or IRBv6 over an EVPN-MPLS network to extend Layer 2 connectivity across data centers. Both EVPN type 2 (MAC/IP Advertisement) and EVPN type 5 (IP Prefix Advertisement) routes are supported.

    [See EVPN with IRB Solution Overview.]

  • Support for EVPN E-Tree service (ACX5448)—Starting in Junos OS 19.4R2, you can configure an Ethernet VPN Ethernet Tree (E-Tree) service on ACX5448 routers.

    [See EVPN-ETREE Overview.]

What's New in Release 19.4R1


  • SPRING support for EVPN (ACX5448)—Starting in Junos OS Release 19.4R1, you can use Source Packet Routing in Networking (SPRING) as the underlay transport in EVPN on ACX5448 routers. SPRING tunnels enable routers to steer a packet through a specific set of nodes and links in the network.

    To configure SPRING, use the source-packet-routing statement at the [edit protocols isis] hierarchy level.

    [See Understanding Source Packet Routing in Networking (SPRING).]

  • Support for EVPN features on new hardware (ACX5448)—Starting with Release 19.4R1, Junos OS supports the following EVPN features:

  • Support for EVPN routing policies (ACX5448, EX4600, EX4650, EX9200, MX Series, QFX Series, and vMX)—Starting in Junos OS Release 19.4R1, Junos OS has expanded routing policy support to include the creation and application of policy filters specific to EVPN routes. You can create policies and apply policy filters to import and export EVPN routes at the routing-instance level or at the BGP level. Junos OS supports the following matching criteria for EVPN routes:

    • Route distinguisher ID

    • NLRI route type

    • EVPN Ethernet tag

    • BGP path attributes

    • Ethernet Segment Identifier

    • MAC Address on EVPN route type 2 routes

    • IP address on EVPN route type 2 and EVPN route type 5 routes

    • Extended community

    [See Routing policies for EVPN.]

Junos OS XML API and Scripting

  • Automation script library upgrades (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 19.4R1, devices running Junos OS that support the Python extensions package include upgraded Python modules. Python scripts can leverage the upgraded versions of the following modules:

    • idna (2.8)

    • jinja2 (2.10.1)

    • jnpr.junos (Junos PyEZ) (2.2.0)

    • lxml (4.3.3)

    • markupsafe (1.1.1)

    • ncclient (0.6.4)

    • packaging (19.0)

    • paho.mqtt (1.4.0)

    • pyasn1 (0.4.5)

    • yaml (PyYAML package) (5.1)

    [See Overview of Python Modules Available on Devices Running Junos OS.]

  • Python 3 support for commit, event, op, and SNMP scripts (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 19.4R1, you can use Python 3 to execute commit, event, op, and SNMP scripts on devices running Junos OS. To use Python 3, configure the language python3 statement at the [edit system scripts] hierarchy level. When you configure the language python3 statement, the device uses Python 3 to execute scripts that support this Python version and uses Python 2.7 to execute scripts that do not support Python 3 in the given release.

    The Python 2.7 end-of-support date is January 1, 2020, and Python 2.7 will be EOL in 2020. The official upgrade path for Python 2.7 is to Python 3. As support for Python 3 is added to devices running Junos OS for the different types of onbox scripts, we recommend that you migrate supported script types from Python 2 to Python 3, because support for Python 2.7 might be removed from devices running Junos OS in the future.

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



  • Support for Ethernet OAM and Metro Ethernet services over segment routing (ACX5448-D, ACX5448-M, MX Series)—Starting with Junos OS Release 19.4R1, ACX5448-D, ACX5448-M and MX Series routers support Ethernet OAM and Metro Ethernet services over segment routing.

    [See Understanding Adjacency Segments, Anycast Segments, and Configurable SRGB in SPRING for IS-IS Protocol, Understanding Topology-Independent Loop-Free Alternate with Segment Routing for IS-IS, Ethernet OAM Connectivity Fault Management .]

Routing Protocols

  • Support for configurable SRGB used by SPRING in OSPF protocols (ACX5448)— Starting in Junos OS Release 19.4R1, you can configure the segment routing global block (SRGB) range label used by segment routing. Labels from this range are used for segment routing functionality in OSPF domain.

