Who Is It, Honey?

Who Is It, Honey?

If someone drives up your street and stops in the driveway, you're probably curious about whom it is. Likewise, when someone sends you data over a LAN, you might want to know who sent the data.

With Ethernet, the Ethernet header includes a source address field in addition to the destination address field. The source address identifies the Ethernet address of the NIC that sent the frame. Figure 5-6 shows an example, listing the addresses for all three PC's NICs, as well as the basic logic used.