In the usual networks, since every host has a unique IP address recognised among the stations in the network, why is a MAC address still necessary?
Suppose a station A wants to send to Station B. Station A knows Station B's IP address. But Station A would still send out an ARP to request for B's MAC address before sending. And then after having B's MAC address, A would then send the data with B's MAC address as destination address.
Why can't B just accept the packet just like how it respond to the ARP sent out by A? Then this way, station A wouldn't have to send out an ARP to ask for the MAC address and this would also remove the need for having a MAC address. Moreover, the IP addresses are unique among the network stations, why need another MAC address to recognise the stations?