The mappings of the MAC address to the IP next hop in the forwarding table illustrated in Figure 2 are advertised by a control protocol, thus eliminating the need for flooding of unknown unicast traffic across the overlay. The control protocol is extensible and includes useful MAC-address-specific information such as VLAN, site ID, and associated IP address (for IP hosts). This rich information, most of which is not available when you rely on data flood learning, is instrumental in building into OTV the necessary intelligence to implement multihoming, load balance, prevent loops, localize First Hop Resiliency Protocol (FHRP) capability, and even localize Address Resolution Protocol (ARP) traffic without creating additional operational overhead for each function.