Description

This article explains the "saw dest err on plane" log messages observed on SRX5000 series devices and how they may lead to FPC (Flexible PIC Concentrator) restarts.

Symptoms

Repeated log entries similar to the following are observed in the messages file:

FM FPCx: (FPC x FE y) saw dest err on plane n for dests (fpc z pfe a)

 

Multiple FPCs report destination errors toward a specific FPC.Example pattern: Several FPCs logging destination errors pointing to the same target FPC.In some cases, one or more FPCs may restart automatically.
 

Solution

The log message indicates internal communication issues within the chassis, specifically between:

  • Packet Forwarding Engines (PFE)
  • Routing Engine (RE)
  • Fabric planes and switching components

When an FPC becomes unresponsive or experiences communication failures:

  • Other FPCs report destination errors toward the affected FPC
  • The system detects instability in the internal fabric communication

As part of its recovery mechanism, the SRX5K platform may:

  • Trigger a soft restart of FPCs to restore proper communication

 

Initial Checks / Workarounds

Perform the following troubleshooting steps:

  1. Verify Power Stability

    • Ensure all power supplies are functioning correctly and providing stable input.

  2. Reset Fabric Plane

    • Take the affected fabric plane offline and bring it back online.

  3. Re-seat Hardware Components

    • Re-seat the affected FPC(s)
    • Inspect for bent or damaged pins
    • Re-seat the associated SCB (Switch Control Board)

If the issue persists:

  1. Swap FPC to Another Slot

    • Move the affected FPC to a different slot
    • Check whether the error follows the FPC (indicating a faulty card)

  2. Swap SCB

    • Replace or swap the SCB to rule out fabric-related issues

If none of the above steps resolve the issue:

  • Collect RSI and var logs. 
  • Contact JTAC (Juniper Technical Assistance Center) for further investigation

Modification History

2023-10-11 : Article Created

Related Information

Tracked on PR : https://gnats.juniper.net/web/default/1746383#audit_tab