VLAN MAC address reconfiguration

Switches use one unique MAC address for all VLAN interfaces. If you assign an IP address to a VLAN interface, ARP resolves the IP address to the MAC address of the routing switch for all incoming packets.

The Layer 3 VLAN MAC Configuration feature lets you reconfigure the MAC address used for VLAN interfaces, using the CLI. Packets addressed to the reconfigured Layer 3 MAC address, such as ARP and IP data packets, are received and processed by the routing switch.

Packets transmitted from the routing switch (packets originating from the router and forwarded packets) use the original Switch MAC address as the source MAC address in Ethernet headers.

ARP reply packets use the reconfigured MAC address in both the:
  • ARP Sender MAC address field

  • Source MAC address field in the Ethernet frame header

When reconfiguring the MAC address, you may specify a keepalive timeout to transmit heartbeat packets that advertise the new MAC address

By configuring the MAC address of the previously installed router as the MAC address of each VLAN interface on the Switch, you can swap the physical port of a router to the Switch after the switch has been properly configured in the network.