IP Routing Protocols

ADDRESS RESOLUTION

As explained in Appendix B, each device attached to a single physical LAN is identified by a specific MAC address. We also learned that other addresses are assigned, such as network addresses. The vast majority of MAC addresses are assigned by the manufacturer before the product is shipped to the customer or when the product is installed at the customer's site.

We find ourselves with an interesting problem which we began to address in previous discussions: how to relate the MAC address to a network address and vice-versa. As an example on a LAN (and see Figure C-1), if host A wishes to send a datagram to host D, it may not know the MAC of host D. To compound the problem, the higher layer network address may also be unknown ...