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Open Issues

Learn about open issues in Junos OS Release 21.4R2 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

  • For ACX710, if the console cable is plugged in and the terminal connection is active and sending characters to the interface, the system boot might be interrupted and the ACX710 boot will be stalled at the uboot# prompt. PR1513553

  • Due to BRCM KBP issue route lookup might fail. Need to upgrade KBP to address this issue, Due to high risk KBP SDK upgrade planned for 21.1. PR1533513

  • On ACX5448 platforms, if hierarchical-scheduler is configured for an interface, during interface flaps or configuration changes, some of Packet Forwarding Engine buffers might become out of sync, which might cause packet drops even without congestion. PR1603622

  • On ACX platforms, traffic issue might be observed with downstream devices when Precision Time Protocol (PTP) is configured (G.8275.1 PTP profile) along with PHY timestamping and Multiprotocol Label Switching (MPLS) terminated on 10G interface. The transit PTP IPv4 packets are updated with incorrect Correction Factor(CF). This issue could be restored by disabling PHY stamping. However, disabling might impact the PTP performance. PR1612429

  • For ACX5448, MX204, and MX2008 "VM Host-based" platforms, starting with Junos OS Release 21.4R1 or later, ssh and root login is required for copying line card image (chspmb.elf for MX2008) from Junos VM to Linux host during installation. The ssh and root login are required during installation. Use "deny-password" instead of "deny" as default root-login option under ssh config to allow internal trusted communication. Ref PR1629943

  • When multihop BFD is configured in ACX5448, delegated BFD sessions are not coming up. PR1633395

  • When ACX710/5448 series platforms work as provider edge nodes in Layer 3 VPN environment, it might stop forwarding Layer 3 VPN traffic after core-facing link flaps, due to a race condition that happens during Layer 3 VPN NH programming in Packet Forwarding Engine. PR1635801

  • Delegated/Inline BFD sessions configured in non-default VR will not work as support for L3 Inject is missing. PR1649806

  • On ACX5448 and ACX710 platforms, traffic drop might be observed for some MAC entries which are learned on interchassis control link (ICL) instead of multichassis link aggregation (MC-AE). PR1653926

Routing Protocols

  • When inline add event for IPv6 inline BFD session comes without resolving neighbor for nexthop , inline event addition will fail. PR1650677


  • On all Junos platforms with MVPN scenario, stale PIM (S, G) state might be seen when there are no local/remote receivers and the multicast source is inactive. Only stale PIM entry will be seen, and it doesn't impact MVPN service or functionalities. PR1536903