Background

Background

Name registration is the process of associating a user-friendly name with a protocol-specific address. Host names and their IP addresses are a good example. Most people find it cumbersome to remember a workstation's address, such as “157.54.185.186.” They would rather name their machines something easier to remember, such as “MP3Server.” In the case of IP, DNS maps IP addresses to names. Other protocols offer ways of registering their specific addresses to friendlier names. Name spaces will be discussed in more detail in the next section.

Not only do you want to be able to register and resolve host names, you would also like the ability to map your Winsock server's address so that clients can retrieve it to connect to the server. For example, you might have a server running on machine 157.64.185.186 off port 5000. If the server runs on only that machine, you can always hardcode the server address in the client application.

But what if you wanted a more dynamic server—one that can run on multiple machines, perhaps a distributed application with fault tolerance? If one server crashed or was too busy, another instance could be started somewhere else to service clients. In this case, finding out where the servers are possibly running can create headaches. Ideally, you want the ability to register your server—named “Fault-Tolerant Distributed Server”—with multiple addresses. In addition, you want to be able to dynamically update the registered service and its addresses. This is what name registration and resolution is all about, and this chapter will address the facilities Winsock offers to accommodate distributed server registration and name resolution.