    The SRGB is a range of the label values used in the segment routing. Prior to Junos OS Release 19.4R1, you could not configure the range for the SRGB block.

    Locally you can configure srgb start-label <label-range> index-range <index-range> command under [edit protocols ospf source-packet-routing] hierarchy or globally under [edit protocols mpls label-range] hierarchy.

    Following are the SRGB precedences for OSPF protocol:

    • Local SRGB

    • Global SRGB

    • Node-segment implementation of 256 label block

  • Unnumbered interface support for IS-IS and OSPFv2 with topology-independent loop-free alternate (ACX Series, MX Series and PTX Series)—Starting in Junos OS Release 19.4R1, you can enable IPv4 processing on a point-to-point interface without assigning it an explicit IPv4 address. The router borrows the IPv4 address of another Ethernet or loopback interface already configured on the router and assigns it to the unnumbered interface to conserve IPv4 addresses.

    To enable IPv4 processing for unnumbered interfaces include unnumbered-address source at the [edit interfaces [name] unit [name] family inet] hierarchy level.

    [See Configuring an Unnumbered Interface.]

System Logging

  • Improved intermodule communication between FFP and MGD (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 19.4R1, intermodule communication is improved to enhance software debugging. To enhance error messages with more context, the exit conditions from libraries have been updated as follows:

    • Additional information is now logged for MGD-FFP intermodule communication.

    • Commit errors that previously were only shown onscreen are now logged.

    We provide a new operational command, request debug information, to speed up the initial information-gathering phase of debugging.

    [See request debug information.]

Software Defined Networking (SDN)

  • Tunnel templates for PCE-initiated segment routing LSPs (ACX Series)—Starting in Junos OS Release 19.4R1, you can configure a tunnel template for Path Computation Element (PCE)-initiated segment routing LSPs and apply it through policy configuration. These templates enable dynamic creation of segment routing tunnels with two additional parameters – Bidirectional forwarding detection (BFD) and LDP tunneling.

    With the support for tunnel configuration, the LSPs that you would configure statically can now be automatically created from the PCE, thereby providing the benefit of reduced configuration on the device.

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

What's Changed

Learn about what changed in the Junos OS main and maintenance releases for ACX Series routers.

What’s Changed in 19.4R3

Routing Protocols

  • Advertising /32 secondary loopback addresses to Traffic Engineering Database (TED) as prefixes (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—In Junos OS Release, multiple loopback addresses export into 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 Junos OS releases, multiple secondary loopback addresses in TED were added into lsdist.0 and lsdist.1 routing tables as part of node characteristics and advertised them as the router-id.

What’s Changed in 19.4R2

There are no changes in behavior of Junos OS features and changes in the syntax of Junos OS statements and commands in Junos OS Release 19.4R2 for ACX Series routers.

What’s Changed in 19.4R1

General Routing

  • Support for full inheritance paths of configuration groups to be built into the database by default (ACX Series, MX Series, PTX Series, and SRX Series)—Starting with Junos OS Release 19.4R1, the persist-groups-inheritance option at the [edit system commit] hierarchy level is enabled by default. To disable this option, use no-persist-groups-inheritance.

    [See commit (System).]

Routing Protocols

  • XML RPC equivalent included for the show bgp output-scheduler | display xml rpc CLI command (ACX Series, EX Series, MX Series, PTX Series, QFX Series, and SRX Series)—Starting in Junos OS Release 19.4R1, we have included an XML RPC equivalent for the show bgp output-scheduler | display xml rpc CLI command. In Junos OS releases before Release 19.4R1, the show bgp output-scheduler | display xml rpc CLI command does not have an XML RPC equivalent.

    [See show bgp output-scheduler.]

