The arp detect-times command sets the aging detection times of a dynamic Address Resolution Protocol (ARP) entry.
The undo arp detect-times command restores the default setting.
By default, the aging detection of the dynamic ARP entry is performed three times.
| Parameter | Description | Value |
|---|---|---|
| detect-times | Specifies the aging detection times of the ARP entry. | The value is an integer ranging from 0 to 10. The default value is 3. |
Usage Scenario
In case that the mapping relationship between the IP address and the MAC address of the peer device exists in the ARP entry of the local device, the local device will directly send data packets rather than ARP request packets to the peer device because the MAC address of the peer device exists in the ARP entry of the local device. The peer device fails to work or a network card is changed, but the device is not informed of the fault or change. In this case, the device will send data packets to its original destination MAC address, causing the traffic to be interrupted.
Therefore, to enhance the communication reliability, run the arp detect-times command to set the aging detection times of a dynamic ARP entry to update the dynamic ARP entry. Before a dynamic ARP entry is aged, the device will send ARP aging probe messages to the peer device. If the device does not receive an ARP Reply message after a specified number of attempts, the dynamic ARP entry will be deleted.
If detect-times is set to 0, the dynamic ARP entry is aged directly without detection.
Duration before deleting the aging dynamic ARP entry = Aging detection times x Interval for aging detection (Interval at which ARP probe messages are sent) Using the default value for detection attempts is recommended; if the value for detection attempts is set large, you have to wait for the response to the ARP aging detection for a long time if you configure many detection attempts, unable to promptly update the ARP entry.
Precautions
The command can be configured globally or on the specified interface. If the command is not configured on the interface, the aging detection times of a dynamic ARP entry will be the one configured globally. If the command is both configured globally and on the specified interface, the aging detection times of a dynamic ARP entry will be the one configured on the interface.
The interval between two detections is 5s and is not configurable.