Enabling MAC Address-Triggered ARP Entry Update
Context
MAC address-triggered ARP entry update enables the switch to update the corresponding ARP entry when the outbound interface in a MAC address entry changes.
Each network device uses an IP address to communicate with other devices. On an Ethernet network, a host, switching device, or routing device sends and receives Ethernet data frames based on MAC addresses. The ARP protocol maps IP addresses to MAC addresses. When two devices on different network segments communicate with each other, they need to map IP addresses to MAC addresses and outbound interfaces according to ARP entries.
- SwitchA functions as the master device and the server uses Port1 to send packets. SwitchA learns the ARP entry and MAC entry on Port1, and SwitchB learns the server MAC address on Port2.
- When the server detects that Port1 is faulty, the server uses Port2 to forward service packets. SwitchA learns the server MAC address on Port2. If the server does not send an ARP Request packet to SwitchA, SwitchA still learns the ARP entry on Port1. In this case, packets sent from SwitchA to the server are forwarded through Port1 until the ARP entry is aged out.
Procedure
- Run:
system-viewThe system view is displayed.
- Run:
mac-address update arpThe MAC address-triggered ARP entry update function is enabled.
By default, the MAC address-triggered ARP entry update function is disabled.
- This command takes effect only for dynamic ARP entries. Static ARP entries are not updated when the corresponding MAC address entries change.
- The MAC address-triggered ARP entry update function does not take effect after ARP entry fixing is enabled using the arp anti-attack entry-check enable command.
- After the MAC address-triggered ARP entry update function is enabled, the switch updates an ARP entry only when the outbound interface in the corresponding MAC address entry changes.
