Due to the prominence of TCP/IP in the world of networking, most discussions of address resolution jump straight to the TCP/IP Address Resolution Protocol (ARP). This protocol is indeed important, and we will take a look at it in the next section. However, the basic problem of address resolution is not unique to any given implementation that deals with it, such as TCP/IP's ARP. To provide better understanding of resolving addresses between the data link layer and the network layer and to support for our examination of ARP, I think it's a good idea to start by looking at the matter in more general terms.

To that end, I provide here some background information on address resolution, exploring various concepts and issues related to the technique in general terms. I begin by discussing the need for address resolution in general terms. I then describe the two main methods for solving the address resolution problem: direct mapping and dynamic resolution. I also discuss some of the efficiency issues involved in practical dynamic address resolution, with a focus on the importance of caching.