What are the methods of assigning IP addresses to a workstation?

Method 1: Manually assign an IP address. You can manually assign an IP address, network mask, and even DNS servers to a particular network interface. This is useful if you need the IP address to always be the same, or if you have no DHCP server. (See #2). It has the disadvantages of requiring the network administrator to keep track of the manual IP address in order to prevent conflicts, and also requires manually changing it when necessary.

Method 2: DHCP. This is the most common way of assigning IP addresses. A DHCP server (DHCP = Dynamic Host Configuration Protocol) receives a request from a workstation, consults an internal list of available and assigned IP addresses, and then responds with an IP address and other information such as DNS servers and default gateways. This has the advantage of being very easy to use, and requires a lot less work on the part of the network administrator. However, if the server or service is unavailable for some reason, computers may not have the ability to set up their addresses except for APIPA. (See #3).

Method 3: APIPA (Automatic Private IP Addressing, a.k.a. Zero Configuration Network). This isn't really a method per se. If your computer is unable to contact a DHCP server and has not been manually configured, it may set up an APIPA address. It assigns itself a random address in the range of 169.254.0.0/16. (169.254.0.1 - 169.254.255.254).