Configuring Unicast ARP Probe
To check whether a peer device is reachable and to enable a device to learn a peer device's MAC address, configure a local interface to send a unicast ARP request that carries the peer device's IP and MAC addresses as the destination addresses.
Background Information
- Before an ARP entry ages out, the local device broadcasts an ARP request packet in an attempt to update the ARP entry based on the reply from a peer device. If the peer device does not support broadcast packets, it does not respond to the broadcast ARP request packet, so the local device considers the peer device offline and deletes the ARP entry. As a result, services will be interrupted between the two devices.
- If the local device is new, it will broadcast an ARP request packet to learn the MAC addresses of other devices. If a peer device does not support broadcast packets, it will discard the ARP request packet, so the local device will not learn the peer device's MAC address. As a result, new services will not be started between the two devices.
Pre-configuration Tasks
Connect interfaces and set physical parameters for the interfaces to ensure that the physical interface status is Up.
Configure link layer protocol parameters on interfaces to ensure that the link layer protocol is Up.
Data Preparation
No. |
Data |
---|---|
1 | Destination IP address for the unicast ARP request packet to be sent |
2 | Destination MAC address for the unicast ARP request packet to be sent |
3 | Type and number of the interface for sending out the unicast ARP request packet |
4 | Inner tag value for the unicast ARP request packet to be sent |
5 | Outer tag value for the unicast ARP request packet to be sent |