Known Limitations

Learn about known limitations in Junos OS Release 19.4R3 for ACX Series routers. For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • All PTP packets go to the best-effort queue instead of the network control queue. This is because of the limitation on Qumran where DSCP values are not preserved. PR1361315

  • ACX6360 Junos telemetry interface or telemetry infrastructure does not support the interface-filtering capability. Therefore, after you enable a particular sensor for telemetry, it is turned on for all the interfaces. PR1371996

  • When a timing configuration and the corresponding interface configuration are flapped for multiple times in iteration, PTP is stuck in "INITIALIZE" state where the ARP for the neighbor is not resolved. In issue state, BCM hardware block get into inconsistency state, where the lookup is failing. PR1410746

  • The port LEDs glowing during system/vmhost halt state is the expected behavior across all ACX Series platforms. Even the system LED glows during halt state. PR1430129

  • If L2VPN sessions have OAM control-channel option set to router-alert-label, the no-control-word option in L2VPN shouldn't be used for BFD sessions to come up. PR1432854

  • The IFL statistics in ACX5448, will display the full packet size similar to the behavior in ACX5000 series. PR1439124

  • With an asymmetric network connection, EX: 10G Macsec port connected to a 10GbE channelized port, high and asymmetric T1 and T4 time errors introduce a high two-way time error.This introduces different CF updates in forward and reverse paths. PR1440140

  • With the MACsec feature enabled and introduction of traffic, the peak-to-peak value varies with the percentage of traffic introduced. Find the maximum and mean values of the Time errors with different traffic rates(two-router scenario). Can have maximum value jumps as high as 1054ns with 95% traffic, 640ns with 90% traffic, and 137ns with no traffic. PR1441388

  • ACX Series platforms do not support directly associating a policer in an a logical interface. The association needs to be achieved using "filters" only. In this case, "family any" filter can be configured. Also, the ACX5448 hardware ASIC does not support "egress policing". Egress shaping (H-QoS at the logical-interface level) can be used instead. PR1446376

  • ACX Series routers support only 900 joins of IGMPv3 users per second. PR1448146

  • This is hardware limitation and this is expected behavior on ACX5448. The mac-ageing on ACX5448 will not be at the granularity of per second. Ageing is at the granularity of an ageing cycle. Ageing cycle is defined as 1/6th of the age configured. Only 16000 entries can be aged in each ageing cycle. Meaning that if we have more than 16000 entries ageing in an ageing cycle, only 16000 will be aged out. Rest would be aged out in the subsequent cycles. 16000 can be achieved in ideal scenario when we don't have another learning event in the same cycle. Also, this number can vary in the event of more load on the system. This is a hardware limitation. PR1509590

Open Issues

Learn about open issues in Junos OS Release 19.4R3 for ACX Series routers. For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • Loopback status is not shown for OT interfaces on CLI (available from vty only). PR1358017

  • The SD (Signal Degrade) threshold is normally lower than the SF threshold (that is, so that as errors increase, SD condition is encountered first). For the ACX6360 optical links there is no guard code to prevent the user from setting the SD threshold above the SF threshold which would cause increasing errors to trigger the SF alarm before the SD alarm. This will not cause any issues on systems with correctly provisioned SD/SF thresholds. PR1376869

  • Enhancement is needed for FRR BER threshold SNMP support. PR1383303

  • On ACX6360/PTX10001 router, Tx power cannot be configured using + sign. PR1383980

  • The switchover time observed was more than 50 minutes under certain soak test conditions with an increased scale with a multiprotocol multirouter topology. PR1387858

  • The ccc logs are not compressed after rotation. PR1398511

  • A jnxIfOtnOperState trap notification is sent for all ot-interfaces. PR1406758

  • On ACX 1000/2000/4000/5048/5096 platforms, after a new child IFL with VLAN and filter is added on an aggregated Ethernet physical interface or if the VLAN ID of a child logical interface is changed with filter, traffic over the aggregated Ethernet physical interface might get filtered with that filter on the child logical interface. For example, ae-0/0/0 is a physical interface and ae-0/0/0.100 is a logical interface. PR1407855

  • Layer 2 rewrite is happening on regular bridge domain and VLAN interfaces, although there are some service dependencies (VPLS in this case) due to which, the egress interface map table is not updated properly with the Layer 2 rewrite map ID; as a result, the rewrite does not work. PR1414414

