The arp detect-mode unicast command configures an interface to send ARP aging probe packets in unicast mode.
The undo arp detect-mode unicast command restores the default ARP aging probe mode on an interface.
By default, an interface broadcasts only the last ARP aging probe packet, and unicasts other ARP aging probe packets.
Ethernet interface view, GE interface view, XGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, MultiGE interface view, Eth-Trunk interface view, VLANIF interface view, VBDIF interface view, VE interface view, port group view
Usage Scenario
After the aging time of a dynamic ARP entry on an interface expires, the switch sends an aging probe packet (ARP Request packet) from the interface. If the switch receives an ARP Reply packet, it updates this dynamic ARP entry and the aging probe ends. If the switch does not receive an ARP Reply packet after the configured aging probe attempts, it deletes the dynamic ARP entry and the aging probe ends. The aging probe packet can be a unicast or broadcast packet.
If a non-Huawei device receives an ARP aging probe packet with the destination MAC address as the broadcast address from a switch, but the ARP entry of the switch already exists in its ARP table, the non-Huawei device discards the ARP aging probe packet. Failing to receive an ARP Reply to the ARP aging probe packet, the switch deletes the corresponding ARP entry. As a result, the traffic from the network side is interrupted. To resolve this problem, the switch must be configured to send ARP aging probe packets in unicast mode, and the non-Huawei device must be configured to respond to unicast ARP aging probe packets.
Precautions
If the IP address of the peer device remains the same but the MAC address changes frequently, configuring an interface to send ARP aging probe packets in broadcast mode is recommended.
If the MAC address of the peer device remains the same, the network bandwidth is insufficient, and the aging time of ARP entries is set to a small value, configuring an interface to send ARP aging probe packets in unicast mode is recommended.