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Network Port Flap

Use the Marvis Actions dashboard to identify flapping ports.

The Network Port Flap event identifies router ports that persistently go up and down in a rapid manner. The instability resulting from port flapping disrupts network connectivity and degrades the end-user experience. Some of the reasons for port flapping are:

  • Faulty cables and connectors.

  • Mismatch in duplex settings of the connected devices.

  • Hardware or software malfunctions on the router.

  • Inconsistent power supply or power surges.

To view the Network Port Flap event, click Marvis > Router > Network Port Flap.

The Network Port Flap event provides details such as the site, router, date and time when the event was recorded, event status and even the recommended action to resolve the event. Click View More to view the list of ports that flapped.

You can disable the router's ports to address port flapping temporarily. Disabling the ports stops the immediate flapping and can stabilize the network temporarily.

Note: You can disable the ports as an initial step in troubleshooting the issue. However, it is not a permanent solution to fix port flapping.

To disable the router's flapping port/ports, see Disable Flapping Ports.

As a basic troubleshooting step, network administrators can check the cable connection and perform the loopback diagnostic test. You can further investigate the flapping ports from the router CLI using the following CLI commands:

  1. Check the physical link status of the interface with the command: show interfaces interface-name media

  2. Check the interface statistics in detail with the command: show interface interface-name extensive

If you find any outliers here, contact your Juniper Support representative to resolve the event.

You can mark the status of an event as In Progress to indicate that an administrator is working on resolving the event. Resolving a specific event will only resolve that occurrence of the event and will not resolve future occurrences of the same event.

Figure 1: Marvis Actions: Network Port Flap Marvis Actions Dashboard on Juniper Routing Assurance displaying Network Port Flap event and detailed information about the selected event along with a recommended action to resolve the issue.

Disable Flapping Ports

To disable the router's flapping port/ports:
  1. Click Marvis > Router > Network Port Flap.
  2. In the NETWORK PORT FLAP widget, select the router whose port/ports you choose to disable.
  3. Click DISABLE PORT.
    The Disable Ports pop-up appears.
  4. You can disable multiple ports at once. Select the ports that you want to disable. Click OK.
    Warning:

    The Disable Port event might be service impacting. Click Cancel to abort the action.
    The port is immediately disabled.
Navigate to Routers:Router Name > Port List to verify the status of the port. The status of the port should be down.
Disabling the ports stops the immediate flapping and can stabilize the network temporarily. However, turning interfaces off causes service downtime. You can disable the ports as an initial step in troubleshooting the issue.
Note: Once the ports are disabled, they are not automatically enabled. You must explicitly re-enable the disabled ports. You can re-enable the port using the Bounce Port tool in the Front Panel tab on the Routers:Router Name page or underusing router Utilities. For more information, see Bounce Ports.
Figure 2: Network Port Flap: Disable Ports Marvis Actions Dashboard on Juniper Routing Assurance displaying Network Port Flap event type. The screenshot also displays the steps to disable selected router ports.