  • On ACX5048/ACX5096 platforms, traffic loss and SNMP slow response issues could be seen where an optic transceiver is removed and inserted back to the same interface. Manually restarting Packet Forwarding Engine might also trigger this defect. PR1418696

  • On an ACX5000 platform, high CPU usage by the fxpc process might be seen under a rare condition if parity errors are detected in devices. This issue has no direct service/traffic impact. However, because CPU utilization is high during this issue, there are some side effects. For example, the issue could impact time-sensitive features such as BFD. PR1419761

  • On an ACX5448, the request system reboot command triggers a reboot on the host (Linux) instead of just being limited to Junos OS. PR1426486

  • 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

  • Protocols get forwarded when using a nonexisting SSM map source address in IGMPv3 instead of pruning. This is a day 1 design issue, and needs a design solution. PR1435648

  • Timing on 1G, performance is not at par compared with 10G, compensation is done to bring the mean value under class-A but the peak-to-peak variations are high and can go beyond 100ns. It has a latency variation with peak to peak variations of around 125ns-250ns(that is, 5-10% of the mean latency introduced by the each phy which is of around 2.5us) without any traffic. PR1437175

  • Memory leaks are expected in this release. PR1438358

  • ACX Series routers support only 900 joins of IGMPv3 users per second. PR1448146

  • Drop profile maximum threshold may not be reached when the packet size is other than 1000 bytes. This is due to the current design limitation. PR1448418

  • In some cases when there is a failure of the I2C daemon, this might result in riofeb crash on ACX5448. PR1455928

  • IPv6 BFD sessions when configured below 100ms was getting flapped which will not after this bug. PR1456237

  • On the PTX10001/ACX6360 platforms, the unionfs filesystem may get full on vmhost, this bacause there is a mail package in the WRlinux 8 continue to fill the mail logs into the unionfs filesystem. This issue will cause the router to hand and bring traffic down. PR1470217

  • On PTX1000/ACX6360 Series platforms, the vmhost disk usage might keep increasing due to an incorrect sensor path. PR1480217

  • ACX platforms - BFD over L2VPN/ L2Circuit will not work due to ACX platforms' SDK upgrade to version 6.5.16. PR1483014

  • On PTX1000/PTX10001/ACX6360 Series platforms, the port mirror will not work when the port-mirroring is configured with firewall filter. PR1491789

  • When the DF interface is flapped, the traffic is doubled. As the current Non-DF also forwards the traffic in EVPN Multihoming scenario. Work around is to clear the multicast route, with that the issue won't be seen. PR1502411

  • ACX6360: Observed core-ripsaw-node-aftd-expr. PR1504717

  • MPLS : mpls_lsp check is failing while verifying basic lsp_retry_limit After the fix for PR-1487532, we reset the src_address of the lsp to 0 (if src_address is not configured) whenever it changes its state from Up to down. So when the ingress-lsp goes to down state, we are resetting it to 0. The script is failing because the script is checking for src_address to be present for the ingress-lsp session. Script change is required. PR1505474

  • In PTP environment some vendor devices acting as slave expecting announce messages at an interval of -3 (8pps) from upstream master device. As of today announce message are configurable in range of 0 to 3. To support the above requirement engineering provided a hidden cli knob "set protocol ptp master announce-interval -3". In the networks/design where we have this requirement we can configure the hidden cli otherwise regular cli which is in the range (0 to 3) can be configurable. Both the cli knobs are mutually exclusive, commit error is expected if both are configured. This new change is applicable to ACX platforms only excluding ACX5000. PR1507782

  • CLI mentioned in workaround is required when same User MAC is configured on both EVPN DH routers. PR1509808

  • After link connection flap between the PHP node and the egress PE node, the VRF traffic which supposed to PHP and sent only with VPN label out to egress PE, would wrongly tagged with both MPLS label and VPN label. PR1512821

  • Interface not coming up with Auto-negotiation setting between ACX1100 and QFX/MX/ACX as other end. PR1523418

  • This classifier display got blocked due to PR 1353828, where they are blocking the classifier display function as ACX supports only IFD based classification. PR1531413

