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show loop-detect enhanced interface

Syntax

Description

Display status information about leaf device logical interfaces with loop detection enabled in a Layer 2 network.

You can configure loop detection on leaf devices for server-facing Layer 2 logical interfaces, and specify an action that the leaf device performs on the interface when it detects a loop, such as bringing the interface down. You can also configure an interval after which the device will automatically revert the interface to its state prior to the loop detection action following repair of the loop condition.

After you’ve enabled loop detection, the interfaces periodically send multicast loop-detection protocol data units (PDUs). If the interface receives a loop-detection PDU, which indicates a loop exists, the interface triggers the configured action to break the loop. The network administrator might then need to repair the conditions that caused the loop before reverting the interface to its state prior to loop detection. This command shows the configured loop detection parameters, current interface status, and detail about the remote interface that formed the loop.

Options

interface-name

Display loop detection status for the specified logical interface.

If you don't specify an interface name, this command displays loop detection status for all logical interfaces that have this feature enabled.

Required Privilege Level

view

Output Fields

Table 1: show loop-detect enhanced interface Output Fields
Field Name Field Description

Interface

Local interface name with loop detection configured.

Vlan-id

Local interface VLAN ID for which loop detection is configured.

ESI

Ethernet Segment ID (ESI) associated with the local interface.

Current status

Current status of the interface—Loop-detected or Normal [Link Up] (no loop detected)

This output section displays the following additional fields if the interface detected a loop. These fields describe the interface that routed loop detection PDUs back to the local interface:

  • Remote Host: Remote host name.

  • Remote Chassis: Remote host chassis ID.

  • Remote Interface: Remote interface name that is looping PDUs.

  • Remote ESI: ESI associated with the remote interface.

Note:

The interface causing the loop might be on the same local device or on a remote device.

Last loop-detect time

Timestamp when the device initially detected the loop and changed the interface status to Loop-detected.

When the interface has no Revert Interval set, or the Revert Interval timer is counting down the revert time after a loop has been cleared, if the feature detects a new loop, it updates the Last loop-detect time output field to display that most recent time loop detection time.

Receive statistics

Number of loop-detection PDUs received since the current loop detection period timestamp.

Action configured

The configured action that the device triggers upon loop detection.

Action count

Cumulative count of loop detection actions triggered on the local interface.

Transmit Interval

Default or configured interval at which the interface sends loop detection PDUs.

Revert Interval

Configured interval after the loop condition is repaired in which the interface state reverts to the previous state before the loop detection action occurred.

Sample Output

show loop-detect enhanced interface interface-name (no loop detected)

show loop-detect enhanced interface interface-name (loop detected)

show loop-detect enhanced interface (EX4300-48MP, all interfaces configured with loop detection)

show loop-detect enhanced interface (ACX7100-32C, ACX7100-48L, all interfaces configured with loop detection, no loop detected)

show loop-detect enhanced interface (ACX7100-32C, ACX7100-48L, all interfaces configured with loop detection, loop detected)

Release Information

Command introduced in Junos OS Release 20.4R1.