Client/server communication (the interfaces file)

Adaptive Server communicates with other Adaptive Servers, Open Server applications (such as Backup Server), and client software on your network. Clients can talk to one or more servers, and servers can communicate with other servers by remote procedure calls.

For Sybase products to interact with one another, each product needs to know where the others reside on the network. Names and addresses of every known server are listed in a directory services file. This information can be stored in a directory services file two different ways:

After your Adaptive Server or client software is installed, it can connect with any server on the network that is listed in the interfaces file

When you are using a client program, and you want to connect with a particular server, the client program looks up the server name in the interfaces file and connects to that server, as shown in Figure 1-1. You can supply the name of the server by using the DSQUERY environment variable.

On TCP/IP networks, the port number gives clients a way to identify the Adaptive Server to which they want to connect. It also tells Adaptive Server where to listen for incoming connection attempts from clients. Adaptive Server uses a single port for these two services (referred to as query service and listener service).

On SPX networks, the socket number gives clients and servers a way to identify each other.

Figure 1-1: Communicating with a server using the sql.ini file

During installation, Studio Installer adds entries to the sql.ini file for the new Adaptive Server, Backup Server, Monitor Server, Historical Server, or XP Server.

NoteYou can use Windows NT Directory Replication to replicate sql.ini in the multiple locations. See the Microsoft documentation for information. You can also use NT Registry to keep the interfaces file information.