Configuring Association Between ARP and Interface Status

Background

To minimize the impact of device faults on services and improve network availability, a network device must be able to quickly detect communication faults of devices that are not directly connected. Then, measures can be taken to quickly rectify the faults to ensure the normal running of services.

Association between ARP and interface status allows the local interface to send ARP probe packets to the peer interface and checks whether the peer interface can properly forward packets based on whether a reply packet is received. This triggers fast route convergence.

Pre-configuration Tasks

Procedure

1. Run system-view

   The system view is displayed.

2. Run interface interface-type interface-number

   The view of the interface on which ARP and interface status needs to be enabled is displayed.

3. Run ip address ip-address { mask | mask-length } [ sub ]

   The IP address of the interface is configured.

4. Run arp status-detect ip-address

   Association between ARP and interface status is enabled.

   

   The destination IP address of ARP probe messages must be on the same network segment as the IP address of the local interface. The probed device does not need to be configured.

5. (Optional) Run arp status-detect mode loose

   The interface is configured to send ARP probe messages in loose mode.

   • In strict mode, an interface sends ARP probe messages when the physical status is Up. The protocol status of the local interface remains unchanged only when the local interface receives an ARP reply packet from the peer interface and the source IP address of the ARP reply packet is the same as the destination IP address of the ARP probe packet. If no ARP reply packet is received from the peer interface within the allowable attempts, the protocol status of the local interface is set to Down.
   • In loose mode, an interface sends ARP probe messages only when both the physical status and protocol status are Up. The protocol status of the local interface remains unchanged only when the local interface receives an ARP packet from the peer interface and the source IP address of the ARP packet is the same as the destination IP address of the ARP probe packet. If no ARP packet is received from the peer interface within the allowable attempts, the protocol status of the local interface is set to Down.
   

   If association between ARP and interface status is configured on devices at both ends, you are advised to configure at lease the device at one side to work in strict mode. Do not configure devices at both ends to send ARP probe messages in loose mode.

6. (Optional) Run arp status-detect interval detect-interval

   The interval at which ARP probe messages are sent has been configured.

   Set the interval at which ARP probe messages are sent to a large value to prevent interface flapping upon operations such as primary/secondary switching.

7. (Optional) Run arp status-detect times detect-times

   The maximum number of times that an interface can consecutively send ARP probe messages has been configured.

   Set the maximum number of times an interface can consecutively send ARP probe messages to a large value to prevent interface flapping upon operations such as primary/secondary switching.

8. Run commit

   The configuration is committed.

Verifying the Configuration of Association Between ARP and Interface Status

Run the display interface [ interface-type [ interface-number ] ] command to check the status information and statistics of the interface.