  • The CLI output of chassis network-services is not reflecting the configured mode though the configured mode is correctly programmed in Kernel. PR1538869

  • Ospf neighbor state is INIT instead of expected FULL. PR1543667

Platform and Infrastructure

  • The CFM remote MEP not coming up after configuration or remains in Start state. PR1460555

Virtual Chassis

  • ACX5000 reports false parity error messages like soc_mem_array_sbusdma_read. The ACX5000 SDK can raise false alarms for parity error messages like soc_mem_array_sbusdma_read. This is a false positive error message. PR1276970

Resolved Issues

Learn which issues were resolved in the Junos OS main and maintenance releases for ACX Series routers.

For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

Resolved Issues: 19.4R3

General Routing

  • Policer discarded count is also shown incorrectly to the enq count of the interface-Queue But Traffic Behavior is fine as expected. PR1414887

  • gigether-options configuration statement enabled again under interface hierarchy. PR1430009

  • While performing repeated power-off/power-on of device, we see SMBUS Transactions timeout. PR1463745

  • The links may not come up when 100-Gigabit Ethernet interface is channelized to 4x25-Gigabit Ethernet interfaces. PR1479733

  • Memory utilization enhancement on ACX Series platforms. PR1481151

  • The packets might not get processed on the interfaces after unified ISSU. PR1483959

  • FPC might crash on ACX5448 platform. PR1485315

  • The queue statistics are not as expected after configuring the IFD and logical interface shaping with the transmit rate and scheduler-map. PR1488935

  • ACX5448 chassis mac-address and label mac-address may not match. PR1489034

  • IEEE 802.1p Priority and DEI values in locally generated VLAN-based IP packets may be changed when sourced from IRB interface on ACX5000. PR1490966

  • VPLS flood gorups results in IPv4 traffic drop after core interface flap. PR1491261

  • LACP control packets may be dropped due to high CPU utilization in ACX5048/ACX5096. PR1493518

  • During speed mismatch, QSFP28/QSFp+ the optics/cables may or may not work. PR1494600

  • Outbound SSH connection flap or memory leak issue might be observed when pushing configuration to ephemeral database with high rate. PR1497575

  • ACX5448 EXP rewrite is not working for L3VPN sends all traffic with incorrect EXP. PR1500928

  • The error message mpls_extra NULL might be seen during MPLS route add/change/delete operation. PR1502385

  • SFW sessions might not get updated on ms interfaces in ACX500. PR1505089

  • PIC slot may be shut down less than 240 seconds due to the over-temperature start time is handled incorrectly. PR1506938

  • BFD flapping with the error ACX_OAM_CFG_FAILED: ACX Error (oam):dnx_bfd_l3_egress_create : Unable to create egress object after random time interval. PR1513644

  • In ACX platforms, the loopback filter cannot take more than 2 TCAM slices. PR1513998

  • The VM process generates a core file while running stability test in a multidimensional scenario. PR1515835

  • L2ALD crash is seen during stability test with traffic on scaled set-up. PR1517074

  • IPV6 neighbor state change causes "Local Outlif" to leak by two values leads to DNX_NH::dnx_nh_tag_ipv4_hw_install errors. PR1519372

  • The show class-of-service interface does not show classifier information on ACX Series devices. PR1522941

  • The statement vlan-id-list may not work as expected on the ACX5448/ACX710 platforms. PR1527085

  • Memory leak in Local OutLif in VPLS/CCC topology. PR1532995

Interfaces and Chassis

  • FPC crash might be observed with inline mode CFM configured. PR1500048

Routing Protocols

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

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


  • The l2circuit neighbor might be stuck in RD state at one end of MC-LAG peer. PR1498040

  • The rpd crash could be seen in certain conditions after deleting l2circuit configuration. PR1502003

Resolved Issues: 19.4R2

General Routing

  • On ACX5000, MacDrainTimeOut and bcm_port_update failed: Internal error. PR1284590

  • On ACX5048 and ACX5096 platforms, high CPU for fxpc processes might be observed on class-of-service configuration changes on interfaces. PR1407098

