 The DECnet software assigns the last three bytes of the MAC address to be where reflects the DECnet network address "xx.yy" of the host.This eliminates the need for DECnet to have an address resolution protocol since the MAC address for any DECnet host can be determined from its DECnet address.When the least significant bit of an address's first octet is 0 (zero), the frame is meant to reach only one receiving NIC.