Broadcast and Unknown Address Server

The final step in joining an emulated LAN is to make a connection to the BUS. The ATM address of the BUS is obtained by sending a LAN Emulation ARP request to the LES for the broadcast address. Once established, this connection is used to send broadcast messages to the BUS, which will add the client to a point-to-multipoint call including all hosts on the emulated LAN. Thus when a broadcast message (such as an IP ARP request) is received by the LAN Emulation host from its upper layers, it sends that message to the BUS, which forwards it to all hosts in the emulated LAN. Just as in the case of ethernet, the correct host responds to the sender, and thus the IP address is resolved to a MAC address.