  • Drift messages in ACX2200, which is a PTP hybrid (PTP + Synchronous Ethernet) device. PR1426910

  • ACX5448-D interfaces support: The input bytes value in the show interfaces extensive is not in par with older ACX or MX. PR1430108

  • The l2cpd process might crash and generate a core file when interfaces are flapping. PR1431355

  • Fans on an ACX5448-M might not be running at the correct speed. PR1448884

  • ACX5048 SNMP polling is stalled after the link is flapped or the SFP transceiver is replaced, and ACX_COS_HALP(acx_cos_gport_sched_set_strict_priority:987): Failed to detach logs is seen. PR1455722

  • ACX5448-D and ACX5448-M devices do not display airflow information and temperature sensors as expected. PR1456593

  • [interface] [generic] [ACX] not able to add more than 16 links in a LAG. PR1463253

  • RED drop on interface is seen even when there is no congestion. PR1470619

  • CoS: Egress queue statistics are not applicable to ae interfaces on ACX5048. PR1472467

  • dcpfe core files are generated when you disable and then enable MACsec through Toby scripts. PR1479710

  • ACX5448 Layer2 VPN with interface ethernet-ccc input-vlan-map/output-vlan-map might cause traffic to be silently dropped. PR1485444

  • LSP (primary/standby) does not Act/Up after routing or rpd restart. PR1494210

Interfaces and Chassis

  • MC-AE interface might display unknown status if the subinterface is added as part of the VLAN on the peer MC-AE node. PR1479012

Layer 2 Ethernet Services

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


  • BGP session might keep flapping between two directly connected BGP peers because of the incorrect TCP-MSS in use. PR1493431

Resolved Issues: 19.4R1

General Routing

  • On ACX5000 MacDrainTimeOut and bcm_port_update failed: Internal error error is seen. PR1284590

  • bcmDPC task is high even though Interuppt START_BY_START flag is set to 0. PR1329656

  • The AE interface with LACP stays down after the router reboots if link-speed is configured. PR1357012

  • On ACX Series devices, the LED on the GE interface goes down when speed 10M is added. PR1385855

  • Link Fault Signaling (LFS) doesn not work on ACX5448 10-, 40-, and 100-Gigabit Ethernet interfaces. PR1401718

  • The optic comes with Tx enabled by default. Because the port is administratively disabled, the port is stopped. However, because the port has not been started, it does not disable Tx. PR1411015

  • The ACX5448:40G FEC on ACX5448, which is FEC enabled by default, must be aligned with the MX and QFX platforms, where FEC is NONE. PR1414649

  • On the ACX5448-X:SKU and ACX5448-D, 96000 ARPs get populated. However, only 47000 NH entries are present. Around 50 percent of packet drop is observed. PR1426734

  • Chassisd might crash with unsupported hcos configuration when an MX104 is used as a fusion aggregation device. PR1430076

  • The l2cpd process might crash and generate a core file when interfaces flaps. PR1431355

  • Deviation in traffic rate in the queue is around 8 % to 10% percent in some cases. PR1436297

  • 1PPS performance metrics (class A) of G.8273.2 are not met for 1G interfaces because of the variable latency added by the Vittesse PHY. PR1439231

  • The interface on ACX1100 devices remains down when using SFP-1FE-FX (740-021487). PR1439384

  • Transit DHCP packets are not punted to CPU and are transparently passthrough. PR1439518

  • When the interface is flapped between channelized configurations, 25-Gigabit Ethernet to 100-Gigabit the aggregated Ethernet interface configuration is not cleaned up properly. PR1441374

  • In an ACX5448 platforms, when the PFE failed to allocate packet buffer, portion of packet memories may not be freed. PR1442901

  • RED drops might be seen after link flaps or CoS configuration changes. PR1443466

  • ACX5448/18.3R1-S4.1 is not performing proper dot1p CoS rewrite on interfaces configured with l2circuit/local-switching/family ccc. PR1445979

  • On ACX Series, the auto exported route between VRFs might not respond for icmp echo requests. PR1446043

  • l2circuit with a backup-neighbor (hot-standby) configured might stop forwarding traffic after failovers. PR1449681

