 When traversing the carrier's Ethernet network, the HVLAN frames can be forwarded using HVID only, MAC address only or a combination of both.There is an explicit bit in an HVLAN frame that prevents the carrier's core switches from learning the HVLAN frames' MAC address when unnecessary.To understand HVLAN operation, consider a scenario (see diagram) which illustrates the provision of 3 point-to-point services (blue, green, and red) over an HVLAN network.