Microsoft SQL Server 2000 supports several methods for connecting client computers to a server instance. The means for connecting the computers and the software involved depends heavily on the type of client, where the client is located, and the network infrastructure that is in place.
For SQL Server 2000, several common types of clients connect to the database server. Clients , in this case, are software applications that usually fall into one of these categories:
For these clients to connect to an instance of SQL Server 2000, they must use a client Net-Library that matches one of the server Net-Libraries that is listening for requests . The Net-Library is a dynamic-link library (DLL) that handles the communication between the client application and a network protocol. Each network protocol has a corresponding Inter-process Communication Component (IPC) API with which the Net-Library communicates.
Figure 9.1 illustrates the key components involved in the communication between the client and the server. The communication sequence from the client to the server is as follows :
Figure 9.1. IPC communication architecture.
This communication scheme is fairly straightforward, but it can be complicated by the fact that some network APIs can be used over many different network protocols. Each of the Net-Libraries and the protocols they support will be addressed in more detail in the "Network Protocol Support" section later in this chapter.