  • oper-state for et interface does not transition from 'init' to 'Normal'. PR1449937

  • RMPC core files are found after configuration changes done on the network for PTP/Clock Synchronization. PR1451950

  • After disabling 100G and 40G interface Laser output power in show interfaces diagnostics optics shows some values. PR1452323

  • ACX5448 FPC crashed due to segmentation fault. PR1453766

  • Incorrect operating state is displayed in snmp trap for fan removal. PR1455577

  • Enable gigether option to configure Ethernet FEC on client ports. PR1456293

  • ACX5448-D and ACX5448-M Devices does not display airflow information and temperature sensors as expected. PR1456593

  • ACX5448 Layer2 VPN with encapsulation-type ethernet stops passing traffic after a random port is added with vlan configuration. PR1456624

  • The rpd crash might be seen if BGP route is resolved over same prefix protocol next-hop in inet.3 table which has both RSVP and LDP routes. PR1458595

  • Route resolve resolution is not happening when the packet size is 10000. PR1458744

  • The traffic might be blackholed during link recovery in an open ethernet access ring with ERPS configured. PR1459446

  • ACX5000: SNMP mib walk for jnxOperatingTemp not returning anything for FPC in new versions. PR1460391

  • ACX5448-M Interfaces and Optics support: on enabling local loopback 10G interface is going down. PR1460715

  • ACX5448-D Interfaces and Optics support: sometimes during the bring up of AE interface there are ARP resolution issues. PR1461485

  • ACX Series routers LLDP neighbor not up on lag after software upgrade to Junos OS Release 18.2R3-S1. PR1461831

  • RED drop on interface, no congestion. PR1470619

Layer 2 Ethernet Services

  • DHCP request might get dropped in DHCP relay scenario. PR1435039

Platform and Infrastructure

  • REST API process will get non-responsive when a number of request coming with a high rate. PR1449987

Routing Protocols

  • Loopback address are exported into other VRF instance might not work on EX/QFX/ACX platforms. PR1449410

  • MPLS LDP might still use stale MAC of the neighbor even the LDP neighbor's MAC changes. PR1451217

  • The rpd might crash continuously due to memory corruption in an IS-IS setup. PR1455432

Documentation Updates

This section lists the errata and changes in Junos OS Release 19.4R3 for the ACX Series documentation.

Feature Guides Are Renamed As User Guides

  • Starting with Junos OS 19.4R1, we renamed our Feature Guides to User Guides to better reflect the purpose of the guides. For example, the BGP Feature Guide is now the BGP User Guide. We didn’t change the URLs of the guides, so any existing bookmarks you have will continue to work. To keep the terminology consistent on our documentation product pages, we renamed the Feature Guides section to User Guides. To find documentation for your specific product, check out this link.

Migration, Upgrade, and Downgrade Instructions

This section contains the upgrade and downgrade support policy for Junos OS for the ACX Series Router. Upgrading or downgrading Junos OS might take several minutes, depending on the size and configuration of the network.

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

Upgrade and Downgrade Support Policy for Junos OS Releases

Support for upgrades and downgrades that span more than three Junos OS releases at a time is not provided, except for releases that are designated as Extended End-of-Life (EEOL) releases. EEOL releases provide direct upgrade and downgrade paths—you can upgrade directly from one EEOL release to the next EEOL release even though EEOL releases generally occur in increments beyond three releases.

You can upgrade or downgrade to the EEOL release that occurs directly before or after the currently installed EEOL release, or to two EEOL releases before or after. For example, Junos OS Releases 17.1, 17.2, and 17.3 are EEOL releases. You can upgrade from Junos OS Release 17.1 to Release 17.2 or from Junos OS Release 17.1 to Release 17.3.

You cannot upgrade directly from a non-EEOL release to a release that is more than three releases ahead or behind. To upgrade or downgrade from a non-EEOL release to a release more than three releases before or after, first upgrade to the next EEOL release and then upgrade or downgrade from that EEOL release to your target release.

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

For more information about EEOL releases and to review a list of EEOL releases, see