Loop Detection

1. Summary

This page is for configuring the settings for loop detection.

This function monitors whether a loop is occurring by sending its loop detection frame from the port and whether the frame returns to itself or not.

2. Top page

This is the top page for the loop detection.

2.1. System settings

Displays the system settings of loop detection.
The table items are explained below.
- Displays the loop detection settings for the entire system.
- Displays the setting for whether to disable Port Blocking immediately or periodically after the loop is resolved.
- Displays the setting for automatic recovery from Shutdown (errdisable state).
- Press the "Setting" button to display the page for configuring the loop detection settings for the entire system.
Reset the loop detection status
- You can immediately resolve the loop detection states (e.g., Shutdown) by reset feature.

2.2. Interface settings

Displays the settings and operating status of loop detection for each interface.
The table items are explained below.
- Check box
  Check the checkbox to perform batch settings and initialize settings.
- Port
  Displays the port interface name.
- Loop detection
  Displays the settings of loop detection for the interface.
- Port Blocking
  Displays the settings of Port Blocking function.
  If it is enabled, the function blocks frames when a loop is detected.
- Status
  Displays the operating status of loop detection.
  - Operating
    The loop detection function is operating.
  - Detected
    Loop has been detected. Communication is continued.
  - Blocking
    Frames are being blocked. (Communication will resume in 5 seconds after the loop is resolved.)
  - Shutdown
    The port is shutting down. (Communication will resume in 5 minutes after shutdown.)
  - Stopped
    The loop detection function is stopped.
    Normally, the state becomes "Stopped" when the loop detection setting is disabled.
    If it is stopped by other factors, the following factors are indicated in parentheses.
    
    Sniffer port
    If it is a port with mirroring settings (sniffer port)
    
    STP
    You can use the loop detection function with spanning tree. However, the function works only when the spanning tree status of the corresponding port is "Forwarding".
Press the "Setting" button to display the page for configuring the selected interface settings.
Press the "Specify all" button to configure the settings for all interfaces with the check box selected.
Press the "Return to defaults" button to initialize the settings for all interfaces with the check box selected.
- Each of the default settings are shown below.
  - Loop Detection: Enabled
  - Port Blocking: Enabled (Block frames when a loop is detected)
Press the "Update" button to update the table of interface settings.

This page is for configuring the interface settings for loop detection.
Enter the settings, and then press the "Confirm" button.
If there are no mistakes in the input content of the confirmation screen, press the "OK" button.

3.1. System settings

Specify whether to enable or disable the loop detection function for the entire system.
Even if set to enable, the loop detection function for an individual port does not work if the port’s setting is disabled.
If this function is used with a spanning tree, the spanning tree takes precedence.

4. Interface settings page

4.1. Interface settings

Loop detection
Specify whether to enable or disable the loop detection function for the target interface.
However, even if set to enable, the loop detection function does not work in the following cases.
(1) The loop detection function for the entire system is disabled.
(2) The target interface is a port with mirroring settings(sniffer port).
(3) Used with spanning tree, and spanning tree status of the target interface is not "Forwarding".
Port Blocking
Enable or disable the Port Blocking function for the target interface.
If set to enable, the function blocks frames when a loop is detected.