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Known Behavior


This section lists known behavior, system maximums, and limitations in hardware and software in Junos OS Release 15.1R7 for the QFX Series.

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

High Availability (HA) and Resiliency

  • On QFX5100 switches, Fibre Channel over Ethernet (FCoE) traffic might be dropped for up to 4 seconds during an in-service software upgrade (ISSU) when FCoE Initialization Protocol (FIP) snooping is enabled. PR981306

  • On EX4600 and QFX5100 switches, the Link Aggregation Control Protocol (LACP) in either slow mode or fast mode might go down and then come back up, causing a timeout and a service outage during an in-service software upgrade (ISSU) or a nonstop software upgrade (NSSU). In addition, after the master Routing Engine is rebooted, the switches might experience intermittent traffic loss on non-LAG interfaces, and redundant trunk group (RTG) convergence times might be long. PR1031338

Interfaces and Chassis

  • On an EX4300 or a QFX5100 switch, a MAC address that is specified as part of a MAC-based VLAN is authenticated on an interface (for example, on xe-1/1/1), on which 802.1X authentication in multiple supplicant mode is configured. However, the same MAC address might not be authenticated on another interface, for example, xe-2/1/1, if the MAC address moves to interface xe-2/1/1 from interface xe-1/1/1. PR1007589

  • On an MC-LAG, if an ARP for a host is learned on the MC-LAG interface and the host changes its MAC address without sending a gratuitous ARP, traffic loss might occur. PR1009591

  • On QFX5100 switches, if you configure MC-LAG, IRB mac sync, and LACP force up, the number of packets received (rx) might be twice the amount sent (tx) from the customer edge to the core. PR1015655

  • On a QFX5100 switch, you might be unable to commit the configuration if you modify the subnet of an IP address on an IRB interface by using the replace pattern command. PR1119713

  • On QFX5100 Virtual Chassis, generic routing encapsulation (GRE) counters might not increment with a firewall filter and PIM configured. PR1124170

  • On a QFX5100 or EX4600 switch, high ICMP delays are experienced when pinging directly connected integrated routing and bridging (IRB) interfaces. This is caused by a hardware limitation. Transit traffic is not affected. PR1164135

  • On QFX5100 switches, Layer 2 control frames with a destination MAC address of 01:80:c2:00:00:02 and an ethertype of 8809 might be dropped at the egress PE router Layer 2 VPN. PR1182124

Layer 2 Features

  • On a mixed-mode Virtual Chassis Fabric (VCF) with interface-mac-limit configured, if you remove the complete mac-limit configuration, the mac-limit behavior might remain. As a workaround, try rebooting the device. PR1044460

  • On ELS (Enhanced Layer 2 Software) platforms (including EX4300, EX4600, EX9200, QFX3500, QFX3600, and QFX5100 switches), if Q-in-Q tunneling is enabled, if you configure an RTG (redundant trunk group) on a Q-in-Q interface, the RTG configuration cannot be applied; there is a commit check error. PR1134126

  • On QFX5100 switches with a CoS classifier configured on an AE interface, if you add or delete a subinterface, traffic loss of approximately 10 packets might occur while you are committing the changes. PR1162963

  • On a QFX5100 switch, with a fully meshed MC-LAG topology configured, sometimes there is more traffic loss when the ICL interface goes down and then back up compared with when you have Junos OS Release 14.1X53-D35 software installed. The root cause has been identified, and this issue does not affect MC-LAG functionality. PR1209322

Multicast Protocols

  • When an IGMP leave is sent from a host to a QFX5100 switch, one packet per multicast group is dropped during route programming. PR995331

Multiprotocol Label Switching (MPLS)

  • On a QFX5100 switch, if an MPLS link is in hot standby mode and a pseudowire switchover is triggered by the event "remote site local interface signaled down," traffic flowing through the pseudowire might drop. PR1027755

Platform and Infrastructure

  • Traffic convergence delay time for link protection, node-link protection, and fast reroute is more than 50ms for the QFX5100-48T switch. PR1026957

Routing Policy

  • On the QFX Series, in a BGP equal-cost multipath (ECMP) scenario, if the import policy uses the policy action next-hop peer-address to set the route's protocol next-hop, BGP multipath might use more ECMP groups than necessary. If the ECMP entries exceed the maximum supported by the hardware, traffic loss might occur. As a workaround, use the policy action next-hop ip-address instead of the action next-hop peer-address.

Routing Protocols

  • On a QFX Series Virtual Chassis, if you delete a member of a LAG associated with an IRB interface, the counter for the filter applied to the IRB interface might reset. PR898171

  • On EX4300, EX4600, and QFX Series switches, a Bidirectional Forwarding Detection (BFD) session might not come up when BFD version 0 is configured. As a workaround, deactivate or delete the version configuration. PR1076052

Software-Defined Networks (SDN)

  • On QFX5100 switches, if more than 1K virtual extensible LAN network identifiers (VNIs) are created by Open vSwitch Database (OVSDB), the VTEP gateway daemon (vgd) might generate a core file. PR1075189

Software Installation and Upgrade

  • On EX4600, QFX3500, and QFX5100 switches, the amount of time that it takes for Zero Touch Provisioning to complete might be lengthy because TFTP might take a long time to fetch required data. PR980530

  • On EX Series or QFX Series Virtual Chassis or Virtual Chassis Fabric (VCF), nonstop software upgrade (NSSU) cannot be used to upgrade from a Junos OS Release 14.1X53 image to a Junos OS Release 15.1 or later image. PR1087893

Spanning-Tree Protocols

  • On QFX5100 Virtual Chassis interfaces on which the flexible-vlan-tagging statement is specified, STP, RSTP, MSTP, and VSTP are not supported. PR1075230

Virtual Chassis and Virtual Chassis Fabric (VCF)

  • In a mixed Virtual Chassis or Virtual Chassis Fabric (VCF), the show pfe filter hw summary command is not supported for an EX4300 member of the Virtual Chassis or VCF. PR1019377

  • On a QFX5100, QFX3600, QFX3500, or EX4300 switch, if you remove a transceiver from an interface and then reinsert it in the interface within 30 seconds after you have issued the set virtual-chassis vc-port set command to convert the interface into a Virtual Chassis port (VCP), the VCP is not created. PR1029829

  • On a QFX5100 Virtual Chassis, frequent MAC move events can put the system into an inconsistent state, which results in a Packet Forwarding Engine manager (FXPC) process crash with a core file generated. PR1086108

  • On QFX3500 and QFX3600 Virtual Chassis, any change in channelization causes the Packet Forwarding Engine to restart. If you apply channelization across various member switches in the Virtual Chassis, connectivity might be lost temporarily. PR1105371

  • In a mixed mode Virtual Chassis with QFX3500 switches, if multicast packets are sent to the Routing Engine at a high rate, the Virtual Chassis might become unresponsive. PR1117133


  • On a QFX5100 switch that has performed a pseudowire switchover, traffic might drop for 10 seconds immediately after the switchover